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January 2025 Blog

Radio Frequencies RF That Hi-Fi Can Pick Up.
We've mentioned before about RF & Ferrites to help reduce RF interference. See our Turntable, Phono & Cables page which was writen 2013 vut is as relevant with the growing amount of Mobile Devices & Broadband that is taking over The Airwaves as Analog TV ended to free up these Broadcast Frequencies. The page tells that Transistors can amplify way beyond 20kHz hearing limit, a 2N3055 first around in the late 1960s can go up to 2.5MHz and a small signal transistor BC550 can deal with 150-300MHz. This will have it's uses but in Hifi it's far too Wide Range. Looking at Amplifier specs 20Hz to 20kHz is often quoted, some go up to 30kHz but others go up to 100kHz. Looking online, UK allows Frequencies to be used, http://static.ofcom.org.uk/ shows a lot of Broadcast Frequencies. Ones starting from 19.95kHz is a bit of a worry, Maritime ones will be more Coastal if it seems Insane to allow anything under 100kHz, there is a lot of it. Time Signals are a Bleepy type noise like an old Dial Up Modem & long wires certainly can pick up Picture & Mouse 'noise'. There appears to be 'A Lot' that could potentially be picked up by Hifi which Vintage Amps can run into Trouble with as 50 years ago this wasn't a problem. Excessive RF can trash certain Wide Bandwidth Amplifiers, unwanted RF won't be heard but will Waste A Lot Of Power. Some early designs are just too Wide Bandwidth & need taming down, so they remain safe. One amp picked up RF so badly it Oscillated heavily, originally it used lesser grade capacitors. Modern Capacitors like the Panasonic FC range don't quote a Frequency Range if do give detail on a 100kHz test, which could be way higher than a typical UK-EU TV Grade Capacitor. Google finds Mobile Phones are out of the 100kHz & 300kHz range at 800MHz-2.6GHz. Broadband is over 20MHz if in 2013 we found 2.4GHz-5GHz. Computer LCD Monitor Noise can be a Problem, to see a Monitor can be as low as 30kHz as a Scanning Frequency, which isn't the 50Hz-60Hz refresh rate. We still get RF Noise on our Luxman LX33 1979 valves amp using a 2m cable on any LCD monitor. This therefore is what it picks up & with Lounge TVs being LCD monitors, there's the RF problem. To see as low as 15kHz & 30kHz-83kHz seems rather archaic like the old CRT TV with the Line Output Transformer Whistle. 1960s TV on 405 lines had an even worse whistle of 10kHz & getting our first TV in 1987 the 625 line whistle of 15.6kHz was quite noticeable at our age then. Computer & TV RF noise hasn't been sorted properly, mainly because Hifi of today is well tamed to not have it sounding, Amps past 1973 don't usually pick up RF noise. Ferrites do help, if these are none to limit the 50kHz-300kHz range noise. The Hifi Itself must have it's own RF Attenuation. How to sort the LX33 valve amp picking up RF from cable that goes near the LCD monitor maybe is only solved by moving the amplifier, if it's set up to be easily used. The Computer Mouse uses a much lower frequency of 125Hz to 8kHz on high spec Gaming Mice. We've found some Hifi can pick up Mouse Noise with an amp on the Desk, to pick up Noise from the Twisty Glass ESL Lightbulbs also possible. Again most Hifi is tamed to not pick up these Noises. Limiting Hifi To Stop RF Noise. The trouble with this is like High Filter (Low Pass Filter) on older amps like Quad. It restricts the Treble Detail. Some earlier amps had the Phono & Preamp with a RF Limiter that used to pick up Car Ignition noise. Some Amps go Too Far in design, making the 10kHz Square Wave so restricted it looks like a Saw Tooth or Dog Tooth shape, not the Square Wave shape some amps can do up to 100kHz, such as our LX33 that picks up RF. Can't have it all.

The "Rock Sound" In Amplifiers.
You Need To Know What An Electric Guitar Sounds like through a Marshall or similar Amp. One we heard put out such heavy Sub Bass all the Ornaments Fell off the Shelf! A good way to get rid of those Cheesy Trinkets beloved by many. Rock Guitar has a Solid Midrange Power. Lemmy on his Guitar Amps used to put Midrange to Full to accentuate the Rock Sound as early as 1966 on the Rockin' Vickers CBS B side 'I Don't Need Your Kind'. Your Hearing can make you like Amps with a more Recessed Midrange, 'Further Back' soundstage which leaves Voices both Male & Female, sounding a bit Thin. You only really notice that by Playing Other Amps. The Ultimate Rock Sounding Amp is the 1970 Trio-Kenwood KR-6170 Jumbo, it;s a Guitar amp & was designed to Suit Rock Guitar, if as original they much tamed it. We've had that on Speakers a few days since changing the Tone to sound much better than the Thick Lumpy Sound. Thinking there really can't be anything 'Better' as the Sound is so Listenable, to try the other Receivers. These have all had a lot of Speaker Time so they are well understood. But after the KR-6170 to feel the Sound wasn't as Far Forward as the KR-6170. They were all Great Sounding, if wanting the more Solid Rock Amp Sound the KR-6170 now has. Others sounded Sweeter as the Midrange a little further back, the Wide Stereo in some Amps more than Others. The 1965 Sansui TR-707A was considered the nicest sound if still the more 'Relaxing' Midrange Tone. Back to the KR-6170, it's like the TR-707 with The Midrange Control turned up, if it doesn't have one. The Trio-Kenwood KR-6200 still here so try that. It has a Midrange Control & we've said before it 'Needs -3 on Midrange' to not be so upfront. What you're used to elsewhere certainly does Vary. Try 70s Rock that the KR-6170 did so well, the KR-6200 on -3 Midrange sounded too thin, remembering the KR-6170 sound on the tracks last time, on Headphones. Set the Midrange Flat & the Guitar Solid Roar sounds more like the KR-6170. Black Sabbath 'Paranoid' has the Guitar Power, but -3 midrange loses it, to sound More Domestic. Try The KR-6170 on Headphones, after using the KR-6200. It is a Different Sound, more Authentic on the Rock Guitar Sound, the KR-6200 is not as Subtle. The KR-6170 has precise Impedance Maching & Unique Circuit Design on the Preamp to sound the way it is, the Power Amp board is much like the KR-5150 that is 33w also, just a few resistor changes. Swapping KR-6170 to KR-6200 with matching Midrange -1 on KR-6200 & playing Flat on KR-6170, to get Midrange to sound similar if the KR-6170 has what very few Amps have, a Rich Solid Bass that sets the KR-6170 apart on Black Sabbath & Jimi Hendrix. KR-6170 (our version) has a very solid Funky Bassline. The KR-6200 stays For Sale, certainly is a good one but Domestic Amps don't have the Bass Weight For Rock Guitar. After 3 years the KR-6170 is Finally a Keeper, nothing sounds quite like it, yet nobody wanted it. Because it Has No Cred & takes a lot to bring out this Sound. Rock Guitar as we said needs Knowing A Guitar Amp Loud in a Domestic Room to know what Guitar Can Do. The Guitar Input on the KR-6170 we've not tried, it's the Influence for the KR-6170 Sound. If Hifi Makers put This Sound in all amps, there'd be Trouble as it Sounds so Great, but They're Not Getting That Sound. Guitar in Bigger Stacks played Live At Gigs usually goes through a Mixer, not Plug In Direct into the Guitar Amp. These Days, the Live Rock Guitar Sound probably is all via ICs. No One Instrument in Music is as Awesome as The Rock Guitar with the Right Pedals, The Right Amp & a Fine Axeman on the thing.

First 'Comet' Advert Januay 1969 Hi-Fi News.
As we've Blogged before, the arrival of Aggressive Hifi Discounters upset the Hifi World A Lot. It made Brands who were previously known for quality to Unwisely get in with the Discounters. By making Hifi seem 'Too Cheap' the reality became the Discounters Price became the previous RRP Recommended Retail Price. The Much Advertised Quad 33/303 pre & power pair is £98 in every shop, but Comet start offering the pair at about £83 which is a 15% Discount. In Reality this will remove most of the Profit in New Gear plus the Shop has the Usual Overheads & VAT. Pile It High & Sell It Cheap in what are More Expensive items really isn't good for a Market. To sell Fruit & Veg under this idea similarly only drives down the Price to Buy In & The Quality of the Goods. To see Naive Types on Record Sites complaining of a £150 item needing £8 Special Delivery Post is how Thoughless Buyers are, today they really believe Post Is Free yet it's clear it's Built In to the Price, if you buy Multiple 'Free Post' items the Seller gets paid post twice. Some now offer a Discount on Buying Two as they know Buyers question it if most don't. Comet over the Years gets All The Brands except Yamaha. Quad, Leak, Goodmans, Rogers, Arena, Truvox, Teleton, Garrard, Wharfedale, Thorens, Akai & Sharp all all Big Brands in their First Advert. Marantz, Pioneer & others are added over the years. 10% to 15% Discount is typical if in later years, beyond 'End Of Line' clearouts especially on the unselling 'Monster Receivers when they got much bigger Discounts, 20%-25% and more. It All Adds a Cheapness & Desperation to Hifi. The Market Will Only Pay A Price, but look at Washing Machines prices, today £800 will buy you a good model one as it did 20 years ago. The Quality will have Nose-Dived & how long these items last is the Worry, look at the TV E-Waste piles of gear that is probably not Ten Years Old. Comet only has One Shop in Jan 1969 in Clough Road, Hull. The Prices being 15% less may seem a bit Dodgy, but they put a line "Comet Guarantees That All Prices Quoted Are Genuine" which is reassuring plus they add "All Items Offered Are Available At Time Of Order" which HFN letter writers often complained wasn't the case in other shops. The HFN advert deadlines for Classified Small Ads is a month ahead, for the Bigger Ads isn't so clear if the idea Three Months in later issues will get some items out of stock or no longer available. Seems Comet will have good stocks of the items which again Leads The Way on other Advertisers for a Third Time. Great Business Model, Initially Great for the Buyer to Get 15% off, but ultimately the Harsh Discounts just make Manufacturers Cut Costs so that a previous £300 model once given the Expected 15% Discount really is only made to a £255 price level on the Next Year's Model as the Market Wants It Cheaper. Hifi Quality is noticeably Lower by 1974, then lower by 1977 & by 1979-80 it's really a long way from the 1969-71 models. You Gets What You Pays For.

Harman-Kardon Receivers & Amplifiers.
This isa USA Brand built in Japan. The Early ones are Rarely seen in UK, most online are 110v versions. We first got a HK-730 around 1992 for £20 at a Car Boot & thought it was better than other amps, in the league of Marantz. But as so early for us to not properly appreciate it, but you have to start somewhere. The only HK we found was the HK-930 from 1972. In the Rare wood case, it had the Dual Power Supply but didn't think it was as good as the 1976 HK-730. But to see a bargain buy on a 110v HK-560 40w receiver, to snap it up & find how great it sounds, so unlike a typical thin grainy 1979 amp. So to wonder what came before & after in this Obscure Brand. To find 220v or 240v ones is tough. The 110v ones have the skinny mains cable, the 220v-240v will have a thicker wire. They aren't multivoltage if it could be possible to swap a 230v Transformer if you have a spare one. Our Lists of Receivers & Amplifiers pages shows HK only arrived in UK in 1973... receivers 630EX 30w £149, 930EX 45w £209. 1974 Citation 12 60w power amp £185. 1975 amp Citation 15 ??w £307. 1976 receivers 330A & 330B 22.5w & 20w £110 & £115 +VAT, Model 50+ & Model 70+ quadro hangovers £139 & £219 no power ratings. 1977 A401 20w £105, Citation 16 150w power amp £465, Citation 11 preamp £228, Citation 12 De Luxe 60w power amp £209. Receivers 730 40w £249, 430 25w £179, 330B 20w £125. 1980 amps 503 40w £221, 505 60w £301, Citation range: 16A power amp 150w £665, 17 preamp £488, 19 power amp 100w £514 options no LED or Graphic EQ on pre. Receivers 560 40w £310, 670 60w £443, Citation 80w £1154. 1981 HK725 preamp £117, HK770 power amp ??w £222. Harman-Kardon best known for the Citation pre-power range & the 20w HK 330 receiver we've seen a few times. Earlier Models. The HFE site shows some 1960s ones that are probably 110v only. Models 200, 210, 230, 520, 530, 720. 1956 valve receiver D200 very early. FA3000X looks pre 1971. What Came After? with No Hifi Year Book, to dig around on the HFE site to find the 1980s ones that show a level of quality, before the brand descends into the 'Black Ranges' that seem more Mass Market. 1983 HK 330i 20w. HK380i 30w. HK-570i 45w. HK-580i 45w some of these will be 1984-85 models. 1986 HK795i is 70w. These 'i' ones early-mid 1980s with 4-Digit HK being 1990s to 2000s. Look At The 1983 HK-570i. This being the Next One to the HK-560. HFE shows Six Update Bulletins for this model. Still All Transistors on Phono, Pre & Power Amp which is unusual by 1983. It's not so different to the HK560. Look at the 1986 HK-795i is heading deep into CD & IC territory on all amps, how about HK? Still Transistors & No Relay, starts to head into a Different Territory in design with the Class B 'IC' type circuitry that Yamaha did in 1977. Probably still is way ahead of other 1986 Hifi, but Does It Have that Sound still when The Competition was often Bright, Harsh & Grainy?

1966 'Vox' Organ On 'The Repair Shop'.
Seeing a re-run of this S8 E11 episode, to see they briefly show the 'Vox' name on the back, easy to miss. Later shows as "Vox Continental II" which ebay show in the £2000-£3000 range. They suggest it's a 1966 one used on The Monkees 'I'm a Believer' so a True 1960s sound together with the 'Farfisa' organ used on ? & The Mysterians '96 Tears' from the same year. Oddly UK Record Collectors call any Organ a 'Hammond' which is probably wrong, the Hammond was more a Supper Club-Cabaret sound & the bigger Wurlitzer Theatre Organ sound & many mindless Easy Listening LPs of the late 1960s into the early 70s were often found in our LP Dealing days, they did still sell for 50p in the late 1980s so to buy them. The Organ is a very complex unit, the nearest we've come to one like it is the 'Beat Box' Rhythm Generator in the 1970 Trio-Kenwood KR-6170 Jumbo. Luckily it all works so didn't recap the Guitrar, Echo-Reverb or Sound Generator parts. The Organ uses one Board per note & stuffed with Germanium transistors like the KR-6170 uses, the old Allen Bradley resistors, lots of Film Capacitors & a few Electrolytics which seemed to be the failing here, 1966 Capacitors often long replaced in Amps of the 1965-67 era. They don't show too much & they have to get another to really get the Organ working, if not saying much, if we can imagine it'll have needed a lot to service, as the KR-6170 did. They should tell more on how Difficult Audio Gear is to get right, the idea it's a Cheap Repair comes from TV Grade repaitrs that "Just Got It Going" rather than the way we do it to get it use-daily. There is little point otherwise, if The Cost puts many off, even with the Best Gear. The Owners got it from their Dad, they show a c.1970 picture of him but don't give a name ot group. The Organ will have been Expensive to suggest at least a Semi-Pro name. The Sound from it was interesting, hearing it 'Live' not mixed down. Very Strong very 1966 sound, nice item to have if you play it. Like the KR-6170 Sound Generator as used in Organs of the 1970-75 era, a time where Organs Sold as the 'Henry's Rafio' 1968-72 Catalog shows. They are pre IC with a limited range & the Spring Reverb is a limited use, but Oh So Retro, to Imagine more open-minded thinking Musos would like the Sounds, if sadly Music ain't what it used to be compared to the Last Gasp in the Britpop era in 1992. Kids have No Bands to follow so to Hope that Music Revives one day, else you'll not need Hifi much.

Revealing How Poor TV Sound Is By Having A Reference.
With Trying Ideas on Amplifiers to get a Better sound, it often takes a few tries to perfect it. To 'Reset' the Hearing after one amp needs a few fdays on a Known Amp & to Hear a Reference can Reset it even faster. This shows how Suggestible Your Hearing Is, Compensating for What The Sound Lacks, which means all of it, Bass, Midrange & Treble. One Amp lacked Midrange & what Your Hearing does is to Compensate to make Midrange 'fit' better. This can be from Using the Amp the Day before & It Stays until you Play Hifi again. Crazy but True & it can mean we avoid listening to some amps not wanting to Upset the Hearing Balance. This Hearing Effect can make some think Awesome Hifi is Not Good as they only know Poorer Hifi with an Unnatural Balance. A Neutral Amp that Sounds Spot On can sound 'wrong' if your Hearing has Compensated for the Non-Neutral Amp. We've gone on about this for Years, but you'll not read a thing online about it. You can be made to like Non-Neutral Amplifiers by the Lack of a Reference Amp. This will Confuse Many, if we can hear when an Amp is less Honest with Artficial Sounding Treble, Recessed Midrange & that Boomy Retro Bass. A Reference Sound is A Live Instrument. It can be a Voice in the Room, if this can be tricky as People's Voices can be Deep & Resonant to Thin & Wispy. Some Voices have a Squeaky High Pitched Sound, as in American Women on the Zoo TV Shows. Some have the Squeaky Voice that also has a Deeper Bassy sound to it. A Voice is not such a good reference. What Is Then? To Have an Instrument like an Electric Guitar, or in the case of the 1970 Trio-Kenwood KR-6170, it has a 'Rhythm Generator' like a Beat Box of limited range unlike a later Synthesizer. The 'RG' creates Beats & Boops like you find on Organs of the Era. To Speed It Up or Slow It Down, adding Reverb gives a very clean & solid sound, because it's a Live Instrument & the KR-6170 is a PA amp if only 33w, on 95dB speakers the 'RG' is very strong & loud with a precision. Going Back to TV Sound, to hear how Weak It Sounds lacking the 'Live' Precision. Rarely do you Hear 'Live' sounds without any Mixing Board limiting, the Blog Above with the 'Vox Organ' was a rare chance to hear 'Direct Live' music. Hearing the Vox on the KR-6170 & it's own 'RG' shows what a Great Voice the KR-6170 has, after much upgrading, removing limiters yet keeping the Circuits as Their Design as they showed something special even 3 years ago, if taking years to perfect. Thankfully no-one bought it. The Sound we put in the KR-6170 are ideas from many amps. We thought in a Blog Above if the KR-6170 could be made into a 75w Amp with the JVC 5040 transformer, if possibly it could, to leave it as-is fo reasons of what trouble you could end up with. Especially after trying more with the 1969 Trio KA-6000, things don't always work out. Good to think of ideas, but generally if an amp lacks, sell it & go find another. To TV Sound. What you were used to, eg 'Pawn Stars' soundtrack uses Rock Guitar a lot. It's recorded as Live as a guy playing the short segments & however the Sound Production mixes it. They can't limit it too much as it's not Mixed with other sounds, it's a Guitar Riff added on. With other Music & Voices to hear they aren't so good sounding after the Rock Guitar & the KR-6170 'RG', they sound Soft, Lack Dynamics but it's a TV Show. Similarly on 'Wheeler Dealers' the Music can be much Louder than the Voices giving another TV show that is rather varied in Sound Quality, some can be Soft & other Music can be Much More Kicking & Louder. To Assume they Mix TV Sound on Small Low Powered Speakers not to Realise.On 1960s Vinyl Records, some tracks have No Mixing Down so the Voices are very 'Live' & personal sounding. The Beatles 'Revolution' uses Hard Psych Guitar mixed very 'Live' without going into clipping, the Guitar plugged into the Console rather than a Guitar Amp that was with a Microphone. The 'Hard Rock Guitar' sound is usually mixed down to not be Too Heavy.

Pre Amp Out & Power Amp In Sockets On Receivers & Amplifiers.
The First Amplifier to have these Preamp Out & Power Amp In Sockets was the 1965 Sony TA-1120 early one. They called them "Pre Amp/Amplifier Junction Check Points" which will have just confused owners & pity those losing the Short Connecting Cables. Sony used these on Amplifiers if not Receivers in the 1960s. The Use we see the "Pre Amp Out" is to put the Preamp into a Higher Power Amplifier or as we've heard many times, to use half the amp if the other half is faulty in some way. The 1971 Sony TA-1130 has these sockets if labels more clearly as "Pre Amp/Power Amp" and "Pre Amp Output" & "Power Amp Input". The 1970 Trio-Kenwood KR-6170 has these too adding a switch to add the Reverb output too. Their 1969 TK-140X has these if the 1967 TK-140E doesn't. Some amps & receivers have these or don't if the 1972 Trio-Kenwood KR-6200 only has 'Pre Amp Out' on wanting to try the KR-6170 pre through the KR-6200 power if not possible. To be able to try the KR-6170 through the 1969 Pioneer SX-2500 was possible but it beings up incompatibilities. The Levels Are Not Standardised. Trying the KR-6170 before into the 1971 Sony TA-3200F power amp the levels were too far apart. The 1971 Sony TA-1140 preamp could be played through the TA-3200F. In later years, possibly by 1973 from trying Yamahas a while back, the Standard "!v Level" on both Pre Amp & Power Amp makes this possible. But the Earlier Amps & Receivers can be 400mV, about 750mV, 1v & also 1.4v. The 1971 Sony TA-3200F power amp has a level switch to select 0.3v or 1v which adds another giving 0.3v (300mV) to 1.4v as on the Valved Quad II level. Finding this out in 2002 having the Quad set here & the levels from a few preamps didn't suit the Quad II, only it's own Quad 22 preamp. Having the McIntosh preamps & power amp to find similar with the Tube Technology preamp being too loud for the McIntosh & bringing up the Noise Floor too much as the levels didn't match. Those in later years, by the 1980s, buyimng a Preamp & getting a Power Amp from a different brand will be better matched in Volume, but the Dark Art of Impedance will have some Different Brand Pre-Powers sounding too Dull or Overbright. There really is little point not using a matching Preamp & Power Amp. We tried the Sony TA-2000F on the Tube Technology 100w Genesis & found they were Dull Sounding together if the TA-3200F being the Correct Match sounded very different. Only Worth Mixing Preamp & Power Amp within The Same Brand & Age, if again there will be design changes over the years. Interesting to see if one Yamaha Receiver is better with the Amplifier's Power Amp or it's own one. The Answer there was still the Full Amp as Preamp & Power Amp were always the Best Sounding. The only one that was Better was our Redesigned TA-1140 on the TA-3200F power amp. Currently got a TA-1130 & the Sony TA-2000F/3200F pair so we could mix them about to compare. Another Thing is if you try a 25w Amplifier as a Preamp on a 100w Power Amp, it'll still have the more limited 25w sound. Found this in 2012 with the 1978 Leak 3200 on the 'Solds Gallery', probably using it on a Yamaha. A 25w Power Amp is best with a 25w designed Preamp. A Very Decent Preamp on a lower power Amplifier can sound much better on a Higher Powered Amp, but that's only using Upgraded Amps, the Shop-Bought spec amps are Sold to be Universal & Safe. The 1970 Trio-Kenwood KR-6170 preamp sounds great on the 1969 Pioneer SX-2500 power amp, if the volume difference needed volume near '6', not the usual '3', but interesting to hear. Use Blanking Plugs. These are the RCA Phono type items that are found on Amps sometimes, it 'Blanks' an input, so to use on the 'Unused' part of trying a Preamp on another Power Amp, to keep things safe, especially the Unused Power Amp. Only connect any amps when switched off & hand near the Speaker Switch or Power Button as from what the above says, you might get a Really Loud Pre on a Really Loud Power Amp.

Different Types Of Fuses On Mains, DC & Audio Stages.
On Amplifiers you sometimes find a Different Type of Fuse, seen by us on some 1969-73 era Hifi. These have a 'Spring' section inside & generally are Rarely Seen & Used on the AC Mains Fuse stage, pre the Transformer. These are called "Slow Blow" or "Anti Surge". A Nov 1969 HFN article mentions these as being 50 years ago the info isn't generally known. They say there are Fuses with One or Two 'springs' inside, we've only seen the One 'spring' version. Some amps have Fuses in Clips so to see the Fuse Wire Bend on Turn-On is exactly what the Anti-Surge spring does, it keeps the Fuse Wire straight. A Blown Fuse shows the Wire Bent as it heats up & Fails over it's Rated Current. The 'spring' acts to steady the Wire not to Break. A 2A fuse will always be a 2A fuse if in 'Quick Blow' standard single wire Fuse or the 'Anti-Surge' type with the 'Spring'. Looking on ebay there are Plain One-Wire Fuses called 'anti Surge' but they aren't. There are ones with a 'Blob' on the Fuse wire inside the Glass, these are likely the Modern Version of a 'Slow Blow' having a section, the 'Blob' to take a Surge yet not be a Fast Blow. Ebayers clearly don't know what they have, so look on 'RS' Radio Spares site. These show no 'Anti Surge' ones if Glass or Ceramic ones. On the 'Farnell' site they only have One Anti-Surge 'Time Delay' in a 16A 32mm fuse. Unless it actually is labelled correctly there are No Anti Surge Fuses despite ebayer's incorrect claims. In Reality in Hifi, there is No Real Need for a Fuse beyond the Basic 'Quick Blow' Fuses which still do take time to Blow, based on seeing Damaged Amps still with good Fuses & correctly rated ones. A 3A Fuse covers a 750w Amp, as in the VA Rating, not the Power Amp rating. A 1977 Yamaha CR-2020 rated at 690w (690VA) is close to the 3A rating so a 5A may be better. Some Amps & Even our last Panasonic 32" CRT TV did a 'Boing' on turn on. It's part of the design in some early amps, our 1966 Akai AA-7000 always does this Noise which is Reassuring rather than a worrying noise, once your used to it. The TV Thump is more likely the Turn-On Surge creates some sort of Uneven AC Balance due to the 3kV CRT voltage & a more Heavy Case would deaden it. In Upgrading Amps, to see the Original Fuse is much too low can get Values Uprated, but that's for A Tech to Decide. If You Need a 3A Fuse, Do Not Fit A 13A one, or awful unsafe ideas like Wrap Tin Foil over a Blown Fuse or put a Nail In, like we found on a Leak Stereo 70. If the item blows a Fuse, it does it for a Reason. A Recent Fisher 1968 Receiver had the owner put metal bars instead of Fuses which Much Overheated as it couldn't blow a fuse from Failed Parts. This is called "A Fire Risk". A Fuse is there to Protect You. The General Idea on a Fuse Blow is to put another one in, yet The Surprise people find it Blows Again, wondering why. If a 3A fuse blows, don't put a 13A one in as it may hold it working, but can also be Dangerous!

The Power Rating Game In Power Amplifiers: Can You Upgrade Power?
To see on the 1979 Harman-Kardon HK560 at 40w & HK670 at 60w on comparing on the 560 review...."Not much 40w to 60w in reality. HK560 on ±38v & HK670 on ±43v." So just ±5v makes the difference 40w to 60w? Look at other Amplifiers to see this is a standard thing with what looks an Impressive Power Increase for only a small Voltage Gain. In Reality it's 10v more as 76v to 86v as in the Pre Differential amplifiers with a Single Voltage Rail. Here the 1967 JVC 5040 rated 75w runs on 92v HT, the 1969 Pioneer SX-2500 at 72w is also 92v HT, the 1970 Trio-Kenwood KR-6170 Jumbo is rated 33w on 70v HT. The 1969 Trio-Kenwood KA-2000 at 13w runs on 35v HT. To compare Power Amp Circuits can show small differences, but generally they aren't hugely different in the Capacitor Coupled era beyond the Transformer Coupled designs. The Differential era gets more varied designs that don't really compare to the CC era ones. You Want More Power In Your Amplifier? Upgrading certainly betters the Sound, but overall you'll still have the Same HT voltage whatever you do. Current Handing will improve & to Use the 'Power Into 8 ohms' test using a Resistor as a Speaker & the Oscilloscope on the mode to test Power. We've never bothered test that as it'd gice misleading Power Ratings, much like the "Power Ratings" page has with 50w being 25v to 33v Sine Output, a 32v Sine output is rated 72w on one amp ^ 50w on another. To Get More Power needs a Higher HT Voltage. Ome amp we have rated 25w, but on finding an 'error' or deliberate limiter to keep it 25w, it could be made a 45w amp with a good gain in HT by doing certain things right & making the Amp 'fit' the Higher HT, as you can theoretically do with putting in a Higher Voltage Transformer. Looking at the 1967 JVC 5040 Transformer & Power Amp board that were known working, but the Amp was bought as a Spares Amp with no case as the Input Selector was damaged. Here we have a 75w amp. The KR-6170 on 70v HT is 33w, the JVC 5040 is 75w on 92v. The Trio-Kenwood KA-6000 is 48w on 86v which is quite a difference for 6v HT & why we put Doubled Outputs in the Spare Holes on the Heatsink to make it about 65w-70w. Here the Current adds to the Wattage, if in Reality a Doubled Outputs 65w 1970 Akai AA8500 is otherwise a 40w amp by it's voltages. It's How 200w-300w Amps Are Made, using multiple Output Transistors to Boost Current if not be much Louder than a 120w Regular Single Outputs Amp, as in One Pair of Output Transistors, not 2-4 Pairs. To See How Misleading A Power Rating Can Be. Some amps play Louder than ones of Higher Power, if the High Power Drives Speakers with More Confidence & why Doubled Outputs are Popular in Higher Power Amps. The Pioneer SX-1010 rated 110w puts out 39v Clean Sine around what an 80w Amp would do in terms of Voltage. A True 110w Amp like the Yamaha CR-2020 gives 43v Clean Sine. The JVC 5040 Transformer Could Be Fitted in the KR-6170 & certain alterations made. You'd be upping 70v HT Transformer to a 92v One, 22v extra HT. The JVC 5040 put out 35v Clean Sine uprating the 23v Clean Sine of the KR-6170 plus the Benefits of the Extra Power which were obvious using the KR-6170 into the SX-2500 power amp in a Blog just above, reasons for Thinking On This. Again Dear Reality Tells that Upping The HT Voltage as we did with the 25w to 45w oddity, the Bias will need Redesigning, be it Fixed or Adjustable. The Higher Power KR-6170 could be done, the Power Supply uses Resistors not Regulators, beyond one in the Preamp. To alter the Big Resistors to keep the Other Voltages for Tuner etc. But.. It's Not That Easy. The KR-6170 works on Two Secondary Windings, one 48v-0v DC (70v AC) & the other 27-0v AC (38v DC) for Tuner etc. To Find A Transformer to give the Higher Main HT, but then the Lower Voltage one to be useable too. The JVC 5040 TX works on 63v-0v AC (92v DC) & the other winding is 15v-15v AC with a centre Ground Tap which gives ±20v DC. Has 6.3v DC for Bulbs too. Potentially you may think it has 30v-0v if the Ground Tap not used. But Voltages tried like this don't work out as you'd "hope" as we've found before, Simple Maths doesn't always give the Right Answer. The 'other winding' needs to be 30v DC in use. The 15v-15v AC give ±20v on the Circuit. A TX output using a Centre Tap gives 15v-0v-15v, in trying one once with 32v-0v-32v, without the Ground Centre Tap it wasn't 64v, it was only a 32v single rail voltage. Theory will explain why, the Ground Centre Tap gives a Higher Voltage, in a similar way Valve Amps use a Diode as a Voltage Doubler. Two ends of the TX winding with a Ground Centre Tap play Voltages differently. The Conclusion is that the +92v HT can be used, but the ±20v would only be +20v without the Centre Tap. KR-6170 Second Winding needs 30v for Reverb Drive which is a Power Amplifier of sorts, 22v & 15v from that 30v for the Rhythm Generator which are Germanium Designs that are best not messed with, some Germaniums are limited in spec. -20v to +20v is in theory 40v...?

Voltage Doubling In Power Supply Circuits & Finding 'Hidden' Higher Voltage.
This is Familiar in Valve Amps, the 1965 Rogers HG88 III & 1963 Trio WX400U use this. Looking at the Trio, it uses the "Grienacher Circuit" as you can see drawn differently on the Wikipedia page for "Voltage Doubler". There are other versions, this one in the Trio is known as a Half Wave Doubler. It takes 145v AC & makes it 360v, allowing for Load Losses in the Circuit, Maths says 145v x 1.404 x 2 = 407v DC. It Doubles the Voltage if Halves The Current in the Power Rating way. 260mA is enough to drive 4x EL84 which need 65mA each if there are extra circuits on this 260mA draw, making the 12w EL84 only rate 10w on the Trio WX-400U. You don't often see the Amps a Transformer can offer on Vintage Circuits. The Idea looked at to see if the 20v DC from 15v-0-15v centre tapped JVC 5040 transformer could doubled to 40v. It Could, but the Current will likelly be Too Limited to give good Results. Hidden Extra Voltage? Sometimes an Early Transformer can have an Unused Secondary Tapping, the WX-400U actually did, so to make certain design features on a Higher Voltage was possible, by combining Two Windings. The fact the Trio WX400U had a 'hidden' extra winding is probably unique, resulting from a Design Change or more likely just use a Previous Transformer & not use One Winding. We have the Goodmans Module 80 Transformer still, an open chassis design, if sadly not thinking to keep other Parted Amps Transformers, often the Multiivoltage block is trapped in casing. It has the Multivoltage block & has only the Used Secondary Windings, HT & Bulbs. There are No Extra Ones. Another Open Chassis TX is the Akai AA-7000 one, there are No Spare Winding either. This suggests you'll be unlikely to find a Hidden Extra Voltage beyond the WX-400U. The 1967 JVC 5040 TX on the desk, it has a Metal Case with 4 bolts, so why not unscrew & see what's inside. Here it's like a more Modern Custom Mass Produced TX, with the Wires Connected inside the Windings, not to a Tab with Voltages marked as the WX-400U & AA-7000 are. There probably are No Other Amplifiers with the Hidden Extra Voltage than the WX-400U seems to be the answer here, but worth finding out. The amp version, the W41(U) has an extra marked Tapping if no actual Tag for the Tapping. WX-400U one is a Design Change just left there. What A Shame.

1969 Arena T-9000 75w Receiver From Denmark.
As far as we know, there are Only Three Receivers of this sort of Power, the 1967 JVC 5040U at 75w, the 1969 Pioneer SX-2500 at 72w & this Arena T-9000 at 75w. There are some Amplifiers & Power Amps of this Power & Higher, ones like the 1965 Mattes & other Power Amps, as well as PA Amps for Guitars etc. Arena T-9000. We've seen this in the later months of the 1969 Hi-fi News & it's in the 1970 HFYB for £303. A Customer found a nice one online, but didn't get it likely for Posting Issues as some sellers don't know how to Courier goods. A Shame to not get one & as of Dec 2023 to see HFE now has the Circuit Manals that it didn't have before & having a good set of Photos showing the Insides, Time To Blog this one as it's certainly interesting. The Manual is drawn like a Bang & Olufsen manual like the Beomaster 3000(-2). Here the Transistor Icon is a little non-standard, a 'Cross' with an Arrow is confusing, looks like a FET if they're not. To look at the Circuits to make sense, the Arrow is the Emitter, the 'Other End' is the Collector & the Horizontal is the Base, with only one side connected. Will have confused many, why not draw it as the standard way? Electrolytic Capacitors are shown in a " -] " way with the line the "+" & the ] the "-". Film or Ceramic Capacitors are just drawn as " | " on the circuit line, again not very understandable. This thoughtless circuit diagram will keep the Amp Unrepaired as few will understand it. Even a Zener Diode has a non-standard icon. Once the 'stupid' is understood, to look closer. This is a EU made amp & often these are made with TV grade components. Recapping in any way with Higher Quality Modern Electrolytics is likely to bring up Problems, if the B+O Beomaster 3000 was fine to recap. The Design is a little different, maybe to overcome this, but to never kmow until you try. Inputs go into a 'Transmodul' which is an odd name in these times. These are the Rectangular Plug In Boxes, on an 8-Pin Valve base from having an Arena years back, even after 20 years in the early 1990s the Plug Ins were aged & the Aluminium Controls had greyed as not lacquered. Remember it needed a lot of servicing to get it working again. T-9000 schematic only shows the Plug-In Modules, but doesn't show what's in them & lookinmg at HFE it's all they have. These Modules contained Transistors, Resistors, Capacitors & Diodes, like a Mini PCB so need detailimg. The 'Aux 1' one may be a Buffer Stage like B&O used, though it could add gain as the Heathkit AR-1500 did & have a preset to set Gain. Other Inputs for Phono & Microphone have a Preamp crammed in the tiny 'Matchbox' size units. This lack of info may later be updated, if getting one working alreasy seems quite a job. Preamp-Tone Board. This is the large 'T 76' board with Tone plus Low & High Filters, 7 Transistors per channel include Buffer Stages. A lack of certain features is where this could sound Gritty or have RF issues. Circuits look decent & from remembering the smaller Arena from the early 1990s it sounded decent, as knowing quite a few amps by then. The Reliability was the problem though, the Plug-In boxes were not connecting too well, if that was then. "Chuck It Then" said the Owner, we'd only taken it from the Shop to try. Power Amp. This is all Ditect Coupled, no Capacitors in the Signal path if the Preamp has several. This shows "M10" resistors, looking at others to see '3,9', '180', '4K7' & '18K' can only mean "M10" isn't '10M' but '0.1M aka 100K'. Again they just add confusion if you can read the resistor itself. Means it has '100K' as an Input resistor, that can't be right, or could be a Typo as another 'M10' used makes more sense. Again the lack of certain features where there should be is a bit of a worry, having tried other EU amps, it will be an issue. The Transistor Numbers are Obsolete 'RCA' numbered ones, like '40410' which is a 50w output transistor as a '40409/40410' NPN/PNP pair for the Driver Pair with '40411' 150w 30A or '2N3772' outputs. The Power Supply outputs ±44v & is on 6000µf 60v main Capacitors. This is equal to 88v on a Capacitor Coupled amp so can be 75w as claimed as 75w RMS both channels played. Amp has Two Main Power Supplies, one for L+R plus the Preamp-Tuner one working on +60v. Photos of the T-9000 we have show a one piece unit looking like two units on top of each other, this is how it opens up like a Clamshell. The Front Boards are Tuner & Pre-Power, with the Power Supplies at the back. Inputs via RCA Phono sockets duplicated as DIN as B&O did at the time. Speaker Outputs are DIN if also as Three Screws, L+R plus one for Ground, all very small risking shorting. Not a bad looker, some lettering a bit oversized, Tuner Window on a fascia top edge & basic looking meters. Like most EU gear it uses Axial --[ ]-- type capacitors. Photo set doesn't show the Pre-Power board. Output Transistors are on the rear panel under casing covers each side, as one missing these found online reveals. Hi-Fi News Dec 1969 Review. This gets a long review where they are overall impressed with it. 75w rated they test at 92w, if generally just slightly more current can boost the 75w when Clean Sine will still rate it 75w, why we don't bother testing the way Hifi mags do into a 8 ohm resistor. They do tell of issues they find, Clicks & Plops in use changing Buttons on Functions & Filters are found in other amps too, later design usually hid this with more Buffer stages. One worrying one is "Hum" that was slightly audible & could be heard in quieter Music, as in you'd hear it watching TV without loud soundtracks. They don't say if Hum in Audio from Poor Grounding, or Mechanical Transformer Hum. But to see the Square Waves that HFN recently started adding, 1kHz is a little rounded on the departing edge, a Bass Limitation. But the 10kHz 'Square Wave' is awful, saw tooth-dog tooth shape very rounded showing it's a Soft Dull Treble to be that poor on 10kHz, suggesting it's well tamed to cover the lack of certain parts. There are several reasons why & to Upgrade this would be a tricky one for sure. We've found Japanese Hifi can give a very strong knife-sharp treble, if the USA amps we've had recently roll Treble off quite heavily as the sound matches the poor 10kHz Square Wave. These USA amps use the same EU quality or TV Grade parts. The reviewer mentions this, but doesn't seem to Understand Hum plus Limited Treble is just not very good. Our Verdict. A EU made amp this early does bring Risks as said above. Quirky looks have appeal. Seems a Rare one as the Manual, if ever found much before, does complicate things. One worth trying, if Care Needed & probably way beyond most not to Wreck It. To Upgrade Hum & Limited Treble we've done on Amps before, if it can take Ages & often not be any Idea you've encountered before. For a potential Customer rebuild, having researched this now, to Warn it'd likely be a tricky one, as EU Hifi often is. Arena were a popular brand 1967-69 in the UK as many shops stocked their Midprice gear, soon sold as Bush-Arena if the T-9000 a Hede Nielsen product distributed in UK by Highgate Acoustics. Bush-Arena soon just became 'Bush' who were more a Budget brand into Radio & TV. Prices show unease on this one, £150 to £300 if lots in less main countries suggest it wasn't a seller & sold off elsewhere.

February 2025 Blog

Buying 240v To 100v Step-Down Transformer.
The Answer as we found below, is Forget New Ones, look for Vintage Ones. The 1962 Luxman Valve Receiver needs one. The Pioneer ER-420 is rated 155w so to 'hope' a 200w one would work & be reliable for Hours Use. To see New on ebay a 110g weight 240v-100v "Yazawa HTDC240V1000W Step Down Transformer AC220V-240V to 100V 1000W", are they having a laugh? 1000w 1kW use on that? It'll be some Switch Mode Converter device, not the 'Old Fashioned' reliable Transformer with Primary & Secondary Windings, as on the 240v-120v one we use on USA gear. That is marked 110v yet outputs 120v as it just halves the Voltage, to Input 220v you'd get 110v, but there's a lack of info told on these things. The Yazawa one on sale a lot on ebay at prices £55 to £70 with about £25 shipping from Japan. Not seeing Feedbacks on these, if Amazon has these & as Suspected, they are Rubbish that will Damage your Prized item. Switch Mode Power Supplies first around in 1979 on that Technics Mini System & it involves High Voltage Regulators & High Voltage Capacitors, much like TV & DVD uses today. Note Hifi still has the Transformer, if there will be many varieties of Power Supply. The Fact if we used the 240v-100v Step Down, it'd get Hours Use. The Usual 240v-120v black box one with the handle & orange light switch gets a bit warm, but if kept in open air it's fine. These Ridiculous 1000w 110g weight items will have No Heat Reducing Design. They say you can run a Kettle or Hairdryer, UK ones can be 2-3kW if maybe Japan made ones are much less & of little use. Avoid these modern devices, they are not for Hi-Fi used for jours. Amazon Reviews quickly show "Stay Away" & if you really want a 240v-100v Voltage to get a Transformer unit or possibly a Variac could give the 100v voltage, if a Variac is a Temporary Use item. Low Reviews tell the truth on Amazon, one said the 100v was only 82v so to assume it drew excess current & ruined their Amp. Amazon has a 117v to 100v "VCT VT-1000J" that's a 1kW one to see as a trusted type of Transformer unit, USA to Japan voltage. It says to get Double to 4x Wattage to cover Spikes, the 200w one drawing 155w wouldn't last long. But Why no 240v to 100v of this type? Because there is Litle Demand. To see Higher Power Amplifiers offered on ebay, to Ask Them what they use. Sadly the Japanese market keeps things very Secretive, even in the later 1960s it took UK Distributors to make Good Sales on Pioneer, Sansui & Trio-Kenwood. An Oct 2024 question to one with a Japano-ony Yamaha CA-2000 just gets a smug unhelpful reply, not even offering any soloution to a buyer. A 100v High Power item is seemingly Useless in the UK, the modern 240v-100v Step Down TX are for low power items, if to a point of 'why bother'. If they want Sales a clear solution must be offered. Resistors Dropping Voltage id Dangerous, like that 1979 Technics Mini system pitting 240V AC Direct onto a big Resistor. Do 't Do It. The only Solution really is a Custom Winding of the old TX to suit 240v. Having tried to get the 1966 KLH 27 receiver rewound, today the TX Makers haven't got a clue about Custom work. You'd need to get the right 'swg' thickness wire & know the Turns of wire needed & have it fit in the Amplifier. Any Japan-only 100v Amplifier offered sadly is A Con to unaware buyers as it's Useless in the UK. The Mysterious World Of Japan Electronics is mostly for the Language barrier & generally Google doesn't give much Japan coverage to UK readers. We had a Customer, the Sansui AU-G90X one, who used a 1990s CD player via the front Headphone socket if the Volume Control had worn out. He managed to source one from Japan & even got us an early JVC amplifier manual. Maybe a case of 'Who You Know' if mostly the Language barrier. To ask another with a 100v Amp, it seems Transformer winding no-one commercially does, as Wire SWG ratings are Custom in Transformers. There could be Specialists able to work out SWG ratings, Power Ratings & the Amount of Turns required, if it seems sizes of finished product might not be what you want. The fact UK can't find 240v-100v Step Down TXs doesn't mean Japan doesn't make any, but try find anything online. UK buyers should Avoid 100v Japan items as they are Unusable. But... A 240v To 100v Step Down Transformer is Buyable. Didn't see any on ebay as of typing the above, but Feb 2025 after having taken the Lux HQ32 off ebay, to find there are 240v-100v 600w or 650w units available. These are Used Older ones. Oddly the one we bought at £40 then others £110-£160, as Random as buying anything Vintage, as with the Pioner ER-420 tuner valve, none for ages them some appear. To get the Lux Rebuilt, only just done the 1964 Sansui 1000A. Bought HQ-32 Mar 2024, find 240v-100v TX Feb 2025. 600w suits like the more typical 240v-110v (120v) ones for USA amps, 200w amp allowing 600w for Mains Spikes is the usual idea. There Is A Problem with ours. Turning the Switch off knocks the Circuit Breakers, the Property ones faster than our Plug in one. Maybe it needs updating or repair, to look inside the 240v-120v one. In darkness only to use the Phone Torch to reser. A 600w TX 'bouncing' a fault isn't one too reliable.

Getting A Vintage 1970s 240v To 100v Step Down Transformer.
These are Vintage Items, not made new, We'd not trust those small 2000W ones probably working on Switch Mode Transistors. The Unit to buy is one lilke the typical Black Plastic Box USA to UK Voltage ones for about £40. 240v to 120v if you read it, just a 50% conversion, depending if you use it on 220v or 240v to get 110v & 120v, based on the idea 117v is the USA Mains Voltage at 60Hz. Step Down Transformer 'Nissyo SDX-600' made by 'Nissyo Industry Co. Ltd, Japan' shows how Unknown Japanese Electronics can be. Metal Cased shows it's Vintage. Nissyo founded 1967 & still going on searching online. Having asked ebay sellers what to use 240v to 100v, they won't tell or even suggest you look for Vintage ones. This sort of Secrecy & Lack of Selling Techniques is why the Fist Japanese Hifi in UK had no UK Distributors & wasn't trusted, until Trio-Kenwood & Pioneer got UK Distributors capable of offering Service & Guarantee work. The unit has an old 'Sainsburys' rubber plug with the L+N pin shielding & no Barcodes anywhere. Probably dates it to about 1978-80. Heavy Unit, like the 240v-USA voltage ones, so it has a proper Transformer inside. Probably was Lab Kit as old tape traces like from a large 'Dymotape' sticker remain & will clean off. The 220v-240v switch underneath was set to 220v so likely a EU used item. These seem Rare & do turn up pn ebay as does most Rare stuff, if not seeing any looking several times then seeing a few. Power Switch lights, reads 101.1v on the 2 Pin Blade Plug Socker. Has a Power Indicator with segments to show 100w-600w if '600w' only told by the SDX-600 model number. 1962 Lux(man) HQ-32 Receiver been waiting 10 months for a 100v supply, we have tested it for Voltages on 120v Mains to check it did at least Power Up if needs a Rebuild for usual aging. Reads 20& over with 120v & it'd probably work if not so well on 120v, things like Valve Heater 6.3v reads too high, but the 20% extra voltage pushes the Output Valves 305v instead of a likely 280v. Over-Voltage isn't Recommended for Use of any 100v item. It will very likely not last too long & a Safety Risk is possible. To Test the HQ-32 but leave it until whatever turned up, rather than try to get it to run on 120v with alterations. No Interest on the Lux HQ-32 on this site or on ebay shows how 'scared' people are of some Hifi. The fact it's the First Luxman Hifi Receiver in Valves from 1962, one so Rare not even one Japanese Hifi site features it. There is an element of 'pathetic' on a Rare & Complete amp getting no interest, probably got about 100 views on ebay over 3 months, did put UK Sale only. Where's the Collector Interest here? Fate wanted Us to Rebuilt it by Giving us a Bargain 240v-100v TX. There really aren't many capable of Rebuilding Valve Receivers, ones we've seen don't do it like we do. The UK buyer we got it from paid under $100 for it on a Japan auction plus about $300 delivery. We've Cleaned it Up, Tested it & Repaired the Front Panel as filler inserts to hold the Fascia metal strip the glue failed, leaving loads of Pieces wonderimg what they were. Fate sold it to Us. Will it be Any Good? Ours was set at 220v underneath, switch to 240v easily, suggesting it was used in Europe & as Lab Gear by Sticker Traces. A Test Sticker dated 2013 shows UK use yet not set to 240v isn't too clever. Reads 101.1v AC on first try. Nissyo SDX-600 & SDX-600U. Search the Model Number & these are online for about £150-£180, ours at £40 delivered a Bargain. No Japan 100v-Amp sellers would tell us of these, but they are around. Looking closer, the Nissyo SDX-600U is actually the one they have, a 110v-120v USA "U" version. The 220v-240v one is Rare. On Searching a while back, to see the 110v-100v version at high Amazon prices, suggesting you'd need a 240v-120v then 110v-120v one meaning Two TX Boxes. This Info, like a lot on this Site, you'll not find elsewhere, but We Research Things. Inside is a large metal Transformer, 600w size like the Yamaha CR-2020 one. One 0.3ohm 7w Resistor & a 10µf 16v capacitor on the Meter, an orange 'Elna' like Pioneer & Marantz used in the mid-late 1970s, Also has an older style Potentiometer more like a 1960s one which dates the unit more to Mid 1970s. Needed Servicing. What Vintage Electronics doersn't? Without anything plugged in, it tripped our Circuit Breaker always on turn-off. Now it's fine & Circuit Breaker stays on. To realise why it was a Bargain & 'No Returns' is the age-old game of 'Seller Knows But Won't Tell'. No problem for us beyond Darkness twice as also the Property Circuit Breakers tripped.

What To Do With The 1962 Luxman HQ-32 Hi-Fi Receiver.
This one has the Circuit Diagram on the Base Lid, Scan it up to make it readable as it's very tiny. A more Used amp could have this Incomplete & the Model Number Badge on the rear could easily be Missing as just glued on with the glue drying out. Odds Onwith ours to know Model & Diagram. No Components Numbered so it's Your Skills in Working Out what is what. To be able to Check Voltages on a 62 year old Valve Amp is probably Rare, as the Capacitors will be long dried out & certainly not to trust to use, but up to you if you trust it to Test. To find out "What Doesn't Work" & replace parts to at least get it Running. Ours now with a few parts replaced shows a decent HT & the Bias reads, without the Outputt valves in yet. To now put the Valves in, are they any good will be found out in the usual ways & to put our Headphone Box on the Speaker Outputs to make up for no Headphone. Going Blind into any Amplifier needs care. You might be lucky & get it playing Music & Tuner on first try, if usually one this old will show it's age with Hum & Vagueness. In Switching On with all Valves in, the gassed 12AX7 (ECC83) replaced, only some Heaters work, 2 of the 4 output ones don't & not all the Tuner Valves do if the Tuner Front End ones with bigger valves do. The Output Valve that glowed Red is one of the Working ones, so to find Heater problems. Get all 4 outputs Heaters going eventually. Headphones in, one channel Hums. Sound is 'there' on both Channels, the Left side with the Hum no Music, if we get FM playing set in the 88-90 range which is Radio 2. Dial shows 76-90 for Japan, it could be adjusted to fit UK use perhaps. It's Rough on Valves, needs more Servicing & Use at least. The Input Sockets take modern cables. But It Works. To Read Voltages now it plays to understand it further. How Many Years left unused until the Japanese seller tried it? Smoker's amp shows inside top lid blackening, probaby used it 2-3 years (or less) until t he Sansui Valve Range appeared 1963-1964 or the first Sansii transistor ranges by 1965-1966. So that's likely 58 years not used, not used that much & both front Bulbs work. One meter dosn't move if we know why to fix it. More Servicing gets it playing aux input, Left side low volume if Right side louder. Always good to hear it "as near original". It still needs much more done, to hear it plays Music well enough to bother doimg more. Treble & Midrange, mostly from the Right channel, seems of a Hifi Nature like the 1964 Sansui 1000A was. Hum quite loud on the L if the Phase switch quietens it a bit. Appealing looking amp, just One Torch Bulb in each Tuner window is a bit dingy & no meters light. To get it to this point more Luck from one not much used. To get it to 'Use Daily' is probably likely, but the Amount of Work involved. 473mm wide amp allows the two Tuners & it not being cramped inside. 1962 Tuners without extra features & pre MPX Stereo in one unit. To try to find the fault on the Low & Hum Left channel, instead of just rebuilding. To find what actually fails. The Valve glowing Red doesn't seem to have damaged it, only recently found bad & not used so it survives. Next day the Fault Found, it uses the 1959 'Mullard' Power Amp design.. Keep it playing & it's still aged with a bit of variance to settle as it 'wakes up', For a 1962 Japanese Amp, one of their Earliest, it takes much of what the USA Stereo Receivers use from 1959-60 with some strange design & "why did they put that there" thoughts. To hear it 'Near Original' matters. The "MFB" circuit, claiming to be 'Motional Feedback' from a Speaker, is really a sort of Loudness feature cutting the Output Volume & allowing the rear pot 'Boost' control to increase the Lower Bass within the Gain Loss. Gimmicky, but the 1968-70 Sony STR-6120 uses a similar Speaker Boos switch as do some McIntosh. Plays L+R with L side louder, Hum quite obvious playing both Channels, so main caps need the rebuild, the Multicap Cans. To order more parts therefore.

Headphones Compare. Audio-Technica ATH-M50 (2013) -vs- ATH-M50x (2023).
Bought the M50X a while back as Blogged Aug 2023. Not played them since as the 2013 M50 managed to solder the Wires. Did By New Bits to recondition, but never bothered as thety worked & replacement Ear Pads gets them better useable if Headband tatty & the Fixed Wire goes hard over time. On playing the M50 for a session, try the New M50X, in Feb 2025. The Test took only a Few Seconds, the sound was Not Good. Basically the Same Bass & Treble, but the Midrange very reduced making it sound Unpleasant. Much Nicer as New & more solid with the A-T real earpads. Tped this & try it again. Bass back -3 sounds better but the Upper Midrange is still Recessed as in not Flat & Neutral, when the Amp being played sounds right on Tannoys so it's the Headphone. The Bass is increased as the Amp Background has a More Bassy Hum with nothing playing. The old M50s the amp's background noise is one of the quieter ones & isn't a problem. Not to want to Upset Hearing by playing a Very Unnatural 'Created' sound, back to the old M50 & they sound right again. Reading Reviews of the M50X a few years back, others said the M50X was different to the M50. To think it's a Case of Running Them in as the M50 needed it, the large Reduction in Midrange that sounds like the 1kHz are is about 10dB down, rolling from 500Hz to 2kHz, a large difference. Usual comment is "What Idiot Thought This Was Better", to realise it's what they are using. The Mobile Phone 'sound' is limited & a more Midrange sound so it sounds like it's Made For Mobile Phones which is Severe Dumbing Down. The Difference in 1992 Tannoy 609 to 1967 Tannoy 15" Lancaster Golds is not so dissimilar. The 1967 Sony TA-1120 sounded lousy on 1992 speakers as on the Loudspeakers page. The Dynamite in the M50s is the Driver & a well used one in good condition. But they look Glued Into the plastic frames. Precious Parts could be reused, but the very fine Enamelled Wire is a tricky one. To take both apart more & try further, another time. But risk of things not being quite the same, the previous TiVo has the same power ratng if the plug on the end is different. Be sure the older one is better quality, the current TiVo keeps messing up when 2 or more shows record, the start takes more power & makes the earlier show still recording 'Stop' as it can't play through the Bad Part. A Little Strange In Use?. Brings up slight amp noises on the Left Channel on some amps. Turns out 'a little servicing' needed. In swapping around a few week's later, the M50X is a more upfront sound, leavi g the M50 a little 'soft' on Lower Treble-Upper Midrange. M50X suits the Tannoys better. Started playing up again & further needed, these are 2022 dated, why does it need any work? Beware these microscrews innards are to trip you up & break things, to note how (cleverly?) it fits together. Of course you'll have a wire come loose. Ours works fine now. If yours is in Guarantee, take it back, opening the Can & fiddling witrh the Earpad is not easy, maybe Mobile Phone repair shops don't see these to know the Pitfalls.

Later Trio-Kenwood Before & After They Used ICs: KR-7070 & KR-7400
One of the Better Hifi Brands, their TK-140X is their First Higher quality one, the earlier Transistor ones were not quite there yet. Their ranges go KR-x200, then KR-x400 then KR-x600. By the 1974 era KR-7400 at 63w the Power Amp is still All Transistors if the Phono & Pre-Tone are ICs. A 'RC4558T' is an Op-amp still findable on ebay, 8 Pin one with 'JRC' on usually & very cheap to buy. To look at the Spec Sheets, these crappy things are just General Purpose, not Hifi ones as some like 'Burr-Brown' claim to be. Says they are Stable so will be tamed if seeing the Transistor Equivalent is Why We Hate ICs: It's a Double Differential & Class B Amplifier with 14 transistors, 1 FET & 1 Diode plus Resistors & 2 Capacitors. The KR-7400 Tone-Pre needs Three of these awful ICs, used as L+R making the 6 (half) ICs on the Diagram. The Power Rating for both sides of the IC is 60-200mW & uses just 2-6.6mA which is a little Jaw Dropping compared to what a Trio Preamp with 4-6 real Transistors can use. It's little better than the early Germaniums used, needing 'Creative Circuitry' to compensate. Reality is the Soundcard we use has ICs & runs to Line Level, if not having the extra Tone gain. KR-7400 gives ±10dB Tone & Noise Levels are 70dB on Phono & 90dB on Aux which is like a Transistor pre can do. The Power Amp being the next range to the KR-6200 we have isn't that different, if the Protection Stage is Per Channel, not for Both Channels. Still using some Design going back to the First 1965-66 Trio-Kenwood Transistor designs. KR-7400 Power Amp Good, Preamp as ICs a No-No. The 65w KR-7070 is one we looked at on the 'Other Amps' page if No Clear Circuits then so with the Unusual Numbering, it's got Forgotten if we've had better Manuals since 2018. 1970-71 receiver there is the KR-7070 & a later KR-7070A. KR-7070 is a 65w amp after reading the many Power Variations that mean nothing, 110w at 4ohm one channel driven is no better than 300w at 4ohm Dynamic Power. Has Auto Tune Tuner to compete with a few 1968-69 Receivers (Fisher & Pioneer) & a "Boost Amp" which is a 'Presence' control that Boosts Midrange 1kHz & Upper Bass 400Hz to +6dB which will Sound Awful, why bother? It has Loudness too, be sure some will have used both & Tone and thought it was wonderful. 'Boost Amp' is in Circuit always, adding Two Transistors. Pre Differential input as Capacitor Coupled as are other Trio Amplifiers. Some Cautious Design in places suggests the KR-6170 & KR-5150 were Earlier. Some Doubling & Tripling of Resistors is unusual, 3x10 ohm paralleled instead of a 3.3ohm resistor. Works on 100v HT on a 5000µf 100v main capacitor which is unusual too, a Capacitor is usually given a Tolerance, but here it's 100v on a 100v capacitor. "V + H" on the Rear panel is an Oscilloscope Output for FM Tuner. A few Oddities, the KR-7070 still is of the Pre ICs quality if not an easy one to find. The 80w KR-7070A is a bit different, still Capacitor Coupled. Diagram more like a 1972 style. Changes Protection back to a Single Circuit, now an 80w Amp. Extra Speaker Outputs, 5w Mono Speaker Output, looks quite like the KR-6170 Jumbo at the back. '1971-9' code on the Manual. 80w if still on 100v main capacitor. A Relay on the Power Amp inputs is the Protection Muting, if still a Pre-Differential design. What's Different to make it 65w to 80w if it doesn't look much different to the KR-7070 earlier one. For 100v HT 80w seems more likely than 65w. The 'Presense' is now part of the Tone-Pre Board. A Confused Pair the KR-7070 & KR-7070A. There were no 8080 & 9090, they are Sansui numbers. Later Trio-Kenwood KR-9600 with IC output blocks are best avoided. KR-9400 is All Transistors on the Power Amp, sadly Preamp is ICs as is the KR-7400. 120w on Doubled Outputs with ±55v HT. Interestingly the KR-9400 finally changes what stayed continuous since the 1965-66 amps, values on certain parts. Not to say which as it gets 'amateurs' thinking it's better & go wreck a good amp. A Big Shame about the ICs in later Trio-Kenwood, but they Just Followed Fashion.

Highest Power Transistor Amplifiers & Receivers By Year 1965-70.
This is going by the Hifi Yearbook data as on out Two Pages plus others that were around if not always in the HFYB. A little difficult as they quote 'Music Power' & other confusing ratings, so to Check them via HFE info. Transistor Amps started in 1962 with Germanium 10w-15w ones. In the 1960s the Receiver was The Higher Power item compared to Amplifiers often being much less power as the Top or Only model. So only The Highest Power as Amp or Receiver matters. In the Earlier Valve era, the Amplifiers as a Pre & Power Unit could rate high as with Westrex cinema amps & the Radford ranges. 1965/66 brought the 50w Sony TA-1120 which only was talked of in HFN in 1967 as the 1120A arrived. Sony TA-1080 a 30w version. The Mattes SSP 200 another mentioned in HFN of about 50w rather than 100w as works on ±45v HT. Fisher TX-300 is 36w. In Receivers the Sansui TR-707A is rated 25w but oddly hides a higher power, perhaps by design. 1966/67 brings the Akai AA-5000 that's around 35w & later the Akai AA-7000 receiver of 40w. Sansui 3000 receiver is 45w. Pioneer SX-600T is 25w. Braun CSV1000 is 55w. James B. Lansing with a 40w power amp SE400SE. Sherwood S-900 40w. Fisher have a few Higher Power Receivers based on updated 1964 ones. Pioneer SX-1000T, SX-1000TA both 40w if rated differently. 1967/68 has Coral A707 at 35w which may not be a real 35w one. Dynaco Stereo 120 35w power amp. Vortexion pro amps range 40w to 200w of some type of rating not RMS. 1968/69 has the 'beloved' Quad 33/303 pair at £45. Knight Kit has 34w ones. Leak Stereo 70 35w a big seller. Quad & Leak were stocked by All The Shops as HFN ads showed. Nikko TRM 120 45w. Radford SCA 30 30w. Sansui AU-777 25w. Trio-Kenwood TK-140X 45w receiver out but not listed if the earlier TK-140E/U is, the white switches one as on our Gallery. Sanyo DC-60 30w receiver. 1970 HFYB named as just '1970' now. Several UK & Budget brands into Higher Power, but not ones that are our interest. Sony brings the 50w TA-3120 Power Amp. HH Scott 240-B 40w. Trio-Kenwood KA-4000 & KA-6000 30w & 45w. Luxman HQ 555 50w. Sansui 5000 50w, first of three versions. Sony belatedly arrive in HFYB with STR-6060FW from 1967 45w & STR-6120 at 50w, the most expensive receiver then.

TV's 'Salvage Kings' With An Altec-Lansing 9440A Power Amplifier.
This is an interesting show from 2020 onto it's 3rd series with quite a few changes, if Ted Finch is the Leader here. He's a real person & you can find him on 'LinkedIn' showing his job is real. The gear people leave behind in Demolition is quite amazing, they don't realise it has value or know where & how to sell larger Industrial items usually of High quality. To see S1 E2 they find one of these large Pro Power Amps just left behind, so to see what it is as it's beyond Domestic Hifi. The fascia says 800w, it's 200w Stereo if an 800w Bridged Monobloc with an additional unit says HFE. 56.5lbs from 1975. Clearly a PA Pro Amp & a little exciting for sure, but to wonder how "Hi-Fi" it is knowing cheaper PA amps are not of much quality. The Rear Panel in the Service Manual shows how Meaty it is, as many as 8x TO3 output transistors per channel with 6x TO66 driver transistors & cooling fans. For the Huge Power, the Circuits show it's designed to not cause Bother, as in it's Kept Tamed. Differential Input, Balanced or Unbalanced Inputs. Can't see any Relay & the Circuit would take some learning, but No ICs in this one certainly makes an impressive amp, in a 'Chieftain Tank' sort of way, compared to your Cute Little 20w Domestic amp. The Building it was in was an early Electronic Storage "Bank Data Centre" so this likely their PA Music System cutting no corners. Their huge Generator to cover Power Cuts equally 'Top Of The Range'/ What Speakers they'd use in 1975, they weren't left if again the PA Speaker market would provide. HFE shows Altec-Lansing didn't make much else, some early valve gear, a 44w "714A" receiver that's Capacitor Coupled so likely c.1970 if only one preamp in the 1990s. USA brand, odds are they aren't 220v-240v though as not in UK's HFYB. Prices on HifiShark aren't that much, the TV show sold it's one & 2 other units for $450. The "9440A" on circuits does seem to be 'Well Controlled' as a 200w/800w amp must be, a huge lot of Diodes in the circuit keep it Unconditionally Stable if perhaps Not Very Exciting beyond the High Levels. Seems all Direct Coupled beyond the Input, no Coupling Capacitors in the Audio which can make Repairs tough as Damage can spread. Has an obscure Darlington Transistor & SCR for 'Protection' if no Relay. What Seemed Exciting soon seems just a High Power Workhorse, prices don't rate it's Power in Hifi Prices. Ebay shows the Brand as more popular on Speakers, a non-working 714A only made $99 & is very like the Hitachi as we say below.

Altec-Lansing 714A 44w Receiver. Also 714AX Multivoltage from 1970-71.
Notes on HFE show this is a Multivoltage version too, to find the '714AX' would likely be tough. Front Buttons like the Leak 2000 from 1971. User Manual code suggests 1970. Photos of the inside show a Hitachi Code on the Transformer & it looks like other Japanese amps of the era, not USA built or with EU components. a 'Delta' triangle on the main capacitors seen before. Circuits are x3 Transistors for Phono including a Buffer, Preamp also has a Centre Channel Output not in the Preamp-Tone Circuit. Some unusual design in the Preamp with 5 transistors per channel including the Centre circuit. Power Amp is Capacitor Coupled, 9 transistors in total, design a little unusual. One you'd need to Hear, to wonder why they only made Two Receivers, this & the 30w '710A' that could be 1968-69. The '710A' does look like the 1971 Hitachii SR-1100 especially the back panel. Push buttons like UK Sugden & USA McIntosh Hitachi made two decent Realistic receivers as we've had before. At least Built By Hitachi so to expect a similar Decent Quality receiver, if you can find one. A few on HifiShark not making much, if earlier than their 1973-74 date.

The Huge Benefits In Servicing Electronic Gear.
Most never bother as they See It as a Waste Of Money because the Item still works. True it can still work but can be Way Short of It's Best. Reading what Faults people put up in in Hifi is quite shocking to us, they'll still keep using an Amplfier that Hisses, Hums, Makes Noises or isn't equal Volume both channels. It's like Running a Car into The Ground & scrapping it, ideas that were around before a MOT picked up on far more things, after all a Car is a lot more dangeous as you're sat in the thing driving at high speed. Hifi we use has been Rebuilt & Serviced, so it's not often an Amp can be used as Original on Headphones & much rarer we'd trust it on our Tannoys. To hear amps as Raw & Aged reveals those sort of Rough Far-Gone type issues, if we sort it out before using again, to not want to ruin it & sometimes not to use it again until Rebuilt. Computers Need Servicing Too. For life over the last few years, the 'Big Hoax' has caused long-lasting issues & you can see some people have aged more than Three Years over the last three years. Our Computer by the service dates inside shows it's actually older than we thought, but regularly maintained with New Parts over time, it's kept going. But it's been so slow, Firefox takes ages to start, Click on a .jpeg to open & it can take ages too. This humans can learn to live with as you're busy doing other things. In reality the Computer Needs Servicing Yearly, blowing out the Dust & General Servicing including Hard Drives. The Computer can be on all Day, not into Power Saving Modes as they just make things slow. So to service it & check it to a degree, not takinmg the Motherboard or Processor out, but checkimg visually like Hifi gets. No problems at all phsyically after the last Service Date being Feb 2020, just before all that Nonsense started. Typing this Mid Dec 2023 means it's had nearly 4 years sonce the last Service & was just getting annoying. Timing is the thing, so near to an Xmas few will particularly want, beyond a few weeks rest if they're lucky. Some connections look a bit aged, the Memory boards were all fine as was Sound & Vision. Computer may not be Windows 11 compatible, if who cares really, just more bloated junk & forever messing design around, Start Button in the middle? We still use Quick Launch that's well hidden, don't want anything more than Windows 8.1 gave. So What Happened? Started up quicker, a scan found some 10 year old 'apps' had unwanted things, not used them & that's another Computer issue, keeping Obsolete Junk, though be careful what you Delete as in any Tidying. Open a .jpeg was fast as it should be, Firefox opened much faster than often 1 minute wait. The Taskbar we keep on two layers, most of the last several weeks the thing resets back to one layer. Things like Websites forever nagging for Text Codes & 'Trust This Device' when it's the exact same one on the same IP shows Computer issues. This could be the Battery on the Motherboard, ours read a good voltage if Servicing needed. A BIOS/CMOS battery holds certain data when the Computer is off. To use the Computer more to see how it holds Data, why the Taskbar doesn't keep the height. So Far it's like getting a New Computer for how Fast it is again. Programs open much faster, Internet loads Sites Faster. Servicing is Maintenance, to see Cars on TV shows, nearly 100 years old or 20 years old, kept Serviced & Used is what Cars thrive on. 30 years in a Barn leave Cars often in very poor grade & generally 'dead' unless a huge amount is spent.

Where Upgrading Ideas Come From.
For all the Amps & Receivers we've had, to find some more memorable than others. Some have 'a lot of good' but other sections way short. No Domestic Amplfier will have PA Qualities & Without Any Dumbing Down, so to pick & choose The Best Of The Past in a Cherry Picking Way, of how to Imprive Circuits. To remember the Sound from one we had back in 2012, the 1975 Luxman L-100 & the 1967 JVC 5040U last had in 2019 after first getting in 2015. To see current ideas could better both is showing the amount of Circuit Gazing & Upgrades in other Amps. Trying Upgrades needs good listening & to use on Speakers for a Week to get used to the Upgraded Sound to then Compare back to different Amps then thought to be 'The Best There Can Be'. Of Course the amount of 'Best' gets more & more subtle. That One could fo with Crisper Treble, that one could do with Deeper Bass & to confuse then others could do with a more Precise Midrange. Using Stereo Music & TV to test works best, revealing Stereo Width & Depth Of Soundstage. Is it a bit Dull or is it a little Thin are Questions asked on Playing Music on Headphones or TV sound on Speakers. Play the same TV you watched earlier digging out the TiVo deleted files. Getting Better Sound as Advertisers claim FETs, ICs & all other new ideas is all nonsense when you can hear the Best Sounds from 1969-70 era Hifi, if it took a huge amount to get there. You've read of them before, 1969 Pioneer SX-2500 75w & 1970 Trio-Kenwood KR-6170 Jumbo 33w. Big Difference in Power if in reality both are fine on 95dB Tannoys. In terms of Power Ratings, it's only a Higher Voltage used that increases power, the Doubling of Output Transistors increases Current to make the 1971 Akai AA-8500 a 65w instead of 40w without the Doubled Outputs. Years Of Hi-Fi Circuit Reading reveals that the General Idea is 'Not To Give Them The Best Stuff Ever' like the "Back To The Future" line. Amps can have outstanding design but be Dumbed Down & Tamed to Hide It. Only by Questioning All You See can the Secrets be unravelled. The 'Ideal Sound' is an effortless huge soundstage with wide Stereo & Smooth but not restricted, Extended Treble & a Rich Bass. Imagine if Shop Bought Hifi was Like That, you'd play it Too Loud & cause problems. Generally the 'Sound' of the Amp is made in the Preamp, if the more Power Amps are compared, just reveals the Whole Amp from Power Supply, Preamp & Power Amp affects the sound. The Best Hifi is the Least Restricted, the Least Dumbed Down. Many Great Designs, but Never Just One Perfect Amp. The simple designs of Single Ended Triodes with 1930s Valves brings a wonderful but Very Limited Frequency Range. Those saying certain Amps are good for Rock, Classical or Acoustic Music generally have Substandard Hifi. Rock on rough sounding mid 1970s Pioneer suits some, thin overbright sound suits Classical more & Acoustic Music being so uncomplex sounds decent to some on these 5w-10w efforts that cluttered up Hifi Mags & Shops by the 1969-72 era.

Reviewing The Reviews: Sansui AU-777 Amplifier April 1969 Hi-Fi News Review.
This is the First Sansui Transistor Amplifier, the 30w AU-777 exists in "A" & "D" versions if "B" and "C" ones don't apparently exist. The first one seems to be 1967 with 2SC281 & 2SC650 early Silicon Transistors. This has the 'Tape Head' input as the HFN review shows, if by 1969 the old style 'Tape Head' input was obsolete as Tape Machines had their own preamp, it was for playing a Tape Head itself direct. The "A" version is simplified from a huge amount of Phono-Tape Head options as is the "D" which seems much the same, both with the 2SC458 transistors that often are hissy. There must be differences if nothing obvious as the AU-777 to AU-777a version shows. The AU-777 version has a strange "Prescence" switch that actually Boosts Bass in the main NFB Power Amp stage, like the 1968 Sony STR-6120 has for a Bass Boost. HFN read it boosts around 200Hz not the usual 'Prescence' boosting upper midrange around 2kHz. HFN says it has the usual L+R Mono output for a seperate Amp & another just for 200Hz bass, both of which were not of much use, if will have been for the USA Market for larger rooms. One design oddity is the Drivers pre the Outputs are both NPN, not the usual NPN-PNP pair. The 1967 Sansui 400 receiver used a Germanium PNP & this design avoids that. Uses a small Inductance on the Output Transistors, an 0.8µH not seen elsewhere as done differently usually. The HFN review by Reginald Williamson, Reg in other reviews mostly reads like the Specifications, telling you what it does. Not for the First time, Reg's Tests manage to Wreck the Amp's Output Stages making the UK's distributor do a long 380 mile journey to see what Reg done. They 'Don't Know' of course, soft lad damaged it somehow. Sansui are a very reliable Brand & we've had many of their 1965-72 models. We can see 'what it lacks' to have likely caused the bother & looking at the AU-777a design they sorted it differently. Beyond the Over-Complex Phono-Tape Head inputs, the rest of the amp is away from the 1965-66 Transformer Coupled TR-707A & 3000(A) designs, nearer to the 1967 Sansui 400 receiver we've had. The HFN review continues the waffling, saying the 'Tape Out' has No Buffer Stage which was the normal idea, though a Buffer on Tape Out we saw as worthy early 2000s making one for our Sony STR-6120. Review mentions the 1969 £110 amp was in the league of only a few Japanese amplifiers, to know they mean the 1967 50w Sony TA-1120A & 1968 48w Trio-Kenwood KA-6000 as well as the 30w TA-1080 & the Luxman SQ-1220 50w amp. You're buying an Amplifier designed for the more Advanced Buyer in North America, the amount of Sansui 3000(A) sold to USA via the Army & Navy Stores shows the market as we've blogged before. To suit as many buyers the Loudness & Filter Stages had to be included. Loudness was never liked by Hifi Magazines or Us past Teenage-early 20s when thick thuddy Bass was considered 'cool', it's not Sophisticated Listening, but it suits when you've heard that sort of sound in Nightclubs & Discos. The Filter for High & Low Frequencies was more a UK thing for gritty grainy UK audio, the 'devotees' trying to filter out Rough Treble & Rumbly Turntable noise seems a bit hopeless now, but a £110 amp could be used with a £12 turntable & £2-£5 cartridge on £16 speakers as was much Advertised in HFN at the time. Buyers hadn't got a Clue. Would This Review Give You A Clue? Highly unlikely it would justify why you'd pay £110 instead of £35 other cheaper amps of 30w could be including UK gear. The Review tells us the Square Waveforms ar 1kHz & especially 10kHz are unusually good, but The Fool wrecking the amp is Laughable to put in a review, but Our Reg likes to trash Hifi thinking he's Testing it, but clearly doing things very wrong. Review makes No Mention of Cleanness of Treble that Sansui do have, a good Bass, a Fast Lively Open Sound or any Subjective Opinion at all. It looks nice but may be a bit harsh looking visually to the Wife is as far as opinion goes. The tests show it puts out 31w at 7.5 ohms, when 8 ohm speakers are used by now. They show Square Waves into the notoriously difficult ELS Electrostatics by Quad, a design that Quad has to compromise it's own amps to play, they always show odd spikes in the waveform as the ELS is a horrible load some amps just won't play into. The HFN reviews until into the 1970s basically just rewrites the user guide & specs plus Oscilloscope tests few will understand without actually having used an Oscilloscope. They at least give a Real RMS Continuous Power Rating, 30w, not the Music Power nonsense that'd call it '120w' when it has no meaning in the real world. Looking At The Circuits. The AU-777 we thought a bit over-complex, the AU-777a with simplified design will be a better buy. Knowing enough Sansui, we'd buy either, if never found one & don't see the need to buy an expensive one from the USA, if it's certainly be a Great Amp. We have had the Very Overpriced 1970 Sansui AU-999 years ago to know the 1967 Sony TA-1120A was a better amp, both being 50w.

'The Repair Shop' Xmas 2023.
A New Episode without the tedious 'Distancing' nonsense & to skip thru Unwanted Slush & twee 'Secret Santa' stuff, the rest of the Show is still worth a watch. Here they have a 1990s-2020s Record Player, those 'Quaint Retro' ones that even 'Pawn Stars' show. These seem to have Sold Well & we've never seen one to know what's inside, if expect 1980s Music Centre-Amstrad style build. Here the likely 12v turntable motor power supply regulator board has failed, regulators & diodes possibly failed, nothing burnt looking, if no circuit diagrams so he gets a replacement different board & thinks it'll be the right voltages. This soon gets passed over suggesting it didn't work, but can't be hard to buy the same full player unit on ebay. Cramped board with several plugs, our Lad cuts one wires piece back to very short cut-off ends & solders them midway with no Heat Shrink even, why not do it properly & wire onto the board? Item shown working, if as with Electronics, be sure not much if it'll be the same one, swapping working innards to a non-worker as beyond repair. The Insane Mechanical-Electronic Cake is quite a find. Made of Meccano to have moving Cake Ornaments on top, it is a joy for How Clever the maker 'Uncle Fred' made it from scratch. They have Film of it from 40-50 years ago showing the delights of it working & certainly a mammoth task to restore. Maybe they've Bitten Off More Than They Can Chew on this one (cake) & how long it took we're not told. A Solenoid draws 10A meaning it's shorted so they fit a new one easy enough. But all the mechanics & drive belts, to melt together a length of Rubber Belt is the way & for Hifi Cassette & Tape, the join bump will never be perfect. It's why we avoided the Thorens Turntables as had enough of Belt Drives in the 1980s & early 1990s when you could still buy belts, today there are no NOS belts as the rubber will have aged. Rubber belts don't last long, they perish, go soft & extend in size, making them useless. When Belts were buyable for the exact size, a New Belt was a Huge Difference in Useability compared to the saggy old belts. Rubber Belts are still in many Vintage Cars, if that Market has a bigger Demand than Cassette Player repairs, to still have them made. Rubber Belts are like Chromed Sections & Bumpers on Older Cars, strictly Retro. Clock Builder Steve, he who sometimes looks like a Giraffe, made a circuit description to understand the cake's workings, to break it into stages to understand is how a Valve Stereo Receiver gets rebuilt, hours of preparation. The Cake works like the old Film showed if the difficulties not shown much as with things Technical, as it doesn't make good TV & hides the 'Magic' in rebuilding, save giving the difficult stuff away.