1973 JVC 4VN 990 AMPLIFIER

IN NICE VISUAL & GREAT WORKING CONDITION.

35W x4 plus 88W x 2. SERVICED & RECAPPED WITH UPGRADES

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110V-240V MULTIVOLTAGE. THIS IS A QUADROPHONIC 4CH AMPLIFIER OF 35W x4 CHANNELS. VIA THE "BTL" SWITCH IT RATES AS 88W x2 CHANNELS. WE READ THE OUTPUT AS 56V WHICH RATHER SURPRISINGLY PUTS IT IN A 180W RANGE. WHETHER IT REALLY PUTS OUT 180W WE'VE NOT TESTED, IF WATTAGE DEPENDS A LOT ON THE CURRENT CAPABILITIES.

THIS IS A TOP RANGE 4CH AMP & A GREAT LOOKER. IT'S A VERY COMPLEX ONE & AS 4CH FAILED BY 1976, ALL 4CH AMPS WE'VE HAD WERE LEFT UNUSED SINCE THEN, OWNERS NOT REALISING THEY COULD BE USED AS A 2CH STEREO AMP. THEY TAKE A LOT TO SERVICE & IT'S A 4CH AMP SO DOUBLE THE CHANNELS. BIG BIG JOB.

ON GETTING THIS, THE TRANSISTORS WERE HISSY & ONLY BY REPLACING THEM DID IT REVEAL THE "SEA" TONE CONTROL WAS NOISY AS DESIGNED BY JVC, CLEARLY THEY NEVER TESTED IT WHICH MADE THE AMP NOT SO GREAT. BUT... WE'VE REDESIGNED IT TO LOSE THAT NOISE & STILL HAVE A GOOD GAIN. NO-ONE ELSE HAS WORKED THIS OUT & IT INVOLVES REDESIGN IN SEVERAL PLACES, NOT JUST ONE EASY CHANGE.

THE AMP IS NOW USEABLE ON SPEAKERS WITH SEA-TONE GAIN, THE SEA 1KHZ MIDRANGE IS NOW HUGELY QUIETER & THE STAGE IS NO NOISIER THAN ANY OTHER VINTAGE AMP, IF NOT AS QUIET AS SOME LATER ONES, IT'S BARELY AUDIBLE ON HEADPHONES. ON 95dB SPEAKERS A SLIGHT BACKGROUND NOISE CAN BE HEARD. IT'S GREAT SOUNDING ON THE BTL MODE WITH VOLUME LOUD ENOUGH AT '3'. ON HEADPHONES IT'S VERY QUIET, BUT AS IT'S NOT SILENT ON 95dB SPEAKERS, TO PRICE IT DIFFERENTLY. IT'D SUIT 88dB ONES BETTER.

THE SOUND OF THIS IS THE DIFFERENTIAL DESIGN WITHOUT THE LIMITERS & DIODES MAKING THESE BRIDGED AMPS A MUCH NICER SOUND. CRISP TREBLE, SMOOTH MIDRANGE & A GOOD BASS. FAST PUNCHY SOUND. AS ORIGINAL, LIKE ALL AMPS IT WAS NOTHING LIKE THIS, THE POWER IN UPGRADES. ONLY TOOK 4 YEARS TO GET RIGHT, ONE OF THE HARDEST AMPS.

ORIGINAL OUTPUT TRANSISTORS, WITH THE SMALL SIGNAL TRANSISTORS ALL REPLACED TO LOSE THE HISS. DECENT PHONO STAGE. 4CH FEATURES AS THE FRONT SHOWS. A 4CH DECODER WAS A SEPERATE UNIT ITEM, NOT BUILT IN OR AN EXTRA.

UNIQUE DESIGN WITH ALL ON PLUG-IN BOARDS IS A LOT TO REBUILD. A TON OF WORK IN THIS, WE DO THIS AS A HOBBY & LEARNING HOW TO SOLVE THINGS IS PART OF THE FUN & ANNOYANCE, TO SELL AS IT'S FINISHED TO SELL NOW.

THE GREEN METER LIGHTS ARE NOW 12V LEDS TAKING THE DC VOLTAGE IN A DIFFERENT WAY & MATCHING THE BRIGHTNESS OF THE ORIGINAL AXIAL BULBS WHICH WERE 8V ONES & LONG OBSOLETE. NO FLICKER USING DC & AS ALWAYS A HUGE JOB TO GET RIGHT HAVING TO REDESIGN THINGS.

FOR SPEAKERS, ONE SPEAKER SET OF 4, TO USE CH1 & CH3 FOR STEREO OR 4CH MODE, YOU CAN ADD 2 MORE SPEAKERS ON CH 2 & CH4 THAT GO SILENT ON SELECTING BTL-BRIDGED MODE. 'BTL' USE MAY CLICK THE RELAY OFF, BEST TO USE THE 2-4CH BTL SWITCH WITH THE VOLUME TO ZERO & AFTER THE AMP HAS BEEN ON AT LEAST 1 MINUTE, IF NO NEED TO TURN THE AMP OFF. ON TURN OFF THE RELAY BRINGS A 'CLICK' AS SEEMS TO BE TYPICAL WITH 1972-73 ERA AMPS.

CONDITION IS GREAT, A LIGHT SCRATCH ON THE FASCIA TO RIGHT CORNER & NOTHING OF NOTE OTHERWISE, A "9" GRADE.

THE RELAY TAKES 20 SEC TO TURN ON, A LITTLE LONGER, BUT IT'S UPGRADED & REDESIGNED, THE VOLTAGES TAKE LONGER TO SETTLE.

A GREAT SOUNDING & LOOKING AMP, 1973 STYLING LOOKING 1990s EVEN. HEAVY AMP, SOLIDLY MADE, JUST A PITY THEY GOT THE 'SEA' NOISE WRONG, BUT OTHER BIG BRANDS DO GET DESIGN WRONG ON A FEW AMPS YET OTHERS ARE PERFECTION. ANY AMP DESIGN IS ANOTHER PERSON'S IDEA AFTER ALL.


A larger sized amp 422mm wide x 134mm high x 371mm deep if 395mm Max Depth inc fittings.

THE AMP ITSELF WEIGHS ABOUT 16KG

THIS AMPLIFIER HAS BEEN FULLY SERVICED, CLEANED, CHECKED VISUALLY BY TAKING APART, RUN IN FOR HOURS AS WELL AS USED BY US!

WHY PAY EXTRA FOR A SERVICED AMPLIFIER WHEN OTHERS ARE CHEAPER?

All amplifiers & receivers we sell as "SERVICED" means they have always been CLEANED, CHECKED, FULLY TESTED, FULLY ADJUSTED, USED FOR MANY HOURS and are offered as good reliable amps ready for you to use. We've sold over 100 Amplifiers & Receivers now & buyers are clearly pleased with the item they get! A Serviced Amplifier is a Reliable Amplifier & will have had any problems dealt with before we sell it. Our checking is way beyond a basic PAT test, each amp is taken apart & examined. We are Qualified Electronics Engineers with over 20 years experience of Amplifiers. All amps over 20 years old need servicing as parts need attention to work properly or faults, failures, damage, noisy operation and unreliability may be present. Any faults we can repair & our work is of a very high quality. On each listing we put at least 12 large clear photos of all aspects of the item including the insides.

This is a Vintage Electrical item. No Warranty or Guarantee is offered or implied but be assured we have Serviced & Tested it to a very high standard before sale.

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