JVC A-90B

Snuck

Active Member
Hello,

I'll do a review of the very few known JVC A-90B, an amplifier that was coming usually with a full system made for it which is usually very underrated but can be found at very cheap price.

It's a vintage amplifier made from 1982 to 1987 at the price in japan of 69 800 yen at time, which was quite in the top of pricing range for JVC. JVC stand for JAPAN VICTOR COMPANY, they simply splitted western and japanese company so if the western company would have fail, the japanese one would have remain but most of the bad words are coming from fact they take Victor as the upper brand, and JVC as just cheap products that japanese accepted to send us. It's quite uncorrect since we mostly got the same products most of the time, with same caring, if one checked both same version of a jvc and victor, they would know.

There are some versions of Victor's that were never released in their super version like the real AX-1100 (we have his lil brother named the JVC AX-1100 which is really a Victor AX-990 which I'll review later which is like 90% the same) and wasn't much sold, which can help understand why they didn't bother bringing the big brother.

Do remember that all I recommend to make check and repair all vintage gear before use, it's a bigger expense compare to the bargain u did and sometimes, they needed just a good cleaning but that's way better than having bigger troubles later. Always consider that repair price (from 50 to 150 euros usually or more or less the same in dollars) in the buying price to be sure not to have bad surprises. For speakers, depending on quality, prices can easily go further if suspensions are to be changed, that's why it's good to always use them under their covers, sound isn't really changed if at all and suspensions tends to last longer to my opinion.

The JVC A-90B is an amplifier named Dynamic Super A that JVC invented due to technological advances making components always smaller, less heat, less weight for same level of quality if not better. It's basically what happends to all the informatics, tv and so on. So, they claim they reached pure Class A through this design and way of fabrication without going for AB amplifier . Some don't believe it, fine by me, me I do believe it, I just sum up a part of the process in which they describe how they came to make a Class A without the troubles of size, weight, heating and product pricing without going for an amplifier AB or else which they clearly described as another way of amplification.

Therefore, this amplifier is announced as a 0.007% distortion for 85w at 8 ohms. This amplifier was mainly used with Klipsch RB-81 mk II which are very good at making hear any differences in a system. At first, the amplifier is extremly nervous, it's very hard to reach 1 out of 10 on volume, the sound level is really big. But I guess it's because of the Gm Driver system.. The Gm driver is a way to reduce noise by -12db since they demultiplicate the ratio. The result is clearer, natural sound, but only once the amplifier and this gm driver is fully burning in, it really takes a lot of time for it despite sounding good from first time in years. Otherwhise the Gm driver system just sounds like a sound reduction for evening listening or else. It's under estimated in the quality it can bring of the music : it can make a voice clear, thinking it's right in front of u, an electric guitar can have it's sound really well detailed, same for violions and others sounds. But it have one drawback, u lose in power what u gain in detail : because it shows the full amplitude of the moment or almost all of it, it's much more detailed, but it's as if u were missing informations before and now u here them, it's decomposing music without making it fully analysed, it's still binding it together in a way better sound.

The main problem of this technology I found is that it requires good speakers, on Klipsch RB-81 mk II, the result was good, better but lack of power tended to make them blend at time after a while, at least to my earing, but on Jupiter S from Tannoy, it was a different world, the sound was way better handled. I know they did a second version, improved of that technology on AX - 1100 which I just simply fell in love with but this version isn't already bad, it's really neet , entertaining sound, with very good back stage, it's really good amp but please, don't ask me why but just DO NEVER TURN ON DIRECT MODE on a JVC amplifier. It simply turns the sound from warm, glorious and enjoyable music, into a very neutral, very analysing, clear music, of course, it's still pretty but it's just the sound that turned cold, dead, it seems the female voices comes out of a banshee in compare and that everyone is dead, sacrifying their life for the sake of a music very sweet.

The very large range of frequency it can deal with helps to make a very nice stage of music, including a lot of details and the front made in alimuium block is really nice to se, have much more style than moderns amplifiers.. Buttons are stiff and reacts well, just the balance and trebles, bass controls are kinda hard to use, but I never had to use them, even if one day I tried by curiosity, it was making sound prettier but I found lacking of fidelity then, was too much in my opinion.


All in all, I don't say this ampli is top of his category, go sell urself to find one in the world. No, I say that JVC did a good work, a nice mix of very solid build, strong power (it really is a nervous one, especially after beefed with an amr fuse that made him seems like under steroids, so much I am even scared of doing the same thing on the top of the Dynamic Super-A line : the AX-1100, really change fuse of ur amplifiers!).

The main drawback of this amplifier is that the binding post are with spring hehe, so u can just use bare wires to my advice. In one hand, it's cheaper but it's not the best for big speakers, but honnestly, those amplifiers are powerful, so they won't mind feeding well speakers even if wire isn't as good quality as they would deserve. And it can still be changed by a good repair tech.

I say I love the natural sound, the power it delivers, even without the fuse, that the music is well restitued with some really solid quality of the components inside, look the size of the alimentation ! And the fact that Victor/JVC looked for new solutions to improve audio, making it easier to able due lower pricing without renouncing to quality. For that, I like JVC and it's constant looking for improvements where others brands could be more traditionnal even if they too, they got nice results. I also find JVC extremly reliable, cheap due to few people estimating them. All I know if they beat up some amplifiers or defends themselves very well with good systems. I don't wanna people to overlook JVC as forgotten brand that beats everything up, it's not true : they did all kind of gear with an amongst of quality based on paid price, of course low price mean low perfs, JVC isn't magician but I like the way they used and they did some very good gear that some companies could still beat I guess, but at which expense? It's always all a matter of price and several brands from Japan as JVC were very agressive on ratio price/quality. P_20171022_222739.jpgP_20171022_222748.jpg

Thanks for reading!
 
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