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JVC A-X3 review/manual

Anyone got a scan of the manual?

I've got the service book but not the owners manual.

£700....that's quite tasty!
 
Wow, listening via GRADO RS2s. The head amp is loads better than that I normally use, a Project Headbox II.
 
Looked at circuit diagram.... power amp interestingly redolent of Electrocompaniet but without the class A operation of course. Usual Jap naff idea of putting tone controls in the power amps negative feedback loop... ARGHH!
Phono stage looks pretty good and as is so often the case is built around parts we just can't obtain any more today (the most sophisticated transistors and fets for audio were the ones made by the Japanese around this time. Now that so much of the mass market is for digital, and vinyl is no longer mass market, they have been discontinued by the makers)

There is no headphone amp (a head amp is a very different thing to a headphone amp!!! I keep seeing the phrase head amp, where headphone amp is meant, annoyingly often these days!) and the headphones are powered from the main power amp via damping factor destroying 330 Ohm resistors as is the usual case for something like this.

Very well designed over all and in a completely different league to Naim in terms of design sophistication etc
 
Robert said:
Andrew, you're pulling our collective legs right? ;)
Click to expand...



No, honestly.

On CD its stunning, really a game changer for me as I've never heard CD sound so good.

On phono it's probably just a bit better than the NAIM.

It has a grip on the SARAS beyond the 135s.........never thought I'd say that.

It's staying.

I hope it doesn't go bang as Jez implies parts are unobtainable!
 
Arkless Repairs said:
Looked at circuit diagram.... power amp interestingly redolent of Electrocompaniet but without the class A operation of course. Usual Jap naff idea of putting tone controls in the power amps negative feedback loop... ARGHH!
Phono stage looks pretty good and as is so often the case is built around parts we just can't obtain any more today (the most sophisticated transistors and fets for audio were the ones made by the Japanese around this time. Now that so much of the mass market is for digital, and vinyl is no longer mass market, they have been discontinued by the makers)

There is no headphone amp (a head amp is a very different thing to a headphone amp!!! I keep seeing the phrase head amp, where headphone amp is meant, annoyingly often these days!) and the headphones are powered from the main power amp via damping factor destroying 330 Ohm resistors as is the usual case for something like this.

Very well designed over all and in a completely different league to Naim in terms of design sophistication etc
Click to expand...

Not much in that circuit that couldn't be satisfactorily substituted with modern parts though, should they fail which is very unlikely for the line and EQ sections.
The power amp uses nothing that can't be fixed with good comparable off the shelf parts today.

There's a thread somewhere on AK where the phono IC in the AX-1 had failed and it was possible to adapt the board easily to take a modern dual op amp, with better performance.

You'd have a dead A-X series running in no time in your workshop!
 
flatpopely said:
No, honestly.

On CD its stunning, really a game changer for me as I've never heard CD sound so good.

On phono it's probably just a bit better than the NAIM.

It has a grip on the SARAS beyond the 135s.........never thought I'd say that.

It's staying.

I hope it doesn't go bang as Jez implies parts are unobtainable!
Click to expand...

Oh goodness, I need to go for a lie down :eek:




Just don't go googling 'JVC A-X9"........just don't :0
 
Robert said:
Oh goodness, I need to go for a lie down :eek:




Just don't go googling 'JVC A-X9"........just don't :0
Click to expand...

AX9 is stunning but I looked at the design and IMHO the 1010 is better. The power caps, for instance, are superb things. Someone really designed this with SQ in mind.
 
Never seen or heard a 1010, but certainly JVC amplifiers are sleepers.
Some bargains out there for sure.

Visually I like the A-X55/77 series best which are essentially the previous series repackaged.

I'm still amazed the SARAs aren't tripping the protection - that's another wives tale we can put to bed. Then again the AX4 drives ESLs without problem also.
 
It runs hot but then the fans on the 135s used to come on as well.

It's the DAC in that's staggering, I'm hearing subtleties and detail I've never heard before.

Phono ain't too shabby either, just listen to my personal ref track and it's better than I have heard it before, not a huge difference but something you can hear; it seems calmer and more considered but still dynamic!



I need to get the user manual and a remote control for it.
 
Robert said:
Not much in that circuit that couldn't be satisfactorily substituted with modern parts though, should they fail which is very unlikely for the line and EQ sections.
The power amp uses nothing that can't be fixed with good comparable off the shelf parts today.

There's a thread somewhere on AK where the phono IC in the AX-1 had failed and it was possible to adapt the board easily to take a modern dual op amp, with better performance.

You'd have a dead A-X series running in no time in your workshop!
Click to expand...

What I was more specifically referring to is the low noise dual jfets in the phono stage. I should maybe have been clearer in that I was referring to Jap amps in general rather than the JVC specifically.

Yes I could easily replace the op-amps...

Toshiba, Hitachi, NEC and ROHM made things like low noise dual fets and transistors (also single ones) which are still the best ever to have existed and were made mainly for phono stages (as well as other uses). Now that the major Japanese companies are no longer involved in vinyl reply they have stopped making them.... Hence the likes of 2SK170's being so sought after when a NOS stash is found anywhere. Linear Integrated Systems in the USA are now re-manufacturing a few of the most sought after devices from Toshiba, which is great, but apparently they cannot quite match the quality of the original Toshiba parts from 30 years ago!

Another issue from a commercial POV is that when unobtainium parts need replacing it can take hours to find a suitable replacement part, or to work out how to modify something to do the job, and as long again to find a stockist who can supply them and isn't quoting min orders of 1000+. Time is money!
 
Arkless Repairs said:
What I was more specifically referring to is the low noise dual jfets in the phono stage. I should maybe have been clearer in that I was referring to Jap amps in general rather than the JVC specifically.

Yes I could easily replace the op-amps...

Toshiba, Hitachi, NEC and ROHM made things like low noise dual fets and transistors (also single ones) which are still the best ever to have existed and were made mainly for phono stages (as well as other uses). Now that the major Japanese companies are no longer involved in vinyl reply they have stopped making them.... Hence the likes of 2SK170's being so sought after when a NOS stash is found anywhere. Linear Integrated Systems in the USA are now re-manufacturing a few of the most sought after devices from Toshiba, which is great, but apparently they cannot quite match the quality of the original Toshiba parts from 30 years ago!

Another issue from a commercial POV is that when unobtainium parts need replacing it can take hours to find a suitable replacement part, or to work out how to modify something to do the job, and as long again to find a stockist who can supply them and isn't quoting min orders of 1000+. Time is money!
Click to expand...

According to the JVC blurb the jfets on the phono input were developed specifically for a high end phono amp, and the technology trickled down into the standard range. It's certainly very quiet. Not very likely for those to fail though.

Other things are more tricky, such as the RETs on the output of the Pioneer NSA amps. Need to look after those!

The real problems come with bespoke IC modules. Technics were a big fan of those.
 
Robert said:
According to the JVC blurb the jfets on the phono input were developed specifically for a high end phono amp, and the technology trickled down into the standard range. It's certainly very quiet. Not very likely for those to fail though.

Other things are more tricky, such as the RETs on the output of the Pioneer NSA amps. Need to look after those!

The real problems come with bespoke IC modules. Technics were a big fan of those.
Click to expand...

It would probably be possible to find a suitable replacement for those RET's unless they were in a weird custom package.

Indeed Technics were fond of those.. and knew how to charge for replacements!
I once had a base model Technics amp in and the output module had gone. I was quoted around £85 for a new module and that was about 12 years ago! The amp was only worth maybe £45 if sold so that was another skip job.

Even the many ASICs such as the "Super A" ones in the JVC are potentially a huge problem. I've no idea of their availability but it would not be possible to use anything other than the exact replacement for this. I guess one of the big advantages of UK amps is the makers were far too small to have semiconductors made specially for them and so everything is pretty generic and still easy to replace...
 
If you want to see inside one of the those Super A devices, the A-X5 service manual gives the schematic. I think that model might a year older so used a discrete implementation, then they managed to integrate the circuit.
 
Well mine looks almost NOS, there is zero wear to any controls and no marks on the facia at all, zero! I'm a fussy bugger but this is a close to new as it's possible to get for something that has actually been used. Definitely used in a non smoking house.

If it goes bang then so be it but for the moment I'm in heaven....
 
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