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JVC AX-Z1010TN - Review (part II)

I thought it might have been you ;)

What preamp are you using with your M-3030 or do you run them direct ?
 
I haven't managed to find a decent matching P-3030, but I'm not too bothered tbh. I use a Nakamichi CA-5, which is a great pre, and a better visual match in an all black system. As a point of reference, I didn't pay much more than that ones current price, and mine is in much better visual condition ;)
 
Interestingly the dual tape inputs have come into their own.
The recent addition of a Sony TC K570 has required the use of Tape 1&2 and the feature is really good!
 
I also have these on my Z711 : I thought it might be the perfect way to fit a miniDSP unit into the loop, if ever desired...
 
I have just acquired the JCV AX-Z911 amplifier this week to replace my old naim amp, so I have been reading this thread with interest. It's very impressive, makes me want to play music loud as it has all the rhythm of naim but with more warmth and musicality. I'm loving it.

However, I have found a problem with it and wondered if anyone could offer some advice. When I play music through the digital inputs, both coaxial and optical, the amp cuts out around 10 o'clock on the volume control but seems fine at lower volumes. Other inputs are working nicely. The only criticism I had when I plugged it in was that it had a very thin power cable which was unexpected in an amp that uses a lot of power. Could the problem be power related? It does feel hotter when the DAC is working too which doesn't seem a problem on analogue inputs.
 
Have you checked that there is no bad speaker cabling/shorts.
The amp runs in psuedo class A on the digital inputs if you use the DAC direct button and it may be tripping out becuase there is a cable short or speakers issue.
It can do loads as low as 2 ohms so will produce lots of amps before it calls time!

Try turning off the speakers via the front buttons plug in some headphones and slowly turn the volume up.
If it stays on then there is a problem with the cabling or speakers as the headphone output is actually fed from the main power amp.

P.S. The mains cable is more than enough, don't sweat it.

P.P.S. congrats on the purchase!
 
Thanks very much for the advice. I gave it a try this morning but it was still cutting out without the speakers attached when I select the digital input selector and played music at high volumes. At least I know the speakers are wired up fine.

However, you made an interesting point about the DAC Direct Button as I had not tried it up to this point. It does not cut out when I select the DAC Direct Button and play music loud through it. Appears to sound a little different too and does not need so much volume. Am I imagining this? I need to learn more about this amp. It has hidden qualities. I'll try and get hold of a manual and learn how to use it.
 
The DAC direct cuts out the tape loops, balance control and most of the preamp section.
Have you got a tape connected?
If you look into the amp on the right hand side there are two green LEDs (on the 1010 there are) that glow as it's nearing it's input limit.
As you turn up the volume do they start to glow?

You comment about volume differenc between DAC direct on/off suggests that there is a problem with something ion the preamp section as it should be the same.
The amp runs very hot in DAC direct/digital but I don't notice any volume differcne just a cleaning up of the sound.
 
No tape player, just CD and phono at the moment.

You have just pointed out something else I had not noticed. The led display is missing the glow of the "Digital Pure A " LED and the surrounding LED display. Volume different is slight but it sounds like a problem that needs professional attention and a service. It was a filthy mess when I bought it but I'd be loathed to take it back to the seller because its sounds so fantastic. It may just need a better clean than I had the courage to do.
 
flatpopely said:
The amp runs very hot in DAC direct/digital but I don't notice any volume difference just a cleaning up of the sound.
Click to expand...

My Z711 doesn't run hot in either DAC or CD Direct mode - it is the most effortless amp I've ever run (well, apart from the Z101TN, which without a blind test seems identical - both a clear step up from the smaller models though).

Simon - I see you're in Berkshire & toprepairman on this forum used to work for JVC and is familiar with many of their older amps. I've never got beyond talking to him on the phone, but he seemed both knowledgeable, helpful & friendly. He's near Leatherhead in Surrey somewhere.

Btw, my 711 arrived from Germany with the LEDs not burning, so I had my local repair guy here in NL replace the bulbs - simple & inexpensive.
 
If the Z711 doesn't run hot then it's not using the Dynamic Super-A that the 1010 does. It should run hot, its Class A.

EDIT, I see it does. I suspect the bias is set incorrectly.
On normal inputs it runs warm on digital it's hot.
 
My Z1010 runs quite hot in 'Digital direct' but only after hours of use, this feature is the main reason I'm hanging on to the amp, it really does sound very good. If you think your Z911 sounds fantastic with potential problems, think of how it could sound after a good service, I think it can be well worth it for the higher end Japanese equipment.

Also if anyones looking for visually matching JVC speakers, the S-M3 and S-M5 are almost the same colour as the 'TN' line, and sound good for small speakers, there's some pics in my Luxkit thread in the DIY section ;)
 
flatpopely said:
If the Z711 doesn't run hot then it's not using the Dynamic Super-A that the 1010 does. It should run hot, its Class A.

EDIT, I see it does. I suspect the bias is set incorrectly.
On normal inputs it runs warm on digital it's hot.
Click to expand...

I thought “Dynamic Super-A” really meant “Class A like sound from a Class AB circuit”!?

None of mine have run what I’d call hot (= you wouldn’t want to rest your hand on the case at the hot spot) & i’ve owned 5 of them (3 x Z1010TN, R337 & Z711). I’m keeping the Z711 as to me it’s the best looking & my old ears reckon the sound is excellent.

Edit : although with more demanding speakers, the Z1010TN must be the sensible choice - it’s extra weight presumably means it has more substantial power supplies.
 
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I think even quality amps like these will inevitably have problems when you pick them up, just because they are old and probably stored poorly. Its got to be worth investing a little to restore them to their former glory. The heat generated when running the DAC is a little concerning for me so I'll get someone to service it. I know a man in Basingstoke who fixed my last JVC amp but toprepairman must be worth a try too.

Hempknight said:
Also if anyones looking for visually matching JVC speakers, the S-M3 and S-M5 are almost the same colour as the 'TN' line, and sound good for small speakers,
Click to expand...
My grandfather had a pair of S-M3s that were sadly lost when he died. They were good from memory. I could use a pair of those in the kitchen.
 
Toprepairman serviced my JVC 1010 amp when it arrived from the Netherlands with a bent shaft on the volume knob due to dodgy packing. He also changed the transformer setting from 220V to 240V. I'd definitely recomend him.

Mine doesn't run hot using the direct DAC input, and that's with other components sat on top of it.
 
Just had my AX4 serviced by Toprepairman. What a star he is. It was down in level on one channel and sounding a bit iffy on the other. I took it thinking it would be a costly job, but probably worth it. Turns out it just needed a service - contacts cleaned etc, etc. He just charged me for an hour of labour and it's now in the main system sounding fabulous.

I may one day get a 1010 but as I'm completely satisfied with the DAC I have, I'm not sure I want to go to the expense. All for under £100!
 
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