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Review: ZERO 24 BIT/192KHz DAC/Headphone Amp/Pre-Amp - Page 619

post #9271 of 9361
Quote:
Originally Posted by AmarokCZ View Post

It was just a wild guess...

From what I can tell it seems that head-amp is OK, and reciever is also OK. Problem could be DAC itself or buffer/filter behind DAC.

Yes. It seems ok for me too. It sounds like digital noise, the pop sounds..

 

I see pepole who modify their Zero, they mount bigger heat exchangers on the black 3 legs "things" in the dac :D

 

Amarok Example:

 

 

 

Should i do it? :)

post #9272 of 9361

Try checking temperature of heatsinks with your hand, of you can withstand the temperature it's OK. The most hottest should be 2 heatsinks near socket with dual BB627 in it.

post #9273 of 9361

Okey. Thank you :)

 

I will check it out. If they are too hot, is it possible that they make/generate pop sounds?

Quote:
Originally Posted by AmarokCZ View Post

Try checking temperature of heatsinks with your hand, of you can withstand the temperature it's OK. The most hottest should be 2 heatsinks near socket with dual BB627 in it.

post #9274 of 9361
Quote:
Originally Posted by tbend View Post

Okey. Thank you :)

 

I will check it out. If they are too hot, is it possible that they make/generate pop sounds?

I have tested the dac further. The heatsinks is not very hot, no problem to touch every component in the dac while it's in use.

The BB627 is also getting a little warm, but no problem to touch it either.

 

 

Have checked the underside of the mainboard for solder points, but eveything looks ok.

 

Dont know what to do :-(

 

The popsounds is coming when the music og sound is nearly quiet, when its just ambient sounds its worst.

And its exactly the same from optical, coax and usb. 

post #9275 of 9361

anyone found this single to dual opamp converter to be worked on Zero dac?I saw one on ebay listing to be much cheaper than dual to mono adapter.I rather going to buy this one since they are much cheaper than dual to mono adapter which is around $40.

 

http://www.ebay.ca/itm/2-X-GENUINE-BURR-BROWN-OPA627-SINGLE-DUAL-OPAMP-CONVERTER-/251157632021#ht_1758wt_1163

post #9276 of 9361

Hi Everybody,

 

 

I've got a Grado SR125, I use them with my ESI Julia sound card and I want to get a better sound quality by connecting a DAC (for example ZERO 24 BIT) to the Julia sound card. I read the post above about the problems with the hiss. I just wonder if is it possible to fix by using an external amp for instance a clone of Grado RA-1 ?  http://www.ebay.com/itm/18V-Cmoy-Ra1-JRC4556-Headphone-Amplifier-Amp-RECHARGEABLE-PP-Compatible-W-Grado-/170952843574?pt=LH_DefaultDomain_0&hash=item27cd956136     

 

Thanks!


Edited by sleek2000 - 12/7/12 at 2:28am
post #9277 of 9361

Hi. Does someone have Schematics for the Zero Dac ? (With USB)

 

tor_steve@hotmail.com

 

Thnx :-)

post #9278 of 9361

sleek2000: if everything is OK (=nothing is defective/damaged) than the hiss is only problem of headphone amplifier and only with sensitive headphones (IEMs, Grados,...). You can either use external headphone amplifier or change the old AMP for a new one (for example see my signature).

tbend: do you need whole or partial schematic?

post #9279 of 9361

HI. 

 

I neeed scematics for the mainboard, do not need schematics for the headphoneamp :-)

Quote:

Originally Posted by AmarokCZ View Post

tbend: do you need whole or partial schematic?

post #9280 of 9361

I've been using my zero amp for several years now, both with my hd595 headphones and my cambridge audio 640a v2 to my vifa premium 11 speakers.

I have read some good things about the amp in the 640a v2, and I was wondering whether anyone knows which one would be better, the zero headphone amp or the 640a v2 amp?

post #9281 of 9361

The zero sounds really interesting. Was reading the first ~100pages and some things made me curious so I searched the thread, but seems nobody have a answer what the actual output impedance is of the headphone output. Sure its only important for cans below 100ohm, but for me its some crucial thing to know because I need a amp for mixing/mastering and need to be sure the amp matches my cans (50ohms). Someone knows the actual output impedance?

 

What would be the best opamp combi for a uncolored und neutral playback scenario?

post #9282 of 9361

I' not surprised you didn't find it, because there isn't really much in this thread (considering the 619 pages).

 

Output impedance of headphone amp (including impedance of connector) is very low: ~0.5ohm (there is 0.3ohm resistor in series).

 

There isn't any combination of opamps which makes it neutral, because DAC is a bit veiled and headphone amp is quite midrangy.

You can "save" DAC with some bright OA (AD797 could be suitable).

post #9283 of 9361

Ok, seems not like a good solution for me then. But regarding the impedance. When its that low, why so many here got problems with low impedance headphones? I'm curious. What did you mean with I could save the dac with some OA. The Opamps ?

post #9284 of 9361

Problem with low-Z headphones is because headphone amp has too much gain and it's hard (more like impossible) to set volume that's not too loud but still with good channel balance. Second problem could be caused by head-amp noise, but it's problem only with very sensitive headphones (most IEMs).

The DAC is little dark, so you could save it with brighter operational amplifier.

post #9285 of 9361

I think the headphone amp section in this is worth the money in itself, One criticism is the DAC output has a very unclean noise profile (like sizzling eggs) this is very low in level and virtually inaudible at normal listening levels but I would prefer if it was not there. You can only hear it if the you amp/speakers are cranked. The other issue is the case is not earthed which is pretty bad from a safety perspective IMO. I earthed mine myself as the first job out of the box. There is no excuse for this whatsoever and the manufacturer must not do it because of money saving. I recommend anyne buying one check the earthing arrangement and if you cannot do it yourself get an electrician to do it, it is probably a 20 min job for a sparky.

 

The headphone output quality is divine.

 

I am not aware of anything that is this great at this price.

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