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

[Garret Jax]

Originally Posted by Ben Diss

I'm a little lost on this whole HDAM thing. I apologize if this was covered somewhere in the last 800 pages of this thread.

- What does HDAM stand for?
- How does the Earth or Moon compare to the OPA627?
- Where does one buy and how does one install LT1364's?

I bought a Zero from "wz" that has the OPA627's and I'm loving it. If I can further improve the sound, I may just do that. I'm thinking about doing the Franken caps upgrade as well.

Thanks.

I second this.

I have a Zero with OPA627's and LT1364's - this was the 'Head-Fi Special' from Laurence. Does the HDAM Moon replace these? I mean, OPA627 is an OPAMP, as is HDAM Moon, correct? Sorry, I am teh confused.

[ScottieB]

Not exactly sure about what HDAM stands for (something discrete audio module I think). It takes the place of an opamp, and is basically a more advanced, designed-for-audio version of a opamp. While opamps may not necessarily be designed for audio applications, the HDAM units use components designed to make audio sound good. They can replace any of the opamps in the Zero, although most here (me included) seem to replace the DAC with an HDAM - others have used 3 HDAMs though. I use an external amp so putting HDAMs in the Zero's headamp would be a waste.

So, yes, an HDAM would replace any or all of those opamps from your "head-Fi special" Zero.

Most have noted (myself included) that the HDAMs are more dynamic and detailed than the opamps. They just bring the music more to life. It was instantly noticeable and well worth the price to me as an upgrade.

The best place to get them is Audio-GD - many sig's here have the link - I don't know it off-hand.

Hope this helps.

[sandchak]

Hi folks,
I received the zero boards (both DAC and HP with connectors and all the opamps) from wsz0304 today.
I must say, this seller is just great, he shipped me the entire circuit board including the HP section which was fine, through DHL gratis !
I just fixed the boards and it works flawless..
I just have one question, if you guys can help me out:

1) I have hooked up the zeros through the spdif out of my onboard soundcard, when I am playing with zero preamp on (green light on - headphones not connected) in this case the volume can be adjusted by the zero - the left channel seems far weaker than the right channel.

BUT, when I am switching off the preamp (green light off and headphones not connected or even when connected) in this case the volume on Zero has no effect and I have to use the volume control (wave) on the computer - Both channels work fine..

Is this normal??..

Secondly, after every song ends or begins (through Winamp), there is a pop noise on the speakers..

Any help will be very much appreciated..

[DaMnEd]

Pops are a recurring problem with onboard soundcards, I'd suggest you use something better if possible.

[sandchak]

Originally Posted by DaMnEd

Pops are a recurring problem with onboard soundcards, I'd suggest you use something better if possible.

Thanks a lot. at least I have one of my queries sorted..

[ScottieB]

Originally Posted by sandchak

Hi folks,
I received the zero boards (both DAC and HP with connectors and all the opamps) from wsz0304 today.
I must say, this seller is just great, he shipped me the entire circuit board including the HP section which was fine, through DHL gratis !
I just fixed the boards and it works flawless..
I just have one question, if you guys can help me out:

1) I have hooked up the zeros through the spdif out of my onboard soundcard, when I am playing with zero preamp on (green light on - headphones not connected) in this case the volume can be adjusted by the zero - the left channel seems far weaker than the right channel.

BUT, when I am switching off the preamp (green light off and headphones not connected or even when connected) in this case the volume on Zero has no effect and I have to use the volume control (wave) on the computer - Both channels work fine..

Is this normal??..

Secondly, after every song ends or begins (through Winamp), there is a pop noise on the speakers..

Any help will be very much appreciated..

What are you listening through? Headphones on the Zero headamp? When the preamp button is NOT lit, the Zero's volume should do nothing. It is assuming you are conencting to another amp or speakers and gives a "clean" signal that does NOT pass thru the Zero's head-amp. When the button IS lit, you ARE sending the signal thru the Zero's headamp and as such the volume knob DOES affect the sound level. Whether you use headphones or not, this is still the same - even if only going thru RCA out. The relative strength of the two channels is likely due to your volume pot - the stock pot is known for having imbalance issues especially at low volumes (this would be avoided, of course, if the preamp is NOT lit, as you are bypassing the amp section in this case).

The popping is probably just a function of how your soundcard works - ie it stops sending a SPDIF signal to the DAC and then starts a new one for the new song. I suppose it could also be the music program and how it interacts with the sound card. What music app are you using?

[les_garten]

Hello,
To those that have questions about Low impedence. I just got some Denon Ah-D5000's today. They are 25 ohm and are working fine with the Zero. I am letting them burn in presently. I heard no "real" hiss issues. If I Crank the Vol pot on my LD MK V to 3 to 5:00 position or the Zero to the same position, I heard some "Transister Rush". But if music was playing, that woldn't be my biggest issue for sure. The Zero and the MK V handles the Denon's fine.

[sandchak]

Originally Posted by ScottieB

What are you listening through? Headphones on the Zero headamp? When the preamp button is NOT lit, the Zero's volume should do nothing. It is assuming you are conencting to another amp or speakers and gives a "clean" signal that does NOT pass thru the Zero's head-amp. When the button IS lit, you ARE sending the signal thru the Zero's headamp and as such the volume knob DOES affect the sound level.

The popping is probably just a function of how your soundcard works - ie it stops sending a SPDIF signal to the DAC and then starts a new one for the new song. I suppose it could also be the music program and how it interacts with the sound card. What music app are you using?

Hi Scottie,

thanks for chipping in..

1) I am listening through my multimedia Audioengine A2 speakers and not through headphones, as I plan to use the Zero only with my PC through speakers. For dedicated heaphone listening, I use the PH100 with my Nads.
What happens, like I mentioned in my earlier post is that when I am keeping the preamp section on with the green light lit, the left speaker is very weak(nearly 80%less) than the right speaker, in this case I can adjust the volume through the Zero.
This does not happen when I switch off the preamp - green light off - both speakers work as they should - In this case, the Zero Volume does not work and I have to make the changes on the computer mixer to set the volume.

2) as far as the music application, I am listening through Winamp..

Thanks again..

[ScottieB]

Well that means things are working as the should, you just have a balance issue somewhere in your head-amp. Most likely it is in the volume pot, as many others have noted this as well, but it could be anything I suppose. Do you have the same issue if you use headphones through the Zero?

[sandchak]

Originally Posted by ScottieB

Well that means things are working as the should, you just have a balance issue somewhere in your head-amp. Most likely it is in the volume pot, as many others have noted this as well, but it could be anything I suppose. Do you have the same issue if you use headphones through the Zero?

Just plugged in my headphones and it runs fine, no issues as such.. think its just one of those issues you mentioned..
In any case, everything works fine otherwise - well, nice to have the zero up and running after a month !!
Thanks Scottie + Thanks ALL ..

[x_lk]

Originally Posted by sandchak

2) as far as the music application, I am listening through Winamp..

Although I don't use it any more, if my memory still serves me, Winamp is able to do gapless playback with several configuration tweakings. The gapless playback can be achieved by killing the silence between tracks. There are different areas need to be tweaked, for playback of different encoding types, namely CD, WMA, MP3, OGG, etc. One of the strong point of foobar2000 is that it does gapless playback whenever it's possible, out of box. Try googling 'winamp gapless playback', if you don't want to switch.

[Currawong]

I need to put this back in my sig:

Introduction to the Zero DAC and Headphone amplifier. - Head-Fi: Covering Headphones, Earphones and Portable Audio

[K3cT]

Is the effect of replacing the op-amp with HDAM in the amp section of the Zero as profound as compared to the DAC?

How would the Moon HDAM do if I use it in the amp section?

[Ben Diss]

Originally Posted by Currawong

I need to put this back in my sig:

Introduction to the Zero DAC and Headphone amplifier. - Head-Fi: Covering Headphones, Earphones and Portable Audio

Yes, that's a BIG help. Thanks!

What about upgrading the headphone opamp? Any guidance on how that's done and where to source parts?

[arfett]

I love me some detail in my music, but I'm a bass-whore at heart. If I'm using an OPA627AU or Moon HDAM which I'm purchasing soon, what would be the best chips for the headamp to pump the bass? I've read that the LM4562 chips are bassy and I've got some shipping to my house right now, but are there any others for better thumping bass?