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

[biph911]

Received mine yesterday. I've got 627s in the DAC and 1469s in the amp section. I'll report back once it's burned in.

Definitely going to increase the resistor size in the LED board. Those things are bright.

[Penchum]

Originally Posted by biph911

Received mine yesterday. I've got 627s in the DAC and 1469s in the amp section. I'll report back once it's burned in.

Definitely going to increase the resistor size in the LED board. Those things are bright.

Yep, they sure do get your attention!
Do you know a good source for 4.7kOhm 1% resistors for that, or will 5% work as well?
Thanks! ANYONE !!!!!!

[Penchum]

Originally Posted by strologu

Hi everybody,
i'm just brand new on head-fi, so let me say hello to everybody one more time!
I've started reading this long looong thread on the Zero DAC, and..mmmm...it seems so interesting!
I'm sure the DAC section is pretty nice, maybe not the last word in high-end converters, but it looks like a very nice unit.
The headphone amp section is what makes me wonder hot good it could be..there are someone who have tried the built.in amop of the Zero DAC with my cheap and beloved Sony mdr-7506?

Hi Strologu,

I'm not sure if anyone has driven a set of those Sony's before. But, I can give you some info on the headphone amp. It's a dual mono design, has Opamps in sockets, so you can customize it's sound, and it is quite powerful. Many current owners (me included) are driving 300ohm headphones with ease.

When I changed from MP4 player, amp, to my HD-650s; to lossless files from my computer, optical out to the Zero, and used the built-in headphone amp, I was shocked at how much better it really sounds! Now, I have my Little-Dot MKIVse tube amp hooked up the Zero's DAC output, and the sound is incredible.

Some nights, I like to listen to something other than my tube amps, and I just plug into the Zero's headphone amp. It really does sound great. The price sure is nice, according to the wife!

[strologu]

Hi Strologu,

Hi,
glad to to talk with you, and thank you for the info.

I'm not sure if anyone has driven a set of those Sony's before. But, I can give you some info on the headphone amp. It's a dual mono design, has Opamps in sockets, so you can customize it's sound, and it is quite powerful. Many current owners (me included) are driving 300ohm headphones with ease.

..mmm..it sounds good! It seems to be a nice design..

Now, I have my Little-Dot MKIVse tube amp hooked up the Zero's DAC output, and the sound is incredible.
Some nights, I like to listen to something other than my tube amps, and I just plug into the Zero's headphone amp. It really does sound great. The price sure is nice, according to the wife!

[/QUOTE]

So the built-in amp, for what you're writing, seems to sounds as good as the Little Dot MKIV..am I right? Is it also tube-like sounding?
Thanks in advance

[Penchum]

Originally Posted by strologu

Hi,
glad to to talk with you, and thank you for the info.



..mmm..it sounds good! It seems to be a nice design..

So the built-in amp, for what you're writing, seems to sounds as good as the Little Dot MKIV..am I right? Is it also tube-like sounding?
Thanks in advance [/QUOTE]

Ow, ok, to clarify my sloppiness The built in headphone amp is solid state. Different Opamps will "flavor" the sound, and you can go warmer, or brighter, those kinds of things. My MKIVse is hooked to the DAC outputs of the Zero (RCA's on the back). One click of the Phones/Pre-amp switch on the front of the Zero, and you re-direct the DACs output from "built-in headphone amp" to RCA outputs in the rear...to my MKIVse.

No, the built-in headphone amp isn't as good as my MKIVse tube amp. But, it is good in it's own wright. It is going to sound better than portables, and it is going to sound better than headphone out jacks in receivers and the like.

What makes the Zero a perfect upgrade "stepping stone" is the fact that you can get one, and listen to clean solid state from your digital sources, using your headphones, right away. Later on, after saving up some money, you can add a tube amp or solid state amp for a more ultimate experience. You'll have all the bases covered!
Does that make sense? If not, tell me please.

[strologu]

Hi Penchum,
thanks a lot, first of all

No, the built-in headphone amp isn't as good as my MKIVse tube amp. But, it is good in it's own wright. It is going to sound better than portables, and it is going to sound better than headphone out jacks in receivers and the like.

That's what i need to know, just to understand how high can fly the built-in amp. But now, i don't know if it could be better or not than my actual amp..
i normally listen to lossless files with my laptop and a Digidesign Mbox2 Mini as DAC/amp......

What makes the Zero a perfect upgrade "stepping stone" is the fact that you can get one, and listen to clean solid state from your digital sources, using your headphones, right away. Later on, after saving up some money, you can add a tube amp or solid state amp for a more ultimate experience. You'll have all the bases covered!
Does that make sense? If not, tell me please.

Oh yeah, it make sense! This DAC/amp seems the rightest thing on heart to start building a nice system without crying at the wallet

[Penchum]

Originally Posted by strologu

Hi Penchum,
thanks a lot, first of all



That's what i need to know, just to understand how high can fly the built-in amp. But now, i don't know if it could be better or not than my actual amp..
i normally listen to lossless files with my laptop and a Digidesign Mbox2 Mini as DAC/amp......



Oh yeah, it make sense! This DAC/amp seems the rightest thing on heart to start building a nice system without crying at the wallet

Well, I'm unfamiliar with the Mbox2 mini, so I can't really speak to that. Maybe one of the users here can chime in and tell us.?

[strologu]

Originally Posted by Penchum

Well, I'm unfamiliar with the Mbox2 mini, so I can't really speak to that. Maybe one of the users here can chime in and tell us.?

Would it be nice if someone could tell something about it (argh! hope i'm writing correctly..my english is terribly rusty)
Anyway, if i would try the Zero, which opamp do you recommend to have a warm sound? Maybe i could order the Zero with right opamp in..

[Penchum]

Originally Posted by strologu

Would it be nice if someone could tell something about it (argh! hope i'm writing correctly..my english is terribly rusty)
Anyway, if i would try the Zero, which opamp do you recommend to have a warm sound? Maybe i could order the Zero with right opamp in..

For a warmer sound, Lawrence (the seller on ebay most have used) can also sell you the OPA627s, (which are single Opamps, so you have to have two of them on an adapter) and he puts them in for you. He also gives you the default Opamp, even though you upgraded. The OPA627s are warmer and richer than any of the other Opamps we have tried so far. Very recommended. Ow, and your english is just fine.

[strologu]

The OPA627s are warmer and richer than any of the other Opamps we have tried so far. Very recommended.

Thanks for the suggestion The OPA267's should be mounted on the amp section, right?

Ow, and your english is just fine.

I did'nt expected
I'll be on-line tomorrow..it's time to sleep in my side of the planet (00:35 AM at the moment)
Thanks in advice

[kmel]

Originally Posted by Penchum

Do you know a good source for 4.7kOhm 1% resistors for that, or will 5% work as well?

Everything works fine: 4.7kOhm up to 10kOhm, 1% up to 10%, but 500mW should be fixed.

Source... Radio Shack? It's less than 0.01$, perhaps you have to buy 10.
Or go to an electronics store near by a technical university.

You can look at digikey.com and newark.com, which is the US version of Farnell.

Found more heatsinks: Heat Sinks for DIP

[Penchum]

Originally Posted by strologu

Thanks for the suggestion The OPA267's should be mounted on the amp section, right?

I did'nt expected
I'll be on-line tomorrow..it's time to sleep in my side of the planet (00:35 AM at the moment)
Thanks in advice

Actually, the OPA627's would go into the DAC section. The DAC does influence the overall sound of the Headphone amp section. Good night!

[aural1ty]

Originally Posted by Henmyr

Great. I have the LT1469IN8 so it should probably work even better then. Will probably put it back in the dac.

Please do! I really enjoyed reading about your earlier opamp tests so I've been looking forward to your impressions of using the LT1469 in the DAC! I remember you wrote it was maybe the next one in line for trying.. Well, the LT1469 seems pretty hot for DAC duty so I say let it do it's thing!

I'm still new to opamps so starting to get the hang of it but please correct me if I'm wrong, anyway I was thinking about high temps:

The AMP board takes 2 dual chips for a total of 4 opamps. Assuming it only uses one opamp for each sound channel, then only 1/2 in the left chip and 1/2 in the right chip are used.

The DAC board takes 1 dual chip for a total of 2 opamps. Assuming it uses both opamps for both sound channels, then both opamps in the chip are used.

So I think a dual opamp chip should then consume twice as much power when inserted in the DAC socket, compared to an AMP socket, meaning twice the heat dissipation.

Somewhere back in the thread is was mentioned that high temp could be a sign of oscillating which I guess is true, but I don't think that's the case with the Zero and these opamps, they seem to work perfectly and I think it's just the huge power consumption difference. Looking at these numbers I understand the other seemed really hot after using the LT1057:

Supply Current Per Amplifier:

LT1057: 1.7mA typ - 2.8mA max
LT1361: 4.0mA typ - 5.0mA max
LT1469: 4.1mA typ - 5.2mA max
LT1364: 6.3mA typ - 7.5mA max

The LT1057 should come out coolest, LT1361 and LT1469 much warmer and LT1364 the hottest of these, and if my theory is correct, each of them run warmer in the DAC socket than in the AMP sockets.

Anyway, these LT chips seem capable of operating at very high temperatures, like Penchum posted they're apparently good for up to 150'C internally so should be no worries. I guess it's easy enough to put a VGA RAM sink on it or something but as long as it's within spec that's pretty useless. Temperature should not affect performance unless it goes out of spec (at which case you may be more concerned with permanent damage). Say the case would be 10'C warmer than the room temp, no let's say 20'C warmer. On top of that have a room temp of 35'C now that would be 55'C air temp inside! Even this 55'C condition would still not push it, it's well within the specified operating range from -40'C to 85'C. Think it's pretty safe to say there's Zero chance of overheating in this case

[Penchum]

I'm not exactly sure how it is routed in the headphone amp, since it is a dual mono design. However, I'm still under the impression that the heat is not only within normal limits, but has nothing to do with oscillations or instabilities. I think a small chip cooler stuck on there, and we'll never give it another thought.

When we tried the AD797's on an adapter in the DAC, it was most definitely heating up due to some high frequency problems! It sounded like psychedelic liquid highs on acid and downers! Those little b_stards got hot quick too! That was the only time I was worried about trashing my Zero.

[Penchum]

Originally Posted by kmel

Everything works fine: 4.7kOhm up to 10kOhm, 1% up to 10%, but 500mW should be fixed.

Source... Radio Shack? It's less than 0.01$, perhaps you have to buy 10.
Or go to an electronics store near by a technical university.

You can look at digikey.com and newark.com, which is the US version of Farnell.

Found more heatsinks: Heat Sinks for DIP

Thanks Kmel,
The last place my mind goes thinking about electronics is Radio Shack, but you are right. They will have them and cheap too.