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

[kmel]

Originally Posted by aural1ty

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

IMO the supply current is used even the opamp isn't amplify anything. I don't think that is the only cause of the high temperature.

I found following statement on physicsforums:

The only thing that will make an opamp hot is if its output current spec is exceeded, which you're not going to do when you pin the output open circuit one way or the other.

Let's take a look at the current output:

OPA2604: 35mA typ (standard Zero type)
LT1057: ???
LT1361: 34mA typ
LT1364: 60mA typ
LT1469: 22mA typ

If the Zero takes more than 22mA the LT1469 is running hot.

[Penchum]

Originally Posted by kmel

IMO the supply current is used even the opamp isn't amplify anything. I don't think that is the only cause of the high temperature.

I found following statement on physicsforums:


Let's take a look at the current output:

OPA2604: 35mA typ (standard Zero type)
LT1057: ???
LT1361: 34mA typ
LT1364: 60mA typ
LT1469: 22mA typ

If the Zero takes more than 22mA the LT1469 is running hot.

I'm following you here, but why would the LT1364 get even hotter? Or was the LT1469 hotter than the LT1364? Anyone?
Also, those are typical ratings. The maximum ratings require math beyond my capabilities and direct measurements from the Zero.
Anyone with a Zero, a good volt meter and math skills want to take a crack at it?

[edguetzow]

Originally Posted by kmel

IMO the supply current is used even the opamp isn't amplify anything. I don't think that is the only cause of the high temperature.

I found following statement on physicsforums:


Let's take a look at the current output:

OPA2604: 35mA typ (standard Zero type)
LT1057: ???
LT1361: 34mA typ
LT1364: 60mA typ
LT1469: 22mA typ

If the Zero takes more than 22mA the LT1469 is running hot.

I seem to recall that the 1364 ran very hot also. At 60mA it should not have begun heating up as compared to the stock OPA2604.

Seemed like it was just as hot as the 1469 but I am judging strictly by touch.

[Penchum]

Originally Posted by edguetzow

I seem to recall that the 1364 ran very hot also. At 60mA it should not have begun heating up as compared to the stock OPA2604.

Seemed like it was just as hot as the 1469 but I am judging strictly by touch.

I think you are right. I honestly hadn't given it much thought, beyond "that's hot". What is bothering me the most, is that I've been using one of my Zero's with the LT1364 in the DAC for a very long time now. I wonder if we should be worried or not.

[Penchum]

I've also been using the LT1364 in my MK1 portable, with outstanding results! I really believe it is out performing the majority of portable amps on the market! Go figure!

[Henmyr]

Originally Posted by aural1ty

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 hit the wall right after the LME49720 test, and only heard the imperfections in the op-amps, the small colorations. I have taken a small break to get back on enjoying the music again as well as the zero. I will do the LT1469 test soon I think however. Have ordered two OPA627AP also to use as dac.

I'm using LT1469 in the dac now with LME49720 in the amp, and it is a good combination, as was LME49720(dac) + LT1469(amp).

[strologu]

Hi Henmyr,
i've just seen that you're using this unit as amp too, with a Beyer DT-990, a headphone i know pretty well.
Can you tell me how does it sounds, compared to the Meyer dedicated amp?
Thanks in advance

[Henmyr]

Originally Posted by strologu

Hi Henmyr,
i've just seen that you're using this unit as amp too, with a Beyer DT-990, a headphone i know pretty well.
Can you tell me how does it sounds, compared to the Meyer dedicated amp?
Thanks in advance

They are very similar. At first, when the zero was new, it was very clear and sharp, much more clear than H5, but now after burn-in it's more mellow than before, and approching the H5 more and more.

With LME49720 (same as LM4562) (dac) + LT1469 (amp) the tonality is also very similar to H5, although the zero is just slightly very slightly more clear.

I have a hard time comparing the two (especially with dt990, as they have a very significant signature), but I would say that they are about equals.

The soundstage might be slightly larger than the H5, depends on what Op-amps are in.

The H5 has a very natural sound and good timber, something which the zero is just slightly slightly very slightly worse than H5 (this might be corrected with the right op-amp combination).

Overall, I have a very hard time to declare a winner during my short test.

There might be a very good op-amp combination for zero with dt990 which puts it significantly ahead, but I haven't found that for dt990 yet (and maybe never will, as I'm getting closer and closer to selling them).

This was tested with the DT990. With dt880 and ms2i, I think (must listen more) that I prefer the zero.

I hope that the zero will clear up with more burn-in, because I liked the clear sound it had in the beginning very much. I'm hoping OPA627 will bring some air also.

[mrarroyo]

Has anyone compared this Zero Dac w/ an Oritek modded Zhaolu? Thanks.

[strologu]

Hi Henmyr,

Overall, I have a very hard time to declare a winner during my short test.

thanks a lot for your answer. So also the built-in amp is a little-killer one

I'm hoping OPA627 will bring some air also.

I'm gonna buy a unit with OPA627 on DAC, but i'm really confused about which opamp for amp section, do you have any suggestion?
My phones are the Sony mdr-7506, that are a bit brilliant..
Thanks in advance

[pincellone]

Originally Posted by mrarroyo

Has anyone compared this Zero Dac w/ an Oritek modded Zhaolu? Thanks.

I wonder how many gullible people would be willing to pay additional $700 for such negligible mods compared to the original Zhaolu, it costs 7 times more

Get a life (and a Zero, of course...)

[Henmyr]

Originally Posted by strologu

Hi Henmyr,

thanks a lot for your answer. So also the built-in amp is a little-killer one

I'm gonna buy a unit with OPA627 on DAC, but i'm really confused about which opamp for amp section, do you have any suggestion?
My phones are the Sony mdr-7506, that are a bit brilliant..
Thanks in advance

The op-amps in the amp are very dependent on the op-amp in the dac, so I can't know at this moment which op-amp will be best with OPA627 in the dac. I find the LT1469 and LME49720 (same as LM4652) to be the best overall so far for the amp with dt880/ms2i/dt990.

EDIT: Do not neglect the stock op-amp combination, as I find it to very enjoyable with every headphone.

[Pete7]

Originally Posted by mrarroyo

Has anyone compared this Zero Dac w/ an Oritek modded Zhaolu? Thanks.

How about just an unmodded Zhaolu?

[Pete7]

Originally Posted by pincellone

I wonder how many gullible people would be willing to pay additional $700 for such negligible mods compared to the original Zhaolu, it costs 7 times more

Get a life (and a Zero, of course...)

Haven't been around very long,eh? The last time I checked Ori sent out a brand new modded unit for close to $450. Discrete output isn't what you'd call a "negligible" mod, like say swapping out an op-amp.

[strologu]

Hi Henmyr,

The op-amps in the amp are very dependent on the op-amp in the dac, so I can't know at this moment which op-amp will be best with OPA627 in the dac.

i've just e-mailed Lawrence to ask which one he recommend with the OPA627 in the dac..he suggest me another opa627 in the amp section..but i'm not sure i've understand well..another OPA627 in the amp?? Is it possible?

EDIT: Do not neglect the stock op-amp combination, as I find it to very enjoyable with every headphone.

It's another interesting point of view
Just one more question: when you tested the Meier h5 vs the Zero internal amp, did you used the stock op-amps?