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

[Penchum]

Originally Posted by Normality

How else should I put it?



I have changed CD, and listening to Tom Waits, Bone Machine, I clearly realized that the overall balance is different from that of my CD player. The treble is lower in level, although it's much more 'detached' from the speakers' tweeters which is a good sign. Overall at present it's a bit too much a laidback sound for my taste; indeed the LT1364 and AD826 should do a lot of good to the sound. As it is now, I would want no OPA627.

This is also the way I recall my Northstar Design Model 192 sounding when I used a cheapish (but still better looking than this one) optical cable. Things had changed entirely when I switched to a coaxial cable. So I'm not in the least concerned about this.

It sounds like you are exactly on course. At about the 50 hour or so mark, the treble will become more pronounced and that laid back will lighten up some. More definition in the bass too.

[Penchum]

Originally Posted by Normality

Well things must be improving indeed, since I've just been listening to the same CD by Tom Waits (at higher volume than before 'cause my parents were taking a rest) & I already think I couldn't live anymore without the Zero.


It has really shed a new light on this CD (Bone Machine) which I knew so well... enough to show how great this album is (sorry can't put it into words ).


Something impressive about the sound (as opposed to the music) is the bass & the low level resolution (and the resulting ambience feeling) brought about by the Zero; coupled with the liquidity of the sound.

Yep, you are right on schedule. More jaw droppin' coming soon!

[jamato8]

Looks good. So what other dacs has the Zero now been compared to? At the price of admission though one really can't complain, from what I am reading, and this could be a very nice addition to high value dac or I should say it appears it already is.

[Penchum]

Originally Posted by jamato8

Looks good. So what other dacs has the Zero now been compared to? At the price of admission though one really can't complain, from what I am reading, and this could be a very nice addition to high value dac or I should say it appears it already is.

If I had doubts in the beginning, they are gone now for sure. Low cost flexibility is it's true strength. A new user with a notebook can buy the Zero and the headphones they always wanted now, get full use and enjoyment out of them until they have saved enough to pickup a separate tube or solid state headphone amp, to be driven by their Zero. We have MANY students doing this exact upgrade path, because they see the logic of it, as well as the thriftiness of it. Everyone deserves to have a Zero!

[Penchum]

Originally Posted by jamato8

Looks good. So what other dacs has the Zero now been compared to? At the price of admission though one really can't complain, from what I am reading, and this could be a very nice addition to high value dac or I should say it appears it already is.

On a more personal note, I have been totally blown away by the Zero. The level of quality it possesses, the build quality, its simple but eloquent design, ease of use and compact size all put together make it a "High Quality, High Value DAC/Head Amp". Even with all the amps I have now, I still plug my HD-650s into the Zero and listen to it's excellent sound quite often.

[AudioNoob]

Does anyone have both ld2 or ld mark II along zero, it would help to see a comparison.

[dsmudger]

Originally Posted by Penchum

I would really like to hear your (or anyones) impression of the DY2000. I have been so tempted to order it, but I couldn't decide between the normal or metal version, and before I spend on that, I wanted to know something! I guess my "envisioned" use would be in the DAC, for my digital to Vintage Zero. Thoughts?

I've tried the ceramic one in the DAC section - didn't spend too long with it but every time I've swapped it in with something or other in the headphone section I seem to remember thinking it was smooth but not detailed enough.. I'll try it again in a bit and report back if you like (I mean to order a few more opamps to try at some point soon so I'd better keep hold of it for a little while, but if you're in no hurry maybe we can do a swap for one you're not using - or if they're worth about the same as a pint of beer you can have it for free when I settle down a bit with all the swapping and changing )

Since my last post I've had a metal LME49720 in the DAC and the same in plastic DIP in the headamp (someone was asking about it a few pages back?) and it's the best sound so far (haven't changed for anything else in a few days anyway ) - it has its issues, like there's a definite notch somewhere in the high/mids - somewhere around where the vocals are in the theme tune to CSI:NY - last time I noticed it (optical -> TV), but overall it's the fastest, most detailed combination I have and although there's very clear treble, it's not fatiguing to listen to. Bass is not all that powerful, but what's there's quite fast/tight.

On my list to try next, from googling/reading around the place:
AD746
AD826 (dual)
AD827 (dual)
OPA627
OPA637
AD8066 (dual, but SMD only - will be lucky to find anyone selling pre-soldered ones on adaptors..)

Maybes:
AD825
AD828
AD8620
AD744 (single version of AD746 - likely to be much difference?)
OPA134

btw Normality mentioned back there not to use the AD826 in the headamp board? Why's that and is there something to look for on the spec sheet to know in future?

Some of those are pretty pricey so that'll mean I'll be putting those in the DAC anyway (better chip higher in the signal path seems to make sense..), but where possible I was thinking of repeating what I've got now with the LME49720 - all three the same in DAC/headamp to get an idea of the unit's characteristics and then try different combinations/try to match them up?

Or is it not that simple because they perform under different conditions/different configuration in each side (e.g one good for the DAC might be terrible in the headamp)?

[dsmudger]

Originally Posted by Normality

Also,

I have just ordered from National two LME49710 and two LME49720, all in the TO99 "metal can" package.

I have sockets to solder the duals to, and twin-DIP Browndog adapters to solder the singles on. Looks promising

Probably a good idea.. I just looked at the pinout on the datasheet and sort of shoved it in the socket (later twisted the top a bit to make a better connection when it didn't sound so good straight off - seems to work well enough from what I can tell..?)

[charley phogg]

Wow, you guys are ROCKIN'!!!! It's been a few rough days for me so I haven't been able to catch up on this thread. So much information you all are spitting out I think I'm going to have to create a separate folder and save certain pages for reference points...... hmmmmm wonder how long before that would baffle me? Thanks again to all the vaulable info you all or provding ofru us.

Fault, I guess I must of caught them between production runs, haven't heard anyting back on ship date so I guess I'll drop an email and find out status. I'm going bonkers checking my email every day.


Regarding the sound out of your Mac... there;s so many factors that come into play and I don't know a thing about Mac's, but I have heard they have good audio (?) I think.
If you're using onboard audio it won't be as good as a dedicated sound card because the cpu is having to do all sorts of things while it is coverting the audio , and also more possibility of noise being injected. But them again newer computers the audio has taken a big step in quality in the past year or wo.

Also I believe you have a laptop, which again I have no experience with, but everything in a laptop is a compromise, not to mention everything is jam packed inside the case.

All I can do is relate my experience with my pc's to give you and idea hopefully. My main rig I built myslef Intel Core2Duo and is 1 1/2 years old,and have a good, high quality and effiecent power supply in it that is roughly a foot above my sound card. I aslo have a failry decent video card which runs on a completey diffrent bus and chip then my soundcard, which Im sure also helps. And my sound cards is a Auzentech Xplosion with rolled opamps in it ( I forget which ones). My 5.1 speaker syatem is logitech 5300's, I think , I got such a good deal on them couldn't pass them up for games and movies. It has a controller that has the headphone jack in it. And right now I use a TotalBitHead out of usb.

When I plug my cans directly into the controller it sounds almost as good as my BitHead. I say alsmot becasue the sound is very similiar, just more refined, and less edgy with the BitHeadout of usb.

My other pc is an ancient run of the mill typical office pc with a intel p3 I think, probably 8 years old or so with crappy onboard audio. It will drive my 580's but sounds thin and tinny. With my Bithead in the usb it probably sounds as good as my main rig. But that is bare bones and I use asio4all on that one.

Sorry I can't be no more help then that, but at least you know there is hope. It could be some sort of conflict, or maybe just a matter of changing some settings or something.

Hopefully some others will be able to offer more help, or check out the copmuters section here for some ideas. My guess would be that you are being limitied from the onboard audio.

Good to hear of your pleasant experience with Graham. In my dealing with him through forums, he is very pleasant,passionate about his music and a genuinely nice and helpful man.

[AudioNoob]

anybody have the seller contact out of ebay?

[dsmudger]

Originally Posted by Normality

A few notes on some opamps mentioned:


AD746 (dual opamp) - only suitable for the amp; much too little output current for the DAC. Interesting for the amp, however.

AD827 (dual) - also little (but more at the threshold with acceptable) output current, otherwise great option for the DAC like the AD826. Not to be used in the amp due to very high Ib -> high DC offset which can blow you headphones!

OPA637 - not unity gain stable, thus not suited for the Zero at all.

AD8066 - not suited for the Zero at all since its maximum supply voltage is +/-12V like the AD8620, and the Zero has +/-15V throughout. And btw the AD8620 sounds better.

AD825 - single, good option for the amp mostly.

AD828 - specified as stable from G=+2, so I wouldn't try to use it in the Zero.

AD8620 - don't use it in the Zero, as above.

AD744 - single version of AD746; probably too impractical for the Zero; but, two of them could be put on a twin-SO8 adapter, with pin6 of each opamp lifted, & pin5 connected to the pad for pin6 - this way you bypass the output stage of the opamp -> more transparency.

OPA134 - well the OPA2134 and the OPA2132 could be worth trying in the amp. The stock OPA2604 is better for the DAC.

Wow thanks so much for that! Saved me some money there no doubt

Are you able to give a rough indication of tresholds for values to look out for on the spec sheet? (e.g. output current > ~x for the DAC, Ib < ~y for the headamp etc?)

[dsmudger]

Originally Posted by Normality

Sounds interesting, thanks! Do you agree that the LME49720 is a better opamp that the LM4562?

Yeah I would say so - beautiful highs, maybe a little cold but I kind of like it that way...

though I guess I probably didn't spend enough time with the 4562 (guess I dismissed them fairly quickly as inferior to the 49720, even despite its issues with slight lack of bass grunt and notch in the high mids I mentioned earlier ) - I'll see about popping it back in tonight and report back now I've spent some time with the all-49720 configuration - maybe two 4562 in the headphone section to see if that notch goes away, whether there's a price to pay in terms of clarity and so on...

[Henmyr]

My zero is now on the way, so I will try to get some samples from LT.

I have:
LT1364#CN8 x2
LT1361#CN8 x2
LT1057#ACN8 x2
LT1028#ACN8 x2
LME49720NA x3

Thinking about getting:
LT1469 x2
LT1358 x2

What else from linear would be good?

EDIT: I have browndog adaptor.

[king756]

WooHoo,

Just got my shipping number, it's on the way.

I've got lost in this thread with all the talk of swapping opamps etc.

Can someone explain how you swap these? Do you have to de-solder them and replace with a new one or do these simply just slot into a socket?

I will probably leave it stock for the time being and wait till people come up with some more definite recommended replacement combinations. It is good to know how to swap the opamps and what you are on about when you say dac opamp / headphone opamp....(are these two different circuits)?

[fault151]

Originally Posted by Normality

I couldn't but notice that the digital coaxial connector on the rear of the Zero is slightly 'crooked' (meaning not perpendicular). The same, but less evidently, for the volume knob. Anyone else have noticed this on theirs?



btw, 6th post in a row

no, but my volume knob is a bit noisy! Anyone elses?