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Review: ZERO 24 BIT/192KHz DAC/Headphone Amp/Pre-Amp - Page 91

post #1351 of 9226
2/6/08 at 11:57pm
Thread Starter 
Quote:
Originally Posted by bada bing View Post
I've been doing some rolling in my Zero.
One warning I have is that in my Zero, the LT1364 is exhibiting some signs of hi- freq oscillation. When used in the DAC section, LT1364 (two different chips) ran hot and also caused the LT1469's I had installed in the Amp section to run hot. The sound was okay, a touch too bright and the audible volume was somewhat diminished. It may be an issue with my board or it may be that LT1364 is borderline unstable in the Zero. Other than the issue with LT1364's my zero is impressing me.

Just a heads up for others rolling their zeros. High performance op amps can have issues in some amps and not others of the same version - like the old Pint portable and 8697's
Wow! That's a first! Question? Is your Zero broke in yet, or did you start swapping right away?
Thanks!
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post #1352 of 9226
2/7/08 at 1:09am
It has about 30 hours on it.

The telltale that something is amiss with the LT1364 in the DAC is not that the LT1364 runs hot, but that it makes the LT1469's in the amp section run hot at equivalent volume level. When the 1364's (I tried both I had) were replaced with any other option, the LT1469's run much cooler. The LT1364 is throwing some inaudible oscillations downstream and loading the amp board. The sound isn't greatly hampered, although the combination isn't "great".

I don't necessarily think this is a problem for all Zero's, but mine does not like the LT1364. I don't believe there is any real defect in my unit, it sounds fine (actually better than fine) and I spent 15 minutes with a DMM checking everything that was obvious. Probably just a bit touchier than most Zero's about ultra fast opamps in the DAC section. I'm liking OPA627 in the DAC and LT1469 in the amp for now.

If you check the data sheet, the LT1364 is about as fast an opamp as is commonly available - 1000v/uS and probably is a bit touchy even though it is listed as unity gain stable.

If anyone else uses the 1364 in the DAC and 1469's in the amp, check the chip temps. If the 1469's are pretty warm, drop something besides a 1364 in the DAC and see if the 1469's don't cool off some without a change in volume. That is a give away there is some inaudible ultrasonics in the signal heating up the amp section.
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post #1353 of 9226
2/7/08 at 1:21am
Thread Starter 
Quote:
Originally Posted by bada bing View Post
It has about 30 hours on it.

The telltale that something is amiss with the LT1364 in the DAC is not that the LT1364 runs hot, but that it makes the LT1469's in the amp section run hot at equivalent volume level. When the 1364's (I tried both I had) were replaced with any other option, the LT1469's run much cooler. The LT1364 is throwing some inaudible oscillations downstream and loading the amp board. The sound isn't greatly hampered, although the combination isn't "great".

I don't necessarily think this is a problem for all Zero's, but mine does not like the LT1364. I don't believe there is any real defect in my unit, it sounds fine (actually better than fine) and I spent 15 minutes with a DMM checking everything that was obvious. Probably just a bit touchier than most Zero's about ultra fast opamps in the DAC section. I'm liking OPA627 in the DAC and LT1469 in the amp for now.

If you check the data sheet, the LT1364 is about as fast an opamp as is commonly available - 1000v/uS and probably is a bit touchy even though it is listed as unity gain stable.

If anyone else uses the 1364 in the DAC and 1469's in the amp, check the chip temps. If the 1469's are pretty warm, drop something besides a 1364 in the DAC and see if the 1469's don't cool off some without a change in volume. That is a give away there is some inaudible ultrasonics in the signal heating up the amp section.
Ow, I agree with you. Something is up. But, your Zero isn't burned in yet either. I'm not sure how much or if at all, this could be playing into the audible part, not the heat part. I forget now what the temp was exactly, but the LT1469 was tested up to like 200c without artifacts or anomalies. I'm just concerned that your Zero hasn't had time to mature yet, that's all.
Maybe if you ran a different Opamp for now, then came back to it after 100hrs and see if the Zero gets along better with it, or not. I think it's worth a try.
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post #1354 of 9226
2/7/08 at 2:19am
Hi I'm new to the thread, is there any published measurements on this DAC?
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post #1355 of 9226
2/7/08 at 2:23am
Thread Starter 
Quote:
Originally Posted by Dept_of_Alchemy View Post
Hi I'm new to the thread, is there any published measurements on this DAC?
Hi DoA, this is the "safe" source to purchase from on ebay, he has all the specs on there too: ZERO 24/192 DAC D A CONVERTOR , HEAD FI AMP , BRAND NEW - eBay (item 330209257065 end time Feb-09-08 16:34:36 PST)

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post #1356 of 9226
2/7/08 at 2:27am
Thread Starter 
Quote:
Originally Posted by Dept_of_Alchemy View Post
Hi I'm new to the thread, is there any published measurements on this DAC?
I've got one of mine under my MKIVse and the other under my MKV! They are almost exactly the same width and depth is almost the same as the MKIVse.
Very nice little units for sure! Let me know if you need more info!
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post #1357 of 9226
2/7/08 at 2:39am
Quote:
Originally Posted by Penchum View Post
Ow, I agree with you. Something is up. But, your Zero isn't burned in yet either. I'm not sure how much or if at all, this could be playing into the audible part, not the heat part. I forget now what the temp was exactly, but the LT1469 was tested up to like 200c without artifacts or anomalies. I'm just concerned that your Zero hasn't had time to mature yet, that's all.
Maybe if you ran a different Opamp for now, then came back to it after 100hrs and see if the Zero gets along better with it, or not. I think it's worth a try.
When I tested the 1364 in the DAC on my Zero, it ran hot. I only tested the DAC section and left the stock opamps in the headphone section. I had broken in my Zero for over 200 hours before rolling the DAC chip (1364). I did not like it and settled on the 1469 as DAC for now with the 1361's in the headphone section. This I DO like and I am breaking the 1469 in for awhile before trying another chip.
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post #1358 of 9226
2/7/08 at 2:43am
Thread Starter 
Quote:
Originally Posted by edguetzow View Post
When I tested the 1364 in the DAC on my Zero, it ran hot. I only tested the DAC section and left the stock opamps in the headphone section. I had broken in my Zero for over 200 hours before rolling the DAC chip (1364). I did not like it and settled on the 1469 as DAC for now with the 1361's in the headphone section. This I DO like and I am breaking the 1469 in for awhile before trying another chip.
Yep. I think that was a great combo too. It has really good low end, right?
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post #1359 of 9226
2/7/08 at 2:49am
Yeah! I really like the bass in this combo. For me, it is tight and well defined. I can hear the bass guitar notes cleaner and clearer in relation to the drums in rock music.

Can still hear the pick on the strings as well. Good residual on notes and it doesn't muddy up the mids for me. Still not "perfect" but very satisfying!

Good night!
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post #1360 of 9226
2/7/08 at 6:42am
Quote:
Originally Posted by Penchum View Post
I've got one of mine under my MKIVse and the other under my MKV! They are almost exactly the same width and depth is almost the same as the MKIVse.
Very nice little units for sure! Let me know if you need more info!
I did have briefly my Zero under my LD and I think that may have cause the OPA627 to broke and DY2000 to malfunction. MKIV SE makes a lot of heat throughout the case and it warms the already warm Zero even more. I have to make some kind of rack for them to allow the air circulate freely.
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post #1361 of 9226
2/7/08 at 9:44am
Thread Starter 
Quote:
Originally Posted by Seba View Post
I did have briefly my Zero under my LD and I think that may have cause the OPA627 to broke and DY2000 to malfunction. MKIV SE makes a lot of heat throughout the case and it warms the already warm Zero even more. I have to make some kind of rack for them to allow the air circulate freely.
I'll be darned! I'll check that out today with my temp gun. I don't want to have my own "meltdown" here in my home office!
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post #1362 of 9226
2/7/08 at 1:49pm
i upgraded my soundcard finally



the bass has never been deeper, and never this clear, im not sure if it's placebo but it seems now that the Zero is sounding better than ever.

gift and a curse though, my mo3s sound crap now all of a sudden, but my flacs are seem clearer. heh.

opamp rolling next!!
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post #1363 of 9226
2/7/08 at 2:32pm
What is the most natural, neutral, cleanest, airiest, most uncolored, good bass presence and texture, not overpowering treble, most transparent and purest op-amp combination for the zero you've(anyone) found yet? Natural and airy and clean are key-words.

I just can't seem to get the sound to be all that. My previous best combination was LME49720(dac) + LT1469(amp), but I sensed a very slight warm coloration in the mids and a small flowing effect which devoured a lot of the air (the flowing effect(made the music "flow" effortless) was very pleasant, but the slight air lost made it very hard to breath), so in the end I couldn't stand it and had to change.

The stock does a lot of things right, but I want a little bit more detail, but the coloration, or UNcoloration is very good, as is the air.

My favorite (for the moment) favorite combination is LT1469(dac)+LME49720(amp) and it sounds very good, but I think I hear the slight midrange coloration of the LT1469 shine through.

It might be that in the end, beyers, grados/alessandros, or me in general just don't love the LT sound, so I might have to turn to OPA627 or similar.

Any suggestions?
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post #1364 of 9226
2/7/08 at 3:13pm
can i use LT1469 in dac and also in headphone amp? three lt1469 in the zero.
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post #1365 of 9226
2/7/08 at 4:42pm
I use LT1469 in my dac for the moment, but it is really really hot. If I touch it with my finger I will burn myself, thats how hot it is. Is that bad? I have the LT1469IN8 so it should withstand higher temperature than LT1469CN8 but still.
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