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Review: ZERO 24 BIT/192KHz DAC/Headphone Amp/Pre-Amp - Page 59

post #871 of 9242
1/17/08 at 6:01pm
Thread Starter 
Quote:
Originally Posted by dsmudger View Post
LT1028 in the headamp? Penchum are you sure? i.e. isn't this the same mistake I made the other day? - seem to remember it was you (or maybe not - can't be fussed looking back through the thread ) who told me they're singles and so won't work, as somewhat surprisingly the headamp takes two duals? (don't think we've managed to establish the exact reason for this)

(or fault151: do you mean you had four of them on two browndogs running with the top open?)
Well, now I'm confused. Was it the LT1028 before? I just know that if he didn't have a lit LED on the headboard, it is most likely dead. This isn't what happened to you was it?
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post #872 of 9242
1/17/08 at 6:04pm
Thread Starter 
Quote:
Originally Posted by mapstec View Post
Well, the LT1028 is a single opamp and so you need the two you have on an adapter to replace any one of the opamps used in the zero.
So you would need 4 and two adapters for the headphone amp.


On a different note, I just switched the Zero to pure DAC duty and right now I am seriously underwhelmed!!

Strange ....

Please bear in mind, unit is just two hours running...

I will investigate further and keep you posted.
I did a search and this is what I found. I'm looking the number up as we speak.
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post #873 of 9242
1/17/08 at 6:08pm
hey guys, well after about ~ 150 hours I think I may be ready to roll opamps. I have never done that before, so any tips on how to do so properly (what tools to use, etc) are welcome.

also, if any would recommend what opamps to get it would be much appreciated.

I'm looking for something that will add a bit of that musical quality, really liquidy, larger soundstage, better/no-sacrifice in detail, something that doesn't lack in adding weigh/body to the sound.

any help is much appreciated!
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post #874 of 9242
1/17/08 at 6:09pm
Thread Starter 
Quote:
Originally Posted by dsmudger View Post
LT1028 in the headamp? Penchum are you sure? i.e. isn't this the same mistake I made the other day? - seem to remember it was you (or maybe not - can't be fussed looking back through the thread ) who told me they're singles and so won't work, as somewhat surprisingly the headamp takes two duals? (don't think we've managed to establish the exact reason for this)

(or fault151: do you mean you had four of them on two browndogs running with the top open?)
dsmudger, you are correct. This is a single. Must have two on a brown dog to use anywhere in the Zero. Sorry, I just didn't compute the number when I saw it! My bad...
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post #875 of 9242
1/17/08 at 6:27pm
Thread Starter 
Quote:
Originally Posted by Normality View Post
Hmm, replacing the OPA2604 for the LT1361 might do it for you.
Sure would be inexpensive.
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post #876 of 9242
1/17/08 at 6:41pm
Thread Starter 
Quote:
Originally Posted by Normality View Post
Btw, Penchum, what was that made you label the LT1361 "good" (for the Dac) like the OPA2604, & the LT1364 "great" ? The LT1361 should be a pretty significant upgrade over the OPA2604. Also, what did you like better about the LT1364?
This is where it got a little strange for me. the LT1361 in the DAC feeding the Super-T, the highs lost their definition. It held true no matter what I did, so I kept that rating. The LT1364 was just "everything" to the music. Clean clear highs, great mids, bass to die for. Like I said earlier, this was a unexpected surprise!

This brings me to another difficulty with having "any" kind of a rating system. If you were standing here with me, and hooked my Zero up to some amp you own, the results may be totally different. Headphone amps with Opamps in them pose a "challenge" all their own for this kind of rating system. I am totally willing to change my findings based upon others' testing. I have no ego to worry about when it comes to that table of Opamps. What do you think???
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post #877 of 9242
1/17/08 at 6:44pm
Quote:
Originally Posted by Penchum View Post
I forgot, what is your DAC feeding?
Oh sure - my setup:

17" Intel iMac
-USB-> Creative Labs Sound Blaster model: SB0270 -optical-> Zero
-USB-> Headroom Total Bithead
-> Grado RS1 (got some Senn HD580 and Shure e5c somewhere around the place as well/haven't tried 'em yet..)

(going to take the SB out of the loop when I get a chance to go get the cable that goes from the Mac's 3.5mm combined analogue headphone jack+optical out to the Zero's connector - never bothered to look round the back to see how the optical out worked until I was unpacking the Zero )
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post #878 of 9242
1/17/08 at 6:53pm
Thread Starter 
Quote:
Originally Posted by dsmudger View Post
Oh sure - my setup:

17" Intel iMac
-USB-> Creative Labs Sound Blaster model: SB0270 -optical-> Zero
-USB-> Headroom Total Bithead
-> Grado RS1 (got some Senn HD580 and Shure e5c somewhere around the place as well/haven't tried 'em yet..)

(going to take the SB out of the loop when I get a chance to go get the cable that goes from the Mac's 3.5mm combined analogue headphone jack+optical out to the Zero's connector - never bothered to look round the back to see how the optical out worked until I was unpacking the Zero )
Great! You should have those HD-580s out to help you determine which combination you like, especially when the "reverse" can sometimes play tricks on you. The HD-580s are stable phones, so when using the others and you run into a situation where: "I wonder if the highs are better this way round" happens, you can swap headphones to make the determination. Its an idea anyway.
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post #879 of 9242
1/17/08 at 6:58pm
Quote:
Originally Posted by Penchum View Post
Well, now I'm confused. Was it the LT1028 before? I just know that if he didn't have a lit LED on the headboard, it is most likely dead. This isn't what happened to you was it?
Right so that explains why it dint work for me then? Because it's a single op amp. I thought i had screwed up my zero for a minute when i heard the crack/pop.
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post #880 of 9242
1/17/08 at 7:00pm
Quote:
Originally Posted by Normality View Post
The LT1028 is single, the Solo requires dual opamps..

And btw, two LT1028 on an adapter would be another excellent upgrade, one that should make the Solo sound tubey.

The LT1361 won't do any damage to the amp. You should just measure the DC offset voltage on the outputs of the amp to make sure that everything's working fine. Checking that there aren't any 'bumps' in your headphones at power on & off is a way to have a first idea if there is DC on the outputs or not.


edit- think of it, I remember that when I saw the innards I thought that seemingly the Solo had DC blocking capacitors on the outputs
I guess i could take the two opa 627's of the adaptor and replace them with the LT1028 and put them in the solo to try. That would be ok wouldn't it?
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post #881 of 9242
1/17/08 at 7:02pm
Quote:
Originally Posted by Normality View Post
The LT1028 is single, the Solo requires dual opamps..

And btw, two LT1028 on an adapter would be another excellent upgrade, one that should make the Solo sound tubey.

The LT1361 won't do any damage to the amp. You should just measure the DC offset voltage on the outputs of the amp to make sure that everything's working fine. Checking that there aren't any 'bumps' in your headphones at power on & off is a way to have a first idea if there is DC on the outputs or not.


edit- think of it, I remember that when I saw the innards I thought that seemingly the Solo had DC blocking capacitors on the outputs
Hmm could you/anyone fill me in a bit on that DC offset thing? On mine I get two distinct pops at power on, the second one in time with the LED at the back of the DAC board coming on+click of the relay (pops aren't especially loud/not the full volume of the music when I switch to headphone and press play..) - is this anything to worry about/bad for my headphones?
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post #882 of 9242
1/17/08 at 7:03pm
Thread Starter 
Quote:
Originally Posted by fault151 View Post
Right so that explains why it dint work for me then? Because it's a single op amp. I thought i had screwed up my zero for a minute when i heard the crack/pop.
Naw, you should be ok. Unless you see a burn spot on the chip, then I'd toss it. Your Zero is pretty tough. Have you tried a different set you know works ok?
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post #883 of 9242
1/17/08 at 7:03pm
Quote:
Originally Posted by dsmudger View Post
Hmm could you/anyone fill me in a bit on that DC offset thing? On mine I get two distinct pops at power on, the second one in time with the LED at the back of the DAC board coming on+click of the relay (pops aren't especially loud/not the full volume of the music when I switch to headphone and press play..) - is this anything to worry about/bad for my headphones?
I noticed mine did this with some op amps and not others.
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post #884 of 9242
1/17/08 at 7:05pm
Quote:
Originally Posted by Penchum View Post
Naw, you should be ok. Unless you see a burn spot on the chip, then I'd toss it. Your Zero is pretty tough. Have you tried a different set you know works ok?
Yeh i just thought it must be either a fault or the wrong one for the zero headphone section. It's fine anyway, i tried another set up to make sure.
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post #885 of 9242
1/17/08 at 7:06pm
Thread Starter 
Quote:
Originally Posted by dsmudger View Post
Hmm could you/anyone fill me in a bit on that DC offset thing? On mine I get two distinct pops at power on, the second one in time with the LED at the back of the DAC board coming on+click of the relay (pops aren't especially loud/not the full volume of the music when I switch to headphone and press play..) - is this anything to worry about/bad for my headphones?
That is normal. The default is to always turn the volume down all the way, plug in the headphones and run up the volume. No biggie though. I do it out of habit, but I've also forgotten and had it pop without problems.
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