[Penchum]

Quote:

Originally Posted by uds /img/forum/go_quote.gif Ok, after reading to page 20, I am kinda confused... I can't even think how to phrase my question. How many OpAmps are in the Zero? Like, how many can be replaced by something better? And what OpAmps should I get(for Prog Rock/Metal) for what part of the Zero(Meaning DAC and Amp sections)? This is probably much simpler than I am making it out to be, but I just got my self incredibly confused.

No problem. It is confusing at first.

The stock Zero comes with one "dual" Opamp (one chip) in the DAC section. It has two "dual" Opamps (two chips) in the headphone amp section, one for each channel, L & R.

The signal is first amplified/colorized by the DAC section and either goes out to the RCA's on the back for use in another amp, or goes to the internal headphone amp for further amplification. The headphone amp "colorizes" the signal further as it amplifies it to headphone levels. This is why you will see folks posting about changes in the SQ based on both DAC & headphone amp Opamp changes. In the case of the "single" Opamps like the OPA627BP's, it takes two "single" Opamp chips on an adapter, to equal a "dual" Opamp.
Does this help, or did I mess it up?

 

[[S]uds]

So, in the end, I would need 6 OpAmps(or 3 dual OpAmps) to replace the stock ones? And a BrownDog Adapter for each single OpAmp to place 2 of them on?

 

[Penchum]

Quote:

Originally Posted by uds /img/forum/go_quote.gif So, in the end, I would need 6 OpAmps(or 3 dual OpAmps) to replace the stock ones? And a BrownDog Adapter for each single OpAmp to place 2 of them on?

That is correct. However, not too many have tried singles in the headphone amp section. The "duals" seem to work great in the headphone amp section.
I just double checked my Zero #1 I have hooked up to my mini-system, for SQ. It has OPA627's on the adapter, in the DAC section and two LT1364's in the headphone amp section. Using the Zero's built-in headphone amplifier, this combination is really great with my HD-650s! I haven't listened to it for a while, and it is refreshing to have a decent SS sound built-in!

 

[[S]uds]

Do you have any recommendations for easily obtained OpAmps that work well with HFI-780/Grado SR225? Something that can take the fun sound of these cans, but at the same time make it more detailed, maybe tame the treble a bit?

Also, thank you for all the help. I'd be lost without your explanation of the OpAmps.

 

[Penchum]

Quote:

Originally Posted by uds /img/forum/go_quote.gif Do you have any recommendations for easily obtained OpAmps that work well with HFI-780/Grado SR225? Something that can take the fun sound of these cans, but at the same time make it more detailed, maybe tame the treble a bit? Also, thank you for all the help. I'd be lost without your explanation of the OpAmps.

No problems.

I would try the stock Opamps first and burn-in the Zero for 100hrs. At that point, you might try the LT1364 in the DAC and LT1469's in the headphone amp. If all else fails to do the trick, then I'd try the OPA627's on an adapter in the DAC, with LT1364's in the headphone amp.

The burn-in is pretty important, so you can hear the changes of the Zero and have a "reference" point when it's done maturing. This will make the evaluation of other Opamps go a little easier for you. Don't be surprised if you like the stock Opamp sound. About 1/2 of our Zero owners are still using the stock Opamps.

Have a good one!

 

[pincellone]

Quote:

Originally Posted by pincellone /img/forum/go_quote.gif Well, not that much, I guess it's about $90 for a couple including the adapter. Expensive but still not overexaggerated, considering the current availability. If Eddie still has them in stock, I don't think they will be that cheap for long...

Nearly two months ago, I told you what was going to happen to the 627BPs...

I hope that those of you who were trying to save a few bucks didn't get the fake ones.

 

[Penchum]

Quote:

Originally Posted by pincellone /img/forum/go_quote.gif Nearly two months ago, I told you what was going to happen to the 627BPs... I hope that those of you who were trying to save a few bucks didn't get the fake ones.

If someone does, I hope they will give everyone an idea on how they sound different. If copied correctly, they may sound very close to the originals and still be worth the cheap price. Not that I condone buying such things, but "maybe" those who end up with a set, will not be too disappointed. Fingers crossed!

 

[pincellone]

Quote:

Originally Posted by Penchum /img/forum/go_quote.gif If someone does, I hope they will give everyone an idea on how they sound different. If copied correctly, they may sound very close to the originals and still be worth the cheap price. Not that I condone buying such things, but "maybe" those who end up with a set, will not be too disappointed. Fingers crossed!

IMHO they're not 627BPs clones. The fakers didn't even manage to copy them exactly the same on the outside... so thinking that 627BPs have been reverse engineered to replicate them sounds too much optimistic to me.

Very likely they are cheap opamps rebranded with a fake logo.

 

[Penchum]

Quote:

Originally Posted by pincellone /img/forum/go_quote.gif IMHO they're not 627BPs clones. The fakers didn't even manage to copy them exactly the same on the outside... so thinking that 627BPs have been reverse engineered to replicate them sounds too much optimistic to me. Very likely they are cheap opamps rebranded with a fake logo.

Ya, I hear ya. Wash off the cheapo, put on new paint. That would suck.

 

[wquiles]

Quote:

Originally Posted by pincellone /img/forum/go_quote.gif Nearly two months ago, I told you what was going to happen to the 627BPs... I hope that those of you who were trying to save a few bucks didn't get the fake ones.

I missed this earlier. How cheap where these 627BP's? Out of Ebay perhaps? How can you tell they where cheap clones?

Perhaps something like these are not "real":
Burr Brown OPamp Op amp OPA627BP OPA627AP OPA627 2pcs - eBay (item 360043516202 end time Apr-25-08 20:19:43 PDT)

or

Matched Pair Burr Brown OPAmp OPA627BP OPA627 OPA637 - eBay (item 140212567895 end time May-02-08 11:04:26 PDT)

I just want to be informed in case I finaly decide to buy some one of these days!

Will

 

[biko]

Quote:

Originally Posted by pincellone /img/forum/go_quote.gif IMHO they're not 627BPs clones. The fakers didn't even manage to copy them exactly the same on the outside... so thinking that 627BPs have been reverse engineered to replicate them sounds too much optimistic to me. Very likely they are cheap opamps rebranded with a fake logo.

I think it's safer going SOIC or TO-99 instead of PDIP.

Everybody can handle PDIPs and put them into a browndog. There is enough demand so it's profitable to counterfeit them. The top side of the package is bigger, so it's easier to sand blasting the markings and reprint them.

 

[souperman]

Quote:

Originally Posted by wquiles /img/forum/go_quote.gif I missed this earlier. How cheap where these 627BP's? Out of Ebay perhaps? How can you tell they where cheap clones? Perhaps something like these are not "real": Burr Brown OPamp Op amp OPA627BP OPA627AP OPA627 2pcs - eBay (item 360043516202 end time Apr-25-08 20:19:43 PDT) or Matched Pair Burr Brown OPAmp OPA627BP OPA627 OPA637 - eBay (item 140212567895 end time May-02-08 11:04:26 PDT) I just want to be informed in case I finaly decide to buy some one of these days! Will

From the pictures those seem to be real. Also tube_buyer is a reputable company.

 

[CountChoculaBot]

I don't trust the first guy kind of. Mostly because he's from Hong Kong, though.

 

[souperman]

Quote:

Originally Posted by CountChoculaBot /img/forum/go_quote.gif I don't trust the first guy kind of. Mostly because he's from Hong Kong, though.

...like I said...they are pretty reputable.

 

[Penchum]

Quote:

Originally Posted by souperman /img/forum/go_quote.gif From the pictures those seem to be real. Also tube_buyer is a reputable company.

I went back and checked, and I was wrong. I got my first set from Lawrence and my second set from tube_buyer. So, I guess I have some checking to do. The second set came about a month ago, and look like the ones in his pic.