The Opamp thread

[leeperry]

Quote:

Originally Posted by ecclesand /img/forum/go_quote.gif Needless to say, my first set of OPA1611s died an untimely death. [..] I will give them a proper funeral.

anyway, it's good that we all have a favorite now....up to now they all left me craving for more.

and I agree w/ Slash47, I prefer the 2132P over the 2134P(stock on my card)....but again, I only used them on $150 soundcards where the 4562/49720 always sounded terrible(huge dull SS, anemic bass on the NA/MA and resonating mids)

PS: damn the SS of "Edwyn Collins - A Girl Like You" sounds really awesome on the LT1364

 

[ROBSCIX]

Quote:

Originally Posted by ecclesand /img/forum/go_quote.gif I'm still waiting on the 49710HA singles. I ordered enough to ensure if I screw something up, I have some backups. With the 1611s, soldering to the bottom of the adapter (between the pins) was much easier than I thought it would be. However, while soldering the top chip (which should be easier than the bottom), I ran into a problem and actually lifted one of the traces off the bd adapter and bent one of the pins on the opamp. I think the adapter was bad....yeah, that was it...bad adapter. Anyway, I was able to repair the trace with some solder. Popped it into my DAC and nothing. Reflowed the solder on the repaired trace and still nothing. Looked at my other bd adapters and the other set of OPA1611s I had and realized there were markings indicating which way the chips should be soldered. Huge DOH!!!! Needless to say, my first set of OPA1611s died an untimely death. I will try to desolder them, but I'm not optimistic. I will give them a proper funeral. After CORRECTLY soldering the second set, they work splendidly. I will give impressions after about 40 hours of burn-in. That was how long I estimate it took for the 1612 to settle in and blossom.

Bummer, mistakes happen sometimes. Post your impressions once you get your testing done. I might build a set of 1612's later on today but I am still testing the 1611's I built.
To note, on the BD adapters, some of the pads are not connected to any traces and as such are very easy to pull off with a little heat. Especially on the dual single SOIC8 to dip 8 adapters.

 

[12Bass]

FWIW, I didn't notice much (if any) difference between 2 x OPA211 and the OPA2211A....

Anyone compared OPA1611/12 with OPA211/2211A? There appears to be some confusion about the relationship between these parts. Some suggest that the OPA1611/12 have been improved somewhat, while others say that they are merely the OPA211/2211A with relaxed DC specifications and at lower cost.

 

[ecclesand]

Quote:

Originally Posted by ROBSCIX /img/forum/go_quote.gif Bummer, mistakes happen sometimes. Post your impressions once you get your testing done. I might build a set of 1612's later on today but I am still testing the 1611's I built. To note, on the BD adapters, some of the pads are not connected to any traces and as such are very easy to pull off with a little heat. Especially on the dual single SOIC8 to dip 8 adapters.

Yeah...I don't think it was the pad that caused them not to work. It was me putting them on backwards. I tried to desolder them with some braid and with a solder pump. Not enough patience so I tossed the entire module.

 

[ROBSCIX]

I have both yet (1611 and 211) I have never compared them directly. Some of the specifications are similar..IIRC.

 

[ROBSCIX]

Quote:

Originally Posted by ecclesand /img/forum/go_quote.gif Yeah...I don't think it was the pad that caused them not to work. It was me putting them on backwards. I tried to desolder them with some braid and with a solder pump. Not enough patience so I tossed the entire module.

No, that is not really what I meant. I meant on certain brown dog adapters, I find you can pull of certain pads very easily especially the ones that are not connected to traces. I am just mentioning it as I have seen it happen before.
Putting them on backwards and powering them up would toast the opamp almost immediately.

 

[FallenAngel]

Quote:

Originally Posted by SpudHarris /img/forum/go_quote.gif ^Well in my set up with Class A Adapters they absolutely do. Edit: There is much said within this thread about the benefits of single opamps compared to duals i.e. better channel separation, class A Biasing etc, etc.... I'll give the LME49710 / 49720 as another opamp comparison, the difference between the two is noted and even more so with the TO-99 versions. It is also worth mentioning that the OPA132 is said to be an 'updated' version. The margin of difference between the OPA132's and 2132 is the largest I've seen between a single and dual within the same family. I'm no techie but I do have a critical ear (as do most here) and can only speak as I find.

Class-A biasing is easily done on dual or single chips, same principle.

I think stating that there is better channel separation in single opamps vs duals is a joke - a dual opamp has the exactly same amplifier as the single, but two in one package with power pins shared. Considering power is shared in almost all amp designs, this is exactly the same thing anyway.

As for TO-99 version of opamps, the only person I've seen say anything about that is Andrea, and he argues for the sake of arguing with little to back it up. Or maybe he hears completely differently than I do and that's another story.

I have a pair of OPA132's on an adapter and a single OPA2132, I can't tell the difference between them at all. Not one bit, zip, nada, nothing, completely identical. I'm testing this in a CMOY I whipped up as well as 3-channel modified Sijoase Class-AB amp.

 

[12Bass]

One trick which might help in removing SOICs is flooding both sides with solder, then quickly flicking the chip away while the solder is still molten. Takes some doing, but works better than desoldering, IME. Desolder the pads with braid afterward.

 

[ROBSCIX]

Quality desoldering tool may also be a good addition to your tool box.

 

[crapback]

I bought one of these. Amazon.com: Aoyue 701A+ Dual Function Soldering and Desoldering Station: Home Improvement I still haven't figured out exactly how to get the thing to work right.

leeperry, any chance you might be auditioning the 1361's soon? I'm still kinda itching to get someone else's opinion of them. That and I need to have my sanity double-checked every once in a while.

 

[leeperry]

Quote:

Originally Posted by crapback /img/forum/go_quote.gif leeperry, any chance you might be auditioning the 1361's soon? I'm still kinda itching to get someone else's opinion of them. That and I need to have my sanity double-checked every once in a while.

are they really really good? sell them to me

it's prolly a bad impression, but I don't think these cheapo browndog adapters do any good to op-amps...they increase distortion, that's what their website says. I was expecting a lot from the LME49722, and it fell flat...and so did the THS4032 everyone raves about for my HD2 board.

 

[ROBSCIX]

Why would they increase distortion?

 

[ecclesand]

Quote:

Originally Posted by ROBSCIX /img/forum/go_quote.gif Why would they increase distortion?

I was just going to ask the same thing. I also checked their website and can't find anything related to distortion. Can you provide a link?

 

[leeperry]

Quote:

Originally Posted by ecclesand /img/forum/go_quote.gif I also checked their website and can't find anything related to distortion. Can you provide a link?

Single-to-dual Op-Amp Adapter (p/n 020302)
Quote:

Low loss traces

it's not too far stretched to think that any theoritical advantage of going 2*single might be overcome by the "loss" due to these cheapo adapters.

I believe someone knowledgeable in this thread said that they could easily make op-amps oscillate, where some much more pricey adapters would not.

I don't think there is much to be expected from a $2 adapter...but well, maybe someday I'll be blown away by some chips on these adapters the same way the LT1364 does it to me atm

both the LT techsupport and Andrea advised it to me, and I can hear why...it really scales well, the more amazing the recordings the more natural they sound

 

[SpudHarris]

I use these because the Brown Dogs are sometimes too wide to fit 2 off right next to each other which is the set up in my P3 & P3+. I've used both but these are far better quality than Brown Dogs. Only thing is you have to solder the pins yourself as they come in a flat kit (see pics).