[FallenAngel]

Quote:

Originally Posted by leeperry /img/forum/go_quote.gif Single-to-dual Op-Amp Adapter (p/n 020302) 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

That's REALLY a stretch. If a SOIC to DIP adapter can make your opamp oscillate (which it actually could with some very extreme opamps), your board has to be SO well laid out and you must have SUCH great power supply bypassing that and you shouldn't be swapping them anyway.

As for signal loss in traces, you should be MUCH more worried about board layout and about a million other things before you even bother looking at how much signal you will lose in 2mm of opamp adapter traces.

It really sounds like you should reconsider your priorities, single-minded obsessiveness, although common in audio, is not a good thing.

 

[Cynips]

Quote:

Originally Posted by leeperry /img/forum/go_quote.gif Single-to-dual Op-Amp Adapter (p/n 020302) 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 see no reason whatsoever to think that any loss in these traces, which is even stated to be low as one of their good qualities, would add any discernible distortion - or even measurable for that matter. Anyone with such a claim will have to provide some evidence of measure if they're going to stand a chance at convincing me of distortion being added by the adapters.

Edit: I see FallenAngel pretty much said the same thing just better put

 

[FallenAngel]

Quote:

Originally Posted by Cynips /img/forum/go_quote.gif I see no reason whatsoever to think that any loss in these traces, which is even stated to be low as one of their good qualities, would add any discernible distortion - or even measurable for that matter. Anyone with such a claim will have to provide some evidence of measure if they're going to stand a chance at convincing me of distortion being added by the adapters.

Distortion and signal loss are different things, as is parasitic inductance.

Distortion would depend on the circuit and likely the result of instability.

Signal loss is definitely present - when you pull current through a trace that is smaller than required, you will have signal loss (or burn the trace though that's really not expected). In applications such as an opamp, this is REALLY minimal.

Parasitic inductance of the traces and the legs of the adapter itself may actually prove to be a problem for high-speed wide-bandwidth opamps that really need power supply bypassing very close to the signal pins. This should always be handled on the PCB but if you're talking about the "average" scenario of SOIC opamp on adapter plugged into DIP socket, it shouldn't be a problem. Of course if you're sticking a BJT-input opamp into a FET circuit, you're asking for trouble anyway and the adapter is the least of your concerns.

 

[Cynips]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif Distortion and signal loss are different things, as is parasitic inductance. Distortion would depend on the circuit and likely the result of instability. Signal loss is definitely present - when you pull current through a trace that is smaller than required, you will have signal loss (or burn the trace though that's really not expected). In applications such as an opamp, this is REALLY minimal. Parasitic inductance of the traces and the legs of the adapter itself may actually prove to be a problem for high-speed wide-bandwidth opamps that really need power supply bypassing very close to the signal pins. This should always be handled on the PCB but if you're talking about the "average" scenario of SOIC opamp on adapter plugged into DIP socket, it shouldn't be a problem. Of course if you're sticking a BJT-input opamp into a FET circuit, you're asking for trouble anyway and the adapter is the least of your concerns.

Even better put. Thanks for the clarification.

 

[murrays]

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.

If you know your chips are fried and you have some good sharp cutters you can cut the chip off leaving the legs soldered to the pads. It is then simple to unsolder each disembodied leg. However, be careful as the cutting force can push/pull the legs enough to dislodge the pads from the PCB.

 

[leeperry]

well, signal loss cannot be good...that was my meaning, I went from memory and it was 4:30AM

and I've just received some LT1057ACN8, gonna roll these anytime soon

 

[12Bass]

In most cases, the low-loss circuit board traces on an SOIC adapter likely have a negligible effect on the operation of audio op amps. Even a socket has a small amount of loss, as do the IC pins, and the traces on the PCB, and the component leads, and so on.... But that's making a big deal out of practically nothing. There are issues with layout to consider, but I think that worrying about adapters is probably OCD.

 

[ROBSCIX]

I think in the grand scheme of things, there are bigger things to worry about in almost any audio setup.

 

[leeperry]

Quote:

Originally Posted by 12Bass /img/forum/go_quote.gif I think that worrying about adapters is probably OCD.

it's all about the details! anyway, I'm not in the market for some new rolling at this point

and honestly, it might have been misjudgment...but nothing to do w/ OCD: Obsessive-compulsive disorder (OCD): Symptoms - MayoClinic.com

OCD is what makes ppl check 50 times a day whether the door is locked, or if the TV remote is at the exact place where it should be...this sort of things

 

[ROBSCIX]

..or wonder if their opamp is the best one they can get 150 times a day.

 

[12Bass]

FWIW, I'm at the point where I tend to accept all op amps as a compromise.... and generally spend more time listening to music than swapping chips. Do like the recent TI stuff though....

 

[ROBSCIX]

Sure, that is one way to look at it. You have gains in one area and short falls in another. I just use the ones that give me the closest signature to what I want.
I have also been testing the discretes units out there also.
Everybody has different tastes in sonic signature...

 

[leeperry]

ok I've just rolled the LT1057ACN8, I very much prefer the LT1364CN8

the SS is wider, but less natural....the mids aren't natural either, and the low end bass is AWOL.

they clearly sound one notch lower to me, ah....the mids are really wonky in comparison, "computer" sound is the best analogy I could come up w/, it sounds like a Soundblaster or sumthing...and the sound is very reverb'ed, it feels totally unrealistic(like an empty room w/ nothing remaning in the middle channel, all the audio went to the side channels). these are not going to stay

next on the list are LT1361/LT1469

 

[ROBSCIX]

Quote:

Originally Posted by 12Bass /img/forum/go_quote.gif FWIW, I'm at the point where I tend to accept all op amps as a compromise.... and generally spend more time listening to music than swapping chips. Do like the recent TI stuff though....

Have you tested out any of the discretes out there?

 

[ecclesand]

Quote:

Originally Posted by leeperry /img/forum/go_quote.gif ok I've just rolled the LT1057ACN8, I very much prefer the LT1364CN8 the SS is wider, but less natural....the mids aren't natural either, and the low end bass is AWOL. they clearly sound one notch lower to me, ah....the mids are really wonky in comparison, "computer" sound is the best analogy I could come up w/, it sounds like a Soundblaster or sumthing...and the sound is very reverb'ed, it feels totally unrealistic(like an empty room w/ nothing remaning in the middle channel, all the audio went to the side channels). these are not going to stay next on the list are LT1361/LT1469

And you came to this conclusion with the LT1057 after having them for only a few hours? Did you burn them in at all? I found it does make a difference. You may want to give it a try.