The "Best" Opamp - Opine Please

[jcx]

perhaps you care to explain what "value" you are deriving from laundry lists of devices without even the minimum notation of fet vs bipolar front end? - particularly when you seed the discussion with fet input devices? - no noise requirement? - you start with 3-4 MHz GBW devices: is your app going to have stability issues with 20-40-100 MHz devices? Need unity gain comp? Driving C load? …

without any context a "Best" part request is closer to a troll than a valid forum discussion topic

ps: sorry Evil, I was 1 min late, but I kinda was feeling Speaker should be encouraged to search for himself, (I did give self as a non-obvious search term) Or at least clarify the app context to make it possible to give meaningful advice

if we teach a fish to troll, can he lead us to water?

[KevinLee]

I have used AD8620 and to me it was not much better than OPA2134 or OPA2604.

I really like OPA627......and probably OPA2134 second.

[Mr Evil]

Originally posted by jcx
...but I kinda was feeling Speaker should be encouraged to search for himself...

I agree with that; it can become very repetitive when newcomers post the same few questions at regular intervals, but on the other hand, as a newcomer it can be a daunting task to sort through ten squillion search results stuffed full of conflicting, obscure, incomplete information buried beneath a ton of completely unrelated material, most of which is posts telling the original poster to search. I also think it worthwhile to linkify as much as possible, since having to search for a dozen different items from a post is time consuming when it would only take a second to turn them into links in the first place.

[rinox]

LF351, that have fet input (you can also remove the input cap)
Pratically umbreakble, for me the number 1 and very easy to find.

[speaker]

Originally posted by jcx
without any context a "Best" part request is closer to a troll than a valid forum discussion topic

ps: sorry Evil, I was 1 min late, but I kinda was feeling Speaker should be encouraged to search for himself, (I did give self as a non-obvious search term) Or at least clarify the app context to make it possible to give meaningful advice

if we teach a fish to troll, can he lead us to water?

I am sorry my request triggered you. "Best" seemed a valid way to state it and it did derive down to a couple of choices in a minimum of posts. I agree with you that "best" is fraught with bad connotations but I was not asking for the "Best" AC or speaker cable opinion. Did I search? Yes, and I found bits & pieces of what I needed after ~45 minutes or so. Certainly the whole picture could have been gotten if I spent more time and I would probably have learned far more too. I wouldn't call your post exactly encouragement to do that however.

speaker

[Bgt]

OPA627 and AD8610 are really nice audio chips. Use them both in my DAC's. Could not tell the difference soundwise.

[Nelson Pass]

Originally posted by Mr Evil
I would stay away from OPA604 (and 2604). Although the datasheet makes it look very promising, having gone thorough a lot of them over the last few years (bought a huge tube of them - bad choice) I have increasingly come to see that they are really no better than average at best. D. Self also comes to this conclusion via his distortion measurements.

I played with the 2604's and the first thing I ran into was
marginal stability at low gain settings, that is to say they
oscillated when your back was turned. Of course this seems
to be true of a lot of op amps, and so we tend to want to throw
away some feedback to be certain of their behaviour.

[tmblack]

If the OPA627 is too expensive, I recommend looking at the CA3130, you can take the ouput after the VAS and bypass any class AB/B output stage. Youcan add your own buffer or discrete output stage and get great sound.

Tom

[djk]

I find the OPA2604 to be a big improvement over the LF353/TL072 types.

Self says it measures poor? So what, its 50dB better than the LF/TL mentioned.

I still like the NE5532, especially for the $0.50 they go for, Self does too, just based on measurements.

The AD823 gets good press from some people I trust (James Bongiorno for one), on my 'try' list.

[Mr Evil]

Originally posted by djk
I find the OPA2604 to be a big improvement over the LF353/TL072 types.

Self says it measures poor? So what, its 50dB better than the LF/TL mentioned...

It's not just measured distortion that makes it poor; it's really not very good in any respect. I'm not talking measurements either, but practical experience. I have constructed circuits where its behaviour is simply atrocious, going way beyond just a few dB of extra distortion, such as a current-feedback amp I was testing which when using an OPA604 gave terrible distortions, both clearly audible and visible on the 'scope, yet even a lowly LF351 worked perfectly and almost every other op-amp I tried too.