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Op Amp Fidelity

Started by Bio77, July 12, 2020, 04:15:57 AM

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Bio77

A lot of the older flangers and BBD delays use a 4558 Op Amps, which I love in a overdrive circuits but I want something cleaner in these type of circuits.  I often sub in OPA2134s.  I was looking for a ranking of fidelity for different Op Amps, does anyone have this?  Basically, I'm looking for a list with OPA2134 at the top and other Op Amps that might be good enough but not cost 5 bucks per below.

CodeMonk

I went looking for a site I saw several years ago.
Loads of info and comparisons of various OpAmps.
Unfortunately, I couldn't find it :(

But here are a few that may help:
http://blog.snapeda.com/2019/10/23/the-top-10-operational-amplifiers/
https://www.cycfi.com/projects/six-pack/op-amp-shootout/

Edit:
Found that site:
https://tangentsoft.net/audio/opamps.html
My friends call me Rob

Affiliations :
Dalton Jones Electronics: Chief Tinkerer

TFZ

Ideally you should always try to replace a BJT input opamp with the same type, and FET input with FET. Even though most "designers" of pedals probably have no regard for low noise design in the first place... For a BJT input opamp my usual choices are NE5532 and MC33078, for FET input just TL072 or TLE2072.

If you want to dive deeper into opamp fidelity here is a very thorough analysis of topologies and types: PDF.

Bio77

Awesome, thanks guys!

I did a bunch of reading last night.  I'm also liking the NE5532.

Scruffie

Quote from: Bio77 on July 12, 2020, 08:09:40 PM
Awesome, thanks guys!

I did a bunch of reading last night.  I'm also liking the NE5532.
It is a good chip but it has a lot of caveats, high current draw (wouldn't use it in effects with charge pumps) low input impedance (not great for input stages) and occasionally... just doesn't work right in circuits.

If you want cheap and low noise, the TL072 is nearly always the correct choice.
Works at Lectric-FX

jubal81

OPA1642. Texas Instruments audio opamp. Rail to rail. Low noise. Phase reversal protection. Get some SMD adapter PCBs and A/B test against the 072 and your jaw will drop. $2
"If you put all the knobs on your amplifier on 10 you can get a much higher reaction-to-effort ratio with an electric guitar than you can with an acoustic."
- David Fair

TFZ

Quote from: Scruffie on July 12, 2020, 08:20:33 PM
low input impedance (not great for input stages) and occasionally... just doesn't work right in circuits.
Could you elaborate maybe? Never had any problems with it and I'm not aware why it would have a low input impedance.

Quote from: jubal81 on July 12, 2020, 08:57:11 PM
OPA1642. Texas Instruments audio opamp. Rail to rail. Low noise. Phase reversal protection. Get some SMD adapter PCBs and A/B test against the 072 and your jaw will drop. $2
Yes, great part. When going for SMD there is also the OPA1678 which I am keen to try out. Also R2R, specced for audio and down to 5V and is 75ct in single units. Interestingly it is a MOSFET IC but manages to slightliy beat the OPA1642 in regard to noise.