Recommendations for Op Amps

[Peasey23]

Hi everyone,

This is my first post here, so apologies first and foremost for my steaming right in there, but hey. That's how I am.

I've been fighting with modding a Chinese Rat and having 'improved it' (subjective, naturally), killing it, bringing it back to life, kiling it, then swapped the 2.5 for 2.1mm power jack it's back again.

My next stage with it is to try and find a less common op-amp for it than the OP07cp it had in it and the LM308 - less noise and more well-rounded is what I'm after.

Any suggestions out there for opm amps that might work?

[Rixen]

Not so useful for subjective comparisons, but I've done a table here: https://docs.google.com/spreadsheets/d/1VjHWtAaqLJBZi7CKDw5SlzluXgqv__cc42lV0K1jMvQ/edit#gid=0
that compares parameters of interest to pedal builders. I have used the TL07x family as a benchmark, and a parameter that is *worse* than for that device is marked in red.

[Peasey23]

This is excellent and gives me a lot of potential experimentation, I think my next move will likely be to fit sockets and try a few out.

Thanks a lot!

[Kipper4]

Welcome Peasey23

[antonis]

Welcome Peasey23

What he said...!! 

Just to point out you have to tweak a bit compensator cap ( between pin 1 & 8 ) value according to op-amp slew rate..
(they are inversely proportional..)
You may use the formula: f_max = (Slew Rate) / (2*π*V_peak) for an initial estimation..

[ElectricDruid]

Welcome!

Thanks for sharing that list, Rixen. I hadn't seen that before.

One thing to note: not all the chips on that list are single op-amps, so they're not all direct replacements for the OP07CP in your pedal. There's still quite a few options though, and as Antonis says, you can also tweak it by altering the compensation cap.

[Peasey23]

Thanks for the welcome everyone! This is exactly the kind of forum I was looking for as I've dabbled in modding cheap pedals for a little while and I'm just starting to get my head around breadboarding my own versions of circuits.

Already seems to be a rich vein of knowledge!

With swapping out the op amp, my main goal is to find a straight replacement that helps reduce noise and my mod is essentially to make a crappy version of the Rat and level it up. I've swapped out the resistors for metal film, put in some NOS germanium diodes and a few cosmetics.

Upgrading the caps and Op amp swap and possibly transistor swap up next!