Oh! IC

[gingertube]

Mabe I lucked out BUT
I was tracing the circuit of the local guitar god's favourite pedal. The IC had the markings ground off - still, got in there with the camera with the flash to document what I could, to my amazement, the information on the IC which had been ground off could be easily read on the picture I took with a flash.
Worth a try.

You should be able to work out what those op amps are. Very limited list of op amps have been used in guitar amps and most were of teh "general purpose" type which means that subs can be found readily.

Do you have a manufacure date - that would give us some clues.

Cheers,
Ian

[husky]

Long story short.. guy covered his work by dabbing a color coded dot on top of the ICs he used in my Hammond B3 chopper's custom preamp board.

There are 4. 2 with green dots, one red dot, one yellow dot. Nice. What a dick.

Is there any hope of discovering a range of IC series that would be purposed for such a thing? Close would be close enough, I AM GUESSING.

I guess a lot. I guess better than chance, on average. Too much chance and I am a loser!

Unless he also sanded off the info it will still be there. Use some acetone
Why do you need to know though? If you draw out the circuit you can figure out what will work usually. At least figure out where the power is (what pins) and you wont hurt anything. Also if you get it wet and use a magnifying glass even if it has been sanded you can usually see

[ampdoc1]

You call this a custom preamp. IF the rest of the circuit is not hidden, make a schematic of what you've got and it oughta' be pretty simple to figure out from what's going to/from the "black-boxes", what their functions are.

I wouldn't expect to see much besides op amps and/or a voltage regulator there.

[Reeltarded]

Sessions all weekend and then I can get in to take pictures, draw, and get measurement that may still exist.

The apprentice of the dead genius has vanished as well.

I appreciate the advice. Everything is changed except the tonewheel, the cap board/draws, and the manuals. Damn thing even has split matching transformer setup. It looks Martian in there. The board does have big trimmers on it, a pair. That tells me I probably have some output control if it is just a pair of op amps.

Thick plots are only fun on guitar rigs and mic amps and things like that. Yuck.

[Jpmas]

Long story short.. guy covered his work by dabbing a color coded dot on top of the ICs he used in my Hammond B3 chopper's custom preamp board.

There are 4. 2 with green dots, one red dot, one yellow dot. Nice. What a dick.

Is there any hope of discovering a range of IC series that would be purposed for such a thing?

Hi. I am new to this forum and saw your old post.
Were you able to figure out the IC's?
What were they? Does the preamp work now?
Thanks.