Informant Drive tweaks

[Orson Anton Welleson]

I finished the Informant drive over a week ago. It is nice enough, but it didn't grab me. Everything that made the Rat so enjoyable is missing from the ID.

I've heard people talk about trying other op-amps. I think that's my next move. I'm assuming the LM308 would work. The idea being to give the circuit some of the snarl and bite of its progenitor.

Any thoughts from anyone else underwhelmed by the ID?

 

[Fama]

I'm assuming the LM308 would work.

It won't - the informant has two TL072 dual op amps and a charge pump, the LM308 is a single op amp.

You could try a different dual op-amp but I suspect the difference won't be that big.

If you can identify what it is you don't like and would like more, then you could tweak other parts of the circuit. I wasn't a huge fan either (at least on a strat), I tried kludging in an extra low pass filter in the middle of the circuit (it was too bright on a strat, for my taste), but it didn't work very well. I probably should have put in something before the main circuit itself (although the buffer makes that annoying), since turning the tone control down worked fine for me, but I just sort of gave up on it. Maybe I'll revisit it at some point.

 

[Orson Anton Welleson]

Hmm, okay. I thought one of those two TL072 was for the buffer. Back to the schematic then.

It's really simple. The Rat has more bite, more mids, which is a big part of that bite, and more harmonics. I'll revisit it one day down the line. Until then, it's to the box of disappointing or boring effect boxes. It's a box full of things that were disappointing, or are in need of repair.

 

[Fama]

Hmm, okay. I thought one of those two TL072 was for the buffer. Back to the schematic then.

Oh, do you mean you would replace one of the TL072 with an LM308 and also skipping the buffer? That would work op amp stage wise, but a.) not sure if the pinouts are compatible, b.) you need a compensation cap for an LM308 I believe, and c.) you would be changing the first stage of the pedal which is not the doing the heavy lifting, so I still don't think it would make a big difference in sound.

If you want more bite and more mids, switching out the op amp is not going to get you that.

 

[Orson Anton Welleson]

That was the idea. I didn't expect anything in particular from changing the op amp, except possibly possibly imparting some Rat-like qualities, making it a bit less polite.

I'm guessing that since most of these LM308 are Chinese fakes, that explains what I've noticed, namely that different fake LM308s have different audio qualities from each other. This is in the same circuit, of course. Meaning that Rat clone "A" has a fake LM308 of a given source. I swap it out for another brand of fake LM308, in clone "A"and it sounds somewhat different from the original LM308 the pedal came with.

Someone will almost inevitably tell me this can't be so, but it was aurally conspicuous with two different Rat circuits I have here.