Favorite Rat Mods?

[Chuck D. Bones]

That's normal.

Agreed. The Rat has enough gain to drive the opamp deep into saturation. Some people like that. Other folks prefer lower gain settings. If you're not setting GAIN above noon, then an A25K GAIN pot will be more to your liking. It's my understanding that the original designer tuned the Rat to sound good with a Strat. If you're hitting it with Humbuckers, then it's gonna sound farty.

you can also try the Ruetz mod, which lowers the gain in the mid frequencies.

A real LM308 will sound better than an OP07 in this circuit.

 

[Nostradoomus]

Truth.

 

[xconverge]

Fun stuff then, I put a socket for the compensator cap in case I end up with an lm308, I also changed the 4.7uf C2 cap to 2.2uf and it sounds fine

I couldn't really find any confirmation anywhere that what I was experiencing/hearing was normal, so I am glad you both say it is! It was my first PCB I designed/manufactured to learn the process and I HEAVILY referenced the muroidea version...

I will just keep between 9-12 oclock for distortion which is definitely what I prefer anyways. Or I could stop messing about and practice guitar? ...but that sounds like hard work compared to disassembling the pedal again and reworking portions of it

 

[Nostradoomus]

2.2uf works too. Also if you just don't dig in with your pick as hard that helps. I always have my distortion up to 10 so had to find a solution.

 

[jimilee]

Agreed. The Rat has enough gain to drive the opamp deep into saturation. Some people like that. Other folks prefer lower gain settings. If you're not setting GAIN above noon, then an A25K GAIN pot will be more to your liking. It's my understanding that the original designer tuned the Rat to sound good with a Strat. If you're hitting it with Humbuckers, then it's gonna sound farty.

you can also try the Ruetz mod, which lowers the gain in the mid frequencies.

A real LM308 will sound better than an OP07 in this circuit.

I did not realize the strat part. Now I must experiment.

 

[cdwillis]

I like the taper of a linear pot for the Filter control. It just feels more usable to me.

If I'm only using the regular silicon clipping diodes I like having a linear pot for the volume control too. If I'm using red LEDs instead of silicon diodes for clipping the logarithmic volume pot is fine.

 

[Feral Feline]

For more bassification, check out Gord Tranter's mods...

 

[xconverge]

Do I really want to find a legit lm308...hmm... You guys almost convinced me... I doubt I will hear a difference but also have a sick curiosity

 

[xconverge]

Found one local to me and grabbed it, it was not genuine, nice

I think I will just give up on this and stick with the op07 for my own sanity

 

[andrewsrea]

I have done a lot of the aforementioned mods. I have been using LM308 NOS (metal cans) and use a 47pF to 82pF c3 compensator cap to slow down the slew rate a little more (IMHO, the 'blur' from the IC and the crunch from the clipper diodes are the signature sound). I also go a little heavier on the C4 bypass cap, since there is so much treble on tap with a stock Rat. 200pF to 330pF, depending on how it is sounding. I use a DPDT to switch between 1n4841's or D9E's (single symmetrical pair of each type).

For some reason, I play a Rat and love it then quickly tire of it. Especially in the context of a song. Then again, I don't get along too well with fuzz and this is a cross between a distortion and a fuzz.