ilovefuzz.com

So I picked up a Rat2 with a LM308n chip in it from FooManFat here a while ago and the volume pot shaft broke. so I'm ordering the replacement pots (all 3) from small bear electronics, but while I'm in there I wanted to try and accomplish something that I'm not sure is possible without massive mods. I would like to keep the stock tone but get rid of the low end cut... I know that the reutz mod helps bring back in some low end, but it also decreases gain. So does anyone on here know of a simple mod that would reduce the low end cutoff? Basically make it more bass friendly, without destroying the original character of the pedal?

ok I think I can help. I'm just shootin from the hip but I have pretty good luck getting what I want.

http://www.beavisaudio.com/schematics/Images/Proco-Rat-II-Schematic.png

increase C3 and C13 to maybe 47nf or 100nf
change C7 to 1uf
change R7 to 1K
change R8 to 220R

note that C3 on this schematic might not be C3 on your PCB or any other schematic. due diligence is required.

Dude, thank you so much!!! I was also thinking of changing c6 to 10uf as that's the low frequency section of the feedback loop, from what I've found randomly searching different forums lowering c6 decreases low end and tightens it up which is exactly opposite of what I'm trying to do so I figured going higher would increase the low end as well.

Ancient Astronaught wrote:I was also thinking of changing c6 to 10uf

completely unnecessary. without getting too technical and stuff, you can pretty much make a statement that 4.7uf and 10uf are sucking frequencies lower than your guitar can produce to ground. the reason they even affect your low E at all is because they blanket such a wide range of frequencies. increasing the resistor over that 4.7uf does a great job of decreasing this bass + mid blanket suck. changing the 2.2uf to 1uf moves the mid suck up a little bit in the frequency that it is sucking to ground. we want to eliminate the low impedance path of 80hz to ground. without adding a lot more parts to this rc lowpass filter, it is probably best to do it like i say adding resistance to those caps. the worst that can happen is it will also be a little more distorted and bright but you will get your bass back and I think that is more important.

I find changing C11 to 10uF does some wonderful thickening/adding low end. I double C7/C8 too but eatyourguitar's method works right too, RC networks and all that.