# Fat Rat



## hamerfan (Jul 14, 2022)

My next build shall be a Rat clone. This could be the Muroidea Distortion. While i watched different Rat versions on youtube i realized that the Fat switch really played great with a Strat. I looked everywhere for a schematic, but no avail. Can anyone help me?


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## Feral Feline (Jul 21, 2022)

I went with G Tranter's bass mod for the Rat, which Marcus copied as well:








						ProCo Rat Bass Mod
					

Everyone loves a big fat filthy bass guitar sound, and a lot of bass players use the Rat to get it. I love the Rat, it’s one of my favourite guitar pedals, but the trouble for bass players is…




					marcuseffects.wordpress.com
				




There's two other ways Tranter showed to switch it up, but I went with the same way Marcus did.

I haven't tried the Reutz mod, but from everything I've read/demos I've heard I decided Tranter's mod was the way to go. 
Sounded great with my Bass-Bass.


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## Feral Feline (Jul 21, 2022)

Yeah, I should've mentioned in my earlier post that I've seen components and circuit discussed, but never an actual schematic. 

I did not mean to imply that anything in my previous post had anything to do with the Fat Rat circuit itself, just things to consider when fattening up a Rat.


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## BuddytheReow (Jul 21, 2022)

So this is where I am with my Pandora...
					

I've read a few things here and there about ways of adding some beef to the Pandora circuit.  I am surprised at how much I like this pedal but have always felt it lacked some grunt in the low end. So with my latest version I have increased C13 to 470nF (from 100nF) to let some more beefy...




					forum.pedalpcb.com
				




It's a simple mod I think. You'll just need to whip up a small daughter board.


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## hamerfan (Jul 22, 2022)

I think i try the 6.8 uF with the original 4.7uF in parallel, if not enough i go with the higher side of the G Tranter mod (560 Ohm and 4.7 uF in parallel).


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## ICTRock (Jul 22, 2022)

hamerfan said:


> I think i try the 6.8 uF with the original 4.7uF in parallel, if not enough i go with the lower side of the G Tranter mod (560 Ohm and 4.7 uF in parallel).


it goes in parallel with the 2u2 ... I suggest looking at an rc filter calculator to see what it does that section of the 2nd order filter


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## HamishR (Jul 22, 2022)

In case anyone is interested and likes Vero - I drew this up recently. It's a Proco Rate with added Bass pot with Chuck's guidance. I haven't built this articular layout but it should work - I have built this circuit and it works well.


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## hamerfan (Jul 23, 2022)

ICTRock said:


> it goes in parallel with the 2u2 ... I suggest looking at an rc filter calculator to see what it does that section of the 2nd order filter


You are right. Its the higher RC network that should come down from 1526 Hz to about 376 Hz.






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Pro Co Rat Schematic, Power Supply Stage, Clipper Amplifier, Voltage Gain, Low/High Pass Filtering, LM308 Op-Amp Selection, Diode Clipping, Tone Control, Output Stage, Pro Co Rat Frequency Response, Resources




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