Pack RAT (stock, Turbo, “You Dirty” Rat clipping options)

manfesto

Active member
Not the cleverest idea by any means but not one that I’ve seen before, surprisingly?

Lots of Rat mods use an on-off-on switch to change out Rat clipping diodes, but for some reason seems everyone likes to use the off position to just remove the clipping diodes entirely for op-amp clipping.

Do people actually *like* op-amp clipping??? Like, it’s just *so* harsh and gross to my ears, especially with the low-spec op-amps that Rats use.

Not my thing ¯\_(ツ)_/¯

So I went with a Triad Distortion board which is already 95% of the way there, used an on-off-on switch, put germanium diodes in D1&2 and silicon diodes in D3&4, and strapped antiparallel LEDs between pin 1 of the filter pot and ground so that when the switch is in the “off” position the signal will still get clipped by the LED. This gives “stock” clipping in the top position, “Turbo” clipping in the middle, and “You Dirty Rat” clipping in the bottom position, and it all looks clean!

If you’re gonna do a clipping switch mod on a Rat, the Triad Distortion is an easier starting point than the Muroidea imho. (Probably other mods too, the single line of potentiometers leaves more room for external controls.)

(also, not that it matters since they’re antiparallel, but I installed the germanium diodes backwards. I forget the stripes are backwards on D9s like half the time and it’s *so* annoying.)
 

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mdc

Well-known member
So the signal always runs through the LEDs, but since the other diodes will clip earlier than the LEDs, signal will basically pass through the LEDs relatively unaffected until the Ge/Si are switched out?
 

Chuck D. Bones

Well-known member
The signal runs to the LEDs. If the switch is in either of the ON positions, then diodes with a lower Vf are in parallel with the LEDs. As a result, the LED current approaches zero. With essentially no current in the LEDs, they have no effect on the signal.
 
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