Another Highly Modified Rat

[appliancide]

I built this using ideas from the Beavis Audio FKR and a couple of Jack Orman's articles. It is a beast! I love it.

The signal splits at the input impedance resistor and goes through two sides of a dual opamp (the UA747...because I have them) both set up (sort of) like the FKR.
The blue side has a filter almost identical to a stock Rat, while the black side has a high pass filter that I got from one of Jack Orman's articles (from whom I also got the idea for separate bass and treble gain paths).

Starting from the bottom: The white knob on the left mixes the two channels together. I used a 500k log, but it could probably be smaller (maybe 250k?). The other white knob is the volume. The on-off-on switches above the white knobs select led, ge transistor, or no overdrive for each channel.
The blue and black knobs are distortion, lube and filter.
The two banks of six spdt switches allow symmetrical or asymmetrical clipping for each side. The diodes each have their own switch instead of being wired in pairs. The bottom two sets are ge and si. The top set are si + tv rectfiers on the blue side and ge +si on the black side.
Finally, the two on-off-on switches on the top are symmetrical leds or two zeners in series. I think I will probably take one zener from each side as the audio results are not as interesting as the scope predicted they would be.

I can be a little more thorough if anyone is interested.

To do: Order some blue and black switch covers, label knobs (maybe), remove a couple zeners, learn how to take better pictures, and secure the boards a little better.


Close-up of the clipping board.



Thanks to the entire DIY community for the continued evolution of this great pedal!

[rousejeremy]

Oh my god.

[thereverend]

it needs more knobs and switches!

[ppatchmods]

those look like spark plugs...any sound clips?

[appliancide]

I will try to get my friend to play some clips for me. My playing is not demo-worthy.  Plus, with one person playing and the other tweaking the knobs, the range of the pedal will come through.

I forgot to mention that a lot of the parts in this were rescued from my school's electronics recycling area. I did not seek out tv repair parts, but I'll be darned if won't try to use them!

[newfish]

!

That's immense!  Sound clips are a must!

Well done on your 'Hedgehog' enclosure.

[fuzzo]

What monster

[Belt]

This is what it's all about!

As long as you make a map legend for the switches / knobs

[valdiorn]

it needs more knobs and switches!

No, it needs more cowbell!

Great work, post a clip if possible.

[jacobyjd]

That's no moon...

[ayayay!]

That's no moon...