The humble Proco Rat - a staple of distortion throughout the 80s, and then later rediscovered by people that couldn't afford expensive pedals or just liked the sound. By the way, I refuse to acknowledge the Rat as a fuzz pedal. Others may, but not me...
Excellent analysis on Electrosmash if you have somehow missed it - link here
The layout could be smaller, but I like a bit of room on the board, and it's still only 21 wide.
PROCO RAT WITH MODS - VERO LAYOUT
This modded Rat has switching diodes and an adjustable highpass mod using trimmers. The straight Ruetz-style switch can be a bit much for some people, so the option to dial it in via trimmers and leave it seems like a reasonable idea.
The switching allows for a few diode combinations or just leave off the LEDs for an open setting.
Same again, but without the trimmers.
I made the RAT today, using the version with the trimpots. I'm not sure how I'm supposed to adjust those pots, so if anyone has a hint, I would gladly receive it.
ReplyDeleteFor the sake of experimentation, I used a socket for the transistor, for the germanium diodes and for the LEDs. I'll be trying different sized and different coloured LEDs to listen to what difference this makes (probably not much difference, but it's a bit of fun).
I confirm that the circuit works - now to add a 3PDT switch (and re-test), and then box it!
Hello - normally you would set the trimmers to the stock values, and adjust by ear from there. Listen for changes to the bass response.
DeleteNote for Builders - there are 24 cuts on the board you need to make. Row 1, Column 5 (under the 47R resistor) is a cut that you might overlook - don't!
ReplyDeleteAlso the board is pretty crowded in the top left, so I relocated my Ground from Row 2, Column 1 to the other end of Row 2.
I had to bend all the pins on my Trimpots to get them to fit, especially the 1K pot. I left the trimpots until last, so if you solder them early, YMMV.
Flipping the orientation of the 100k will give more room if needed on the top left. If anywhere will be crowded, I thought it would be the bottom right with the LEDs. That’s less room than I would normally leave for them.
DeleteI use the blue and white plastic trimmers, the larger metal ones will need a bend.