Lo-Fi Pedal Mods and Ideas

[ercsguitar]

I've been itching for a pedal that would basically make my rig sound like a busted old transistor radio. So I recently bought a GGG LoFo MoFo board that I'm getting ready to build, but not being content to go with the stock options I'm looking for good mods to add to it. Here are somethings that I've considered.

Switchable Input caps
I think I've seen a couple builds with these. One was on a rotary switch and had 5 or 6 options. I'd probably put mine on a garden variety toggle switch with 2 drastically different options. Of course I can't find those builds now. What I'm looking for with this option is the ability to change the high pass filter to different cut off points.

Clipping
I'd like to add some sort of clipping, maybe something like the Lo-FI Drive. But I'm pretty new to this whole thing, so I'm not even sure what my options are and what results that would get me. I don't know if I should add si or ge diodes, LEDs or what. In the end I'd like it to sound like crackly old vinyl.

Voltage Sag
While I may not build this into the pedal (I've got a Voodoo Lab Pedal Power 2+), it would be interesting to see what happens when a crappy sounding circuit runs on less than optimal voltage. More distortion?

Interference
I've even thought about adding a radio antenna a la the Beavis Junk Fuzz (see http://www.beavisaudio.com/images/jf1.jpg). It would almost certainly have to be switchable because you never know how hot the radio signal might be. This is a real problem in my town with a certain poorly regulated radio station.

In addition to the Lofo Mofo I've also examined the Lofi Drive and R.G. Keen's Low-Fidelity Telephone Noise Pedal. I want to keep this pedal a basic filter, but I'm not opposed to some sort of mild clipping additions. I do want to stay away from atari game noises and bit crushing. I've named it the Lo-Fildelity Radio after all.

[ambulancevoice]

something like this???

the caps in the switching can be what ever you like
they can range from high to low or low to high
the diodes can be anything, 1N4148/914, LEDS, 1N400* Zener or Schottky diode, 1N60 (Germ), 1N34A (Germ)
grab some pairs of random diode and chuck em together
judge by ear
the antenna, i believe only has one connection
if it doesn't work there, try it right at the output (just before the volume pot)
im not sure what sag pot value would be suitable, but just try what you think

[ercsguitar]

Thanks, that's sorta what I'm looking for. I'm beginning to think the antenna idea might be too problematic if I can't take it out of the signal path. I'll take any suggestions for things to do to this pedal.

[sean k]

I don't know if it would work but hooking an antenna to an old radio variable cap and then attach that straight to signal or maybe hook it to a LDR and have it set under a hole in the top of your enclosure. Those old Variable caps used string drive so you could hook a pedal, ala wah, volume etc, and use your foot to control the cap. Maybe you'd have to demodulate the RF... actually I suppose you would...

[ambulancevoice]

spst switch or maybe a typical volume control to blend or turn off the antenna would work

[Processaurus]

http://www.diystompboxes.com/smfforum/index.php?topic=68123.0

[runmikeyrun]

I built one similar to ambulance's.  It was cool but ultimately it was easier to control v 2.0- i used a pot to sweep between two filter values, one with a large cut and one with a small cut.  That way you can dial in just what you want and it gives you the illusion of having more control.  Would you rather have a 6 position drive adjustment or a smooth pot?

[ercsguitar]

Thanks for all your help with this. I really like the antenna idea with a radio pot on it. I've got an old 8-track stereo system with a radio on it I might rip apart and give that a shot. Or maybe I'll hit Goodwill.

I also really like the idea of two filter caps on a pot. What value of pot would you use for something like that?

[railhead]

I've had success with 250k and 100k.