ilovefuzz.com

I picked up a cheap Yamaha PSS-120 32-key "synth" at a local 2nd hand store the other day. Perfect condition and cheesy as hell... I love it. The only jack on the thing is the 9v-12v power jack so I just added an output jack and a master volume pot. The speaker is still in there but currently not wired in.

The other thing I wanted to do with this was build in some sort of basic fuzz circuit. So, any basic circuits you'd recommend for this? I've never worked with a fuzz circuit so I don't know what a good one might be to throw in here. If it helps at all I already have a load of IN4004 diodes from previous projects... not that the circuit needs to be based around that... just thought I'd throw that out there. Any other simple circuits that would go well with something like this?

Thanks!

If you don't have much room to work with in there, Bazz Fuss is nice an tiny. I have no idea how good or bad it sounds with something like that Yamaha, but since it's only about 6 components, it can't hurt to try. I was thinking of adding one to an old Radio Shack keyboard toy that my daughter took from the inlaws house over xmas. She likes turning knobs and making noises, so even if it sounds terrible, she won't care.

Right on, I do have a bunch of room in there so size of the circuit shouldn't be an issue.

Alright, so this is going to turn into my "help me do this" thread. I should rename this thread the "I'm not as big of an idiot as this thread will make me sound like I am... but I need help". There is nearly no literature online besides a basic manual (no schematics) online but it's ridiculously basic inside. So, first issue (also edited into the 1st post) I was having issues with running the output jack I installed with the speaker disconnected, played around with a few different options for awhile and ended up just running the speaker wires (amplified signal) directly to the jack. This works fine but the output signal is way too high. Rest of the details are in the 1st post.

bongoben wrote: When I have the tiny speaker in the keyboard wired up the output jack works perfectly. I tried unsoldering the speaker wires and I lost about 98% of the volume through the output jack. It's there but it's super faint. Is there anyway I can disable the little speaker in there or does it have to stay wired in to complete some sort of circuit.

That's a bit odd, but I guess if you use a low ohm resistor, 4R or 8R it would work with no speaker. You could also add a switch in there for speaker on off by just switching the load between either the speaker or the resistor.

Well, I decided to just run the speaker wires directly to the jack so there is currently no internal speaker but for the time being that should work. I also added a 10K pot to act as a volume as the straight signal from the speaker wires is pretty hot (from the amp) so the pot can help control that a bit until I pick up the necessary parts to do this the right way. Now, onto figuring out what effects circuits I want to build into this thing.

I love keyboards. I love fuzz. my biggest problem using them together is a the super crazy huge amounts of compression and limiting that can result. good if you want more attack but bad if you get bored with lead sounds. I don't even bother with running keyboards into a fuzz face since the impedance mismatch makes the fuzz clean up to mostly no fuzz. I think a fuzz factory would be interesting if you can fit 5 knobs and source the germanium transistor you need. any 3 transistor fuzz would be good. maybe a tone bender? the bass fuzz that was suggested is a very simple one transistor fuzz that you can make with the diodes you already have. you can wire the bass fuzz point to point without a PCB. it should even work with that crazy speaker amp driving it no problem. if it does not work than you have not wasted any money on the bass fuzz. $0.05 in parts maybe.

I may pick up the parts to try a fuzz factory circuit but in the mean time where are the schematics for this Bass Fuzz (Bazz Fuss?) that was mentioned?

Well, I have a Tonebender MKiii clone coming in trade so I'm going to see what that pedal sounds like with the keyboard and if it works I may just rehouse the pedal into the keyboard.