Casio PT-100

[iqoruvuc]

Can't find any info on this one so thought I would start a thread.

I took the back off quickly and and probed for a few minutes and found some really nice distortions which can all be controlled by pots.  The presets are very similar (if not the same) to other early Casio's like the MT-60; clean sounding and slightly warm.  The distortions are excellent and affect the presets and/or the rhythms, and there is also a multi-turn timmer for the pitch I am hoping will lend itself to manipulation.

I will post more if I find anything else interesting.  I doubt there will be glitches or anything like that, but I am fond of it already 

[Orangery]

I've got one of these machines... one sold on ebay (circuit bent) for £100 plus... didn't look anything great though. 

[iqoruvuc]

Hi - after months of collecting dust I finally finished my PT-100!  All the bends basically cause distortion - each to a different section - kickdrum, rhythm, keyboard and chords - all woud be pretty boring if it wasn't for how good the chords sound.  Also if you tweak the pot that controls the distortion for the rhythm whilst playing chords - the chords turn into a fat square wave - you can mix this sound with the chords and also mix in the distortion for the chords on top of it.

I am going to buy another one and just add this mod and perhaps a more precise pot.  Have a listen and see what you think: http://www.supload.com/listen?s=5OIPF99JGDI8

In this clip it's the normal chord sound, then the square wave base sound creeps in, and then the distortion.  The volume shoots up with introduction of the distortion so watch ya speakers.  Buy one and bend it  - you wont be dissappointed!

[AttDestroyers]

i'm excited, I'll be bending mine this weekend.

[iqoruvuc]

Great stuff!  I am sure there is more to be done then what I did, but if you look for a cluster of resistors around the middle of the circuit board that's were most of the fun is.  I'm thinking of doing this mod again on another PT-100 but only adding the mods for the chord distortion, rhythm (which also turns the chords into a fat square wave) and I am going to attempt to build a low pass filter.

[theshame]

I bent one of these not too long ago. I just want to add that a voltage drop produces some really interesting results. Use a pot between the batteries and the board, and up to around 200 ohms resistance will give you pitch drops, arpeggiated notes, and distortion.

[AttDestroyers]

I also thought the voltage drop was the most interesting bend on this keyboard. Although, I was very disappointed with it compared to my PT-1. Maybe I just need to add some caps in some of the right places.

[jamiewoody]

i may be scoring one of these soon.

i have a general question about the distortion, power crash, etc...are these universal, in most casio keyboards? i have the illustration of the sa-x keyboards mods, is this keyboard similar is where these are found?

[noystoise]

in short, no. the pt-100 and the sa series are totally different keyboards. from what i remember, the pt-100 distortion mods consist of shorting resistors that feed 6 digital audio signals to the amplifier section of the board. replacing the resistors with pots will give you variable gain for the different drum sounds and accompaniment, and mixing the two "lead" channels in different ways will give you some crazy new timbres. i cant remember but i think the sa series keyboards' amplifier section is much simpler. i wish i still had my bent pt-100
heres a video if you want to check it out circuit bent casio pt-100 keyboard
also check out the tablehooters site for tons of info on a lot of great keyboards.