Yamaha PSS-570

Matana Teknik

Hello every one I'm new Very Happy

With great interest i've been reading many articles about circuit bending the last week. Can't even remember how I got on to it but I did. A few years back some one gave me a Yamaha Portasound PSS-570. I wanted to practice but I was to busy with performing as a dj so it disappeared in the bottom of my closet because it has no Midi and I'm creating music with Cubase and some hardware now. Then I stumbled upon the PSS-270 bending tutorial by Kevin Reese. But this involved the YM2413 chip and this PSS has YM3812 chip, which in my opinion is better. After many hours of reading and understanding how this system works I took my PSS apart. Man, the things i discovered in this keyboard are amazing!!! Total self oscillating, reverbs, flangers, envelopes total madness!!! The last couple of days I recorded about 2 hours of raw material but cuttable and very useful for the music that I make (Techno/Tekkno/Acid/Hardcore etc).
This keyboard has some very dark and pounding kickdrums perfect for hardcore and tekkno. But also strange acid lines and total noise.....
I managed to hotwire two connections which add volume,distortion and opens up all other abillities of the chip, I think. Anyway the sound is awesome and is has been running for four days(not continue) now without any heating of the components so I think its ok.
I'm gonna make schematics of this bend because I think its possible to add: a matrix or touch board(there are so many points on the board that can be connected,some even have six options) flick switches for normal/distorted mode and loudness. I think its also possible to at pot meters to some connections but I don't have those yet. Another strange thing that is happening is that when the PSS is in fingered bass mode or single fingerd mode you can play the keyboard an it starts making combination rhythms of its own like fast arpeggio's perfect for acid-tekkno. When you hold a key for a long time it emerges with the bass sound and add's its tone to it which remains in the sound!!! wicked awesome....
Also I discovered that on the touch board(throw away your buttons and sliders you're not gonna need them again) that if you connect let's say decay 4 with cymbal 3 it changes and you can do this all over the board and it will integrate in the sound. I managed to get filter sweeps with envelope that run for 32 bars and more. So I'm gonna make a open touch board so I can easely switch between the different values(i can go from 1 to 5 without going past 2,3 and 4 and I can patch the different functions with each other to create maddness)
Like i said I gonna keep everyone up to date about this bend and I will add some samples in the next few weeks. This keyboard is gonna look brutal. The DenDer YaMaHAAI (HAAI means shark in Dutch)

Matana Teknik

Found this on YouTube

This how my Yamaha sounds now......although the recording quality sucks... i've had a major computer crash which ment i had to restart everything so samples are now soon to follow....

Matana Teknik · Posted: Tue Oct 28, 2008 6:06 pm Post subject:

So after a year it is time to revive this topic.
It's done my Yamaha.....
Posted Image, might have been reduced in size. Click Image to view fullscreen.

So what's in it?

Left panel:
The upper three switches are from left to right for clipping circuit on a build in Mufffuzz effect, true bypass for fuzz effect and a mild distortion switch that also eliminates the drum section.
The three pots are for the stereo chorus mod, which controls depth and intensity. The middle pot is for the fuzzzzz.
The two pedalswitches are connected to some points on the CPU that need a shit shot to create mayhem. The big on/off switch is for total distortion.......
Right panel:
Consists of the patch matrix and dataline interrupters as described on http://circuit-bent.net/pss-270-tutorial.html
The 570 has the 3812 FM opl2 chip so it has a different pinout than the 270. Near the CPU there are 8 resistors, just solder these loose and connect them to the always on momentary switches. So the 8 red buttons are for this mod.
The four black momentary switches are connected to the rhythm section creating new arpeggios and stuff.
At the right you see 2 vertical colums. The 2 upper cinches are connected to two hotspots. The switch above it let you connect them to the four remainig cinches. So it is a little switch matrix.
I'll document this on my own site at www.acidcult.nl I'll also post pictures there of the inside of the PSS570 with all the bend points.
Hope you like it.

Overhere http://www.synthforum.nl/forums/showthread.php?p=1014892#post1014892 you can hear some audio.