Yamaha PSS series keyboards.

[computer at sea]

The PSS-11 has only a couple of bends, but they are fantastic on some of the voices.  It produces probably two of my all time favorite stable and musical bends.  I bent mine about a year ago just doing straight point-to-point stuff and found maybe four things, but I haven't been back in to try any of the more advanced techniques. 

My only issue with this keyboard is that there isn't an LED to indicate when the power is on, and you can't tell by a quick glance since it uses that big round knob instead of a slider switch.  I ended up builidng an LED into mine without too much hassle.

I'll crack it open this evening and post the points I found.  Unfortunately, as I'm currently without camera I'll have to give you a verbal description.

[punchingsandwiches]

Hey there, recently got into circuit bending and thought I'd try it out on my old PSS-80 I've had since it seemed as big as a full sized keyboard. Anyway, I have found some interesting glitches and loops but have yet to find anything on the board that I can change the pitch with, I've tried wetting my fingers and shorting out a few resistors near IC's but no luck. If anyone could help.

Also I am having trouble working out how most of it is connected, the PCB trace seems to be inconsistent and neither the light green or dark green lines and patterns seem to connect the whole board.

Also, also I'm having a hard time finding bends that can be manipulated by pressing keys.

Cheers.

N

[iqoruvuc]

To change the pitch you will have to replace the crystal with a range of crystals with different speeds or else create your own oscillator.  This is the same for all but the cheapest toy keyboards. Some the older semi analogue keyboards can be manipulated by finding points on the circuit board but most cannot. 

You can find details for making your own oscilator on sailmouth's website, though I have never made one myself...would be interested to know if anyone else has?

[punchingsandwiches]

Ok, thanks. Is the oscillator your talking about basically a variable 'crystal' then? Like the relationship between potentiometer and resistor?

[kick52]

Yes, basically.

[computer at sea]

Hey Ne7,

I finally got around to opening up my PS-11.  The really fantastic glitch is a straight jumper between pins 31 and 29 on the big chip.  It doesn't sound like much with the piano setting, but if you fuss around with other sounds there's some really amazing stuff.

[nochtanseenspecht]

i get more and more questions by mail about bending the yamaha pss390
so i want to ask if anyone has question about it, to post them here in the forum,
so that others can take profit/ give answers to

however i don't remember exact details, it has been some time ago that i bended it...
what i remember : it is a multi layer circuitboard, witch makes it very difficult to trace the lines.
so the regular FM dataline cut mod would take a lot of investment if even possible
if ever i open it up, i will take some pictures and post them here

but still one of my favourites, the pss390 4 operator fm keyboardsynth with slider control

[egr]

Hey all, new to the forum.  This topic led me here.  I just finished my first bending project.  A Yamaha PSS-30.  I added two pots that make nice feedbacky squelches on their own and modulate the voices and beats really well.  Also a "distortion/glitch" switch that isn't that useful but sounds good with most voices.

Here's a pic so you can check out my "awsome" paint job 

[Circuitbenders]

That actually looks really professional, nice job. 

[egr]

That actually looks really professional, nice job. 

Much appreciated!

Kudos on the WSB quote in your sig, BTW 

[Circuitbenders]

Kudos on the WSB quote in your sig, BTW 

[egr]

Just completed the data cut mod on a PSS-170 and I wanted to post some additional info:

I didn't have the room (or skill  ) to use them this time but there are at least 7 more points that could be added to this mod on the PSS170.  I believe they control the drum patterns and maybe the sounds as well.  I've recycled a pic from Circuit-Bent to show where they are:

EDIT:  Oops.  Skip the point on the far left.



When I get my camera back I'll post a pic of my new toy.  I did a "SK-1" style patchbay in the speaker specifically to try and unravel just what can be done with the data lines.  To use all the lines you'd definately have to have a breakout box.

Later!

[zoomtheline]

i get more and more questions by mail about bending the yamaha pss390
so i want to ask if anyone has question about it, to post them here in the forum,
so that others can take profit/ give answers to

I got one of these on Sunday and I have already used it in a track (unbent) and was really chuffed with it.
I am even more chuffed to find its the one you have been raving about! ha. I remember reading your post a while ago and thinking I that it would be amazing to get a 390 but the chances are slim as the ones you see in junk shops always seem to be the wrong ones. Not this time though! ha
I really want to bend it but I am scared I will fry it as I don't really know to much about particular bends, I just delve in and try and find stuff that sound interesting. I don't want to ruin it as I know I will definately get use from it unbent aswell.

Are you able to help me?

I have just been given a PSS580 this morning aswell and while it has no synth sliders it has all that the 390 has and it even has Midi!!, could I test stuff out on the 580 and get the same/similar results as the 390?

Are you able to give me any help on the 390/580? you would be helping a very happy dude!

Cheers

[nochtanseenspecht]

congratulations with the pss-390 

i read back from my old post, that i found only 3 chips interesting ;

.
the 25 pins i soldered to the YM7129 , LC3564PL and the XG314BO.
i wanted to finish it quick, so i didn't invest the other ic's somuch as they didn't seem interesting

my other investments i don't remember, but certainly you would find more if you take time.
but on these 3 ic's you will be save i guess. mine always recovered from a crash after powering up again.

i did it patchbay style, with an external box. i found most bents pretty stable, in the sense that you always get the same madness in a certain patch. on the other hand it could be totally unpredictable. in some patches it sounds totally strange, but the sliders still function as usual, in other patches they trigger glitches.
on some of the patchpoints i used to connect an antennae, so it could interfear with digital streams in the area,
like cellphones, bluetooth etc, wich seem to modulate the fm carriers (or something )
very nice. also the display acts realy superb, almost scary sometimes
the sound of this keyboard is also very nice. the stereo can be very wide.
in general i see this board bended as an intergalactic broadcast receiver, at least that's how it sounds 


580 i don't know. just be carefull around the DC inlet area . try to search for datasheets on ic numbers.
if it has the same ic's as the 390, your a lucky basterd with midi !
and dont forget to interconnect them ! and let us hear some mp3..

good luck !

[nochtanseenspecht]

some pictures from inside the pss 390