Stringz n thingz

paulmorison · Joined: Feb 27, 2013 Posts: 32 Location: UK

Hi all
Just wondered if there was anyone who knew if you could mod a Stringz n Thingz Kbd to have a second function of controlling a PAiA 4700

richardc64 · Posted: Sat Apr 30, 2016 11:40 am Post subject:

It could be done. See here http://electro-music.com/forum/post-419130.html#419130

It'd need quite a number of parts, though.

Cfish · Joined: Feb 24, 2016 Posts: 477 Location: Indiana

The easiest way would Probably be to add a reed switch to each key, and creat an independent control system. the top octave system does not give you a lot of other choices.

I have a PAIA OZ Clone with some added mods I built, and a set of PAIA 2720 modules I am restoring. I always wanted a strings n Thingz. They are cool. Best of luck if you decide to give it a try.

paulmorison · Joined: Feb 27, 2013 Posts: 32 Location: UK

Thanks both of you for some great ideas and leads, I will try these, or I might fit a midi to cv converter and use a controller kbd

Cfish · Joined: Feb 24, 2016 Posts: 477 Location: Indiana

You got me thinking. If the strings n things is done like the OZ was, and I'm not sure of that. There is a set of switches to control the gate/trigger out. My OZ is on perf board, so I left these out. There is a chain of capicitors you could remove. Then a set of resistors you could remove. Both are only involved in the gate/ trigger signal. Then reinstall 100 ohm high tolerance resistors back with each one shifted one space over at one end. Then you would need to cut the buss traces between them. This would make a resistor chain between the second set of switches. You could then ad on a basic op amp control circuit, and add back the gate signal with 2 or 3 op amps.

You would definitely want to be sure you understood what you were doing, because it would require quite a bit of board modification. However on an original factory OZ board. It looks like it would be pretty easy to do.

Still not sure if the STrings n Thingz keyboard control section was larger version of the OZ. but I suspect they used the same concept.

i will try to find a schematic for strings n things to be sure.

richardc64 · Posted: Sun May 01, 2016 7:28 am Post subject:

S&T keyboard has a 2nd buss of contacts that produces an on/off +V when any key is pressed. It is used internally to VCA the chorus circuit and is also brought out externally as a Gate Out. Its function could be duplicated with a 37-input OR, most easily constructed with 37 diodes each connected to the note-generating contacts, K1-K37. (The beast already contains 527 1N914s, so 37 more shouldn't be a big deal.) The 2nd buss could then be rewired as a single-buss resistor string controller. http://www.musicfromouterspace.com/forums.html?CATPARTNO=SINGLEBUSSKBRD2007&PROJARG=SINGLEBUSSKEYBOARD2007%2FSINGLEBUSSKEYBOARD2007.php&MAINTAB=SYNTHDIY&SONGID=NONE&VPW=1024&VPH=500
(I can't believe I'm advocating that!)

But the K1-K37 contacts provide on/off for each key. These could be scanned by a 37-input multiplexer, or a priority type of circuit like I suggested earlier.

Cfish · Joined: Feb 24, 2016 Posts: 477 Location: Indiana

if I had an original S and T I'm certain I would not want to put it through the punishment of all that unles it was just a horrific bad build to begin with.

I have Ben trying to find one of these for years. When I find one I don't have the money. When I have the money there isn't one to be found.

richardc64 · Posted: Sun May 01, 2016 9:10 am Post subject:

Cfish · Joined: Feb 24, 2016 Posts: 477 Location: Indiana

That was what I ment Richardc64

My idea would be torture on the poore thing.

Cfish · Joined: Feb 24, 2016 Posts: 477 Location: Indiana

If anyone had a link to good legible s ang t. Schematics I would love to have a closer look. Ones I found werennt very legible

(Werennt) my spell check keeps doing that. I'm now tired of fixing them LOL

richardc64 · Posted: Sun May 01, 2016 10:03 am Post subject:

Stringz-n-Thingz article by Marvin Jones from Radio-Electronics Feb-Mar '79.

http://www.paia.com/talk/viewtopic.php?f=6&t=31

Cfish · Joined: Feb 24, 2016 Posts: 477 Location: Indiana

Thanks Richardc. I printed those off. I do intend to own one before I die.

I finally gave up and did the OZ on perfboard, and built a 3 octave using the same set up as the OZ with more dividers. I had decided a long time ago that the strings n Thingz was way more than I wanted to try on perf. Though it does not look quite as bad as I remembered it.

Grumble · Posted: Tue May 03, 2016 3:09 am Post subject:

I would scan the keys with an Arduino and some demultiplexers, have the Arduino make the trigger and gate signals, and a DAC for the CV.

richardc64 · Posted: Tue May 03, 2016 3:42 pm Post subject:

Cfish · Joined: Feb 24, 2016 Posts: 477 Location: Indiana

paulmorison · Joined: Feb 27, 2013 Posts: 32 Location: UK

Wow, some great and weired ideas to get me thinking
I suppose the easiest thing would be to get the PAiA Road Kbd for the 4700 modular. But:

1. That's too easy, and modding the PAiA and using the Musicfromoutespace idea looks like fun, although may take a few months!
2. Finding a Road Kbd on it's own is about as likely as Donald Trump making a contribution to a Mexican aid fund!

Thank you all though, some things to think about, and if I complete this, Ill post results

Cfish · Joined: Feb 24, 2016 Posts: 477 Location: Indiana

2. Finding a Road Kbd on it's own is about as likely as Donald Trump making a contribution to a Mexican aid fund!

There is one on eBay right now that was set up for computer interface. Kinda pricy. But it's there.

paulmorison · Joined: Feb 27, 2013 Posts: 32 Location: UK

Thanks for that-just bought it, paid way over the odds, but worth it

Cfish · Joined: Feb 24, 2016 Posts: 477 Location: Indiana

Awesome. Glad you got it.