1V per octave for WP20?

[j.frad]

Hi every one, I'm all new to the world of synths and to this forum (been building guitar effects for a while though) and I'm planning on building a WP20.

I know there's no longer an official support for this machine so I'm turning to you guys to find out if the VCO is already 1V/octave or is moddable for it.
My plan is to recycle an old electronic organ to get two keyboards and control one or two WP20s
Thanks a lot for any help!
j.frad

[dnny]

j.frad
i don't know the answer to your question but lets hope that it will get answered - there are some of us that have build the WP20

[j.frad]

thanks for the welcome!
I hope so, the schematics of the VCOs are pretty different though...
On the minisynth the 1V/oct is done around the base of the Q1 and Q2 transistors, it's juste adding a trim and a resistor to ground.
Problem:I have no idea what those transistors do and I really have no clue if there is a similar part on the WP20 VCOs.

I don't have the appropriate knowledge about oscillators...

[ladislaobiro]

[j.frad]

And it looks great! I guess I'll have to built a Minisynth too then! Well that's a good excuse at least...
I could still use the WP20 with a guitar trigger.

My electronic organ is almost fully working, but some keys give no sound and I haven't been able to find the bug, I'd be sad to take it apart for the keyboards and loose the sounds of it and the polyphony.
It's got a nice beat machine in it too, but having 4 of the C keys not working is a handicap!

[autoprod]

I've built the WP20, and thought of adding fine tuning to it, postponed to some future date at current, but still, as it is, I've gotten it to play almost in tune across, well, two octaves at most.

This was done by
- Switching modulation to "manual"
- Switching "controls" - or whatever you label that center knob - to "A.D."
- Tweaking the two of them, along with "VCA sensitivity" until it fit some scale or other


Though I was able to play melody-like fragments, I was left with a very thin sound. What I will be doing is add an external power supply, because the 9V batteries left me with an hour of playtime before the synth drifted out of tune again and would skip triggering every now and then.

I used a Waldorf Pulse (+) to control it. Can't say I found much difference in reliability by alternating between V/oct and Hz/oct settings. (Each needs it's own tuning, though.)

Others might have had better results. I've started to think that this synth was perhaps ment to imitate bird calls, limited to the duck-familly only. (Or, with the LFO nearing maximum, to scare off kids, cats, roadies and sound techs.)

Best of luck, though.

[j.frad]

thanks for sharing your experience! I'll build it any time soon and see what I can do with it...