[kind of] OT: WP20 by R.J.Wilson

[ladislaobiro]

Hello everybody,
I just finished my first DIY synth: the WP20, an old synth project (back in the 80's) from Ray Wilson...
I'm so happy with the result that I wanted to share a picture with you DIY synth builders.
Here's a picture, bye...
ladislao

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[elektro80]

HEY! It looks great! Those knobs look like those early 80s Roland rack gear knobbies?

[seraph]

congratulazioni how big is that box

[ladislaobiro]

[ladislaobiro]

here's a complete mini-set of pictures of my project (if it would be too heavy for this forum, please remove the picture and forgive me )...
ladislao

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[mosc]

Nice looking synth... Good job.

[ladislaobiro]

thanks mosc... really thank you
ladislao

[autoprod]

It is a nice design, Lorenzo.

Big thanks for the additional material you added to the WP20 recipee, also. (I had to build one, while waiting for the Sound Lab PCBs. Your new drawings convinced me it was doable. And it was.)


Two questions - perhaps answered elsewhere, but I couldn't find it - (Answering any of these is entirely optional).

1. What's the strength of the Resistor before the (optional) LED?
2. How is the repeat-function ment to work? Mine kicks in now and then, sending a second trigger signal, but turning it on also looses some over-all pitch. So. A bad cap in mine, perhaps?

I also seem to have quite a leak from the LFO to the outsignal. It can be heard, tapping away, when the oscilators are quiet. Also, The VCO leaks through when it's volume is set to zero.

Ah, well. Sorry. It's been a long night.


And thanks to all of you who let the WP20 survive the '80s.

[ladislaobiro]

[Pehr]

Is it possible to mod the WP-20 so it runs on +/- 9 V instead of +9/+18 V?

[dnny]

[Pehr]

yes I know, but I wonder if its possible to run on the same power supply as the SL I'm going to build...

[dnny]

sorry i did´t understand the question in the first place

hmm.. maybe someone knows better but it seems to me that only the noise source is using the 18V all other circuits run on +9V so maybe if you replace the noise source for Ray's "Pink Enough For Me" Noise Generator and you get the sort of pink noise as bonus.


daniel

[autoprod]

Lorenzo -
Thanks for the input. All information is useful, at this level.

18V?
Blast. I thought it was regular +/- 9V. I hereby declare interest in the above predicament. Mine eats batteries, making it hard(er) to keep in tune. Not to mention the AR loosing sustain (Going instead for an occasional early decay) after an hour of play. I could do well with a power supply, and have started building one, albeit it might seem I didn't do my homework prior to buying parts.

[j.frad]

I think you could use a dual -9/+9 Volts if you separate the transformers ground and the ouputs ground, then you can wire the -9V as ground, 0V as +9V ,and +9V as +18V.
Please tell me if I'm wrong!

[toppobrillo]

all you need is a regular [no need for a CT] power transformer rated at around 22-25 VAC, rectify and regulate that with a 7818, then regulate that with a 7809. they are really cheap. oh but yeah, -9 and +9 in series is obviously 18 from -9, just like batteries

[j.frad]

glad I wasn't wrong! sometimes I just wonder...
your idea does sound better though!

[MickMad]

Lorenzo!
Proprio a te cercavo!!!
Ho visto sul sito del wp20 che c'era un lorenzo che ne aveva fatto uno, ma non pensavo fossi un italiano!!

Visto che sono italiano, parlerò italiano con te:
prima di tutto, complimenti! Hai fatto un ottimo lavoro, e mi hai "copiato" pure un idea (infatti io non sapendo come mettere un gate in al wp20, prima di iniziare a costruirlo ho visto se era possibile metterci anche un theremin OTTICO come terza forma d'onda)...
ora i fatti:
chiedo a te che "sai la mia lingua" se va bene quello che voglio fare io: voglio mettere uno switch spdt affianco a quello della selezione forma d'onda collegando il polo del pulsante da attaccare al punto R al polo centrale del secondo pulsante...infine collegare il punto R a uno dei due poli laterali e attaccare il collegamento da saldare sull HOT del jack di output del theremin (vedi questo sito: http://www.oldtemecula.com/theremin/rs-opticaltheremin/rs-opticaltheremin.htm
) all'altro polo del pulsante, mentre la terra dell output del theremin la collego al polo centrale dello switch di accensione del synth (quello dove si attaccano anche i fili delle batterie)... poi volevo chiederti: come hai fatto a mettere il gate in?? perchè vorrei creare un audio to gate converter (http://www.musicfromouterspace.com/analogsynth/signaltogate.html)...solo che non so sia come fare il gate in, sia non capisco molto lo schema del converter...se mi potresti dare una mano...te ne sarei grato..

[seraph]

ragazzi
se volete parlare in italiano va benissimo ma forse converrebbe passare ai PM (private messages) visto che questo e' un forum in inglese. che ne dite? buon lavoro a tutti e due

[MickMad]

che posso dire...
SORRY!