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diegodonatelli
Joined: Feb 13, 2009
Posts: 2
Location: southwest germany
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 Posted: Fri Feb 13, 2009 12:41 am Post subject:
First Build: Tube VCO oscillates all the time?
Subject description: VCO built is always on.... |
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Hi everybody , I m new to this forum.
I build some tube amps in the past and want to build an modular Synth.
So i though it would be good idea to start right away with the tube modules Ken Stones has on his website.
I built the VCO with the thyratron tube and it works and sounds good, but...
It works all the time, i mean whenever the power is on, the thing oscillates.
The sound is tuneable and i can modulate the sound with e.g. the output of my zacky wany weird microsynth.
Now my questions:
is this normal, are vcos in modulars always on and are only controlled by a ADSR and a VCA?
My build has one change to the schematic on Ken Stones website:
In the first tube stage the cathode of the ecc81 is connected to a -150v supply but there is no -150v port in the schematic of the powersupplies of Kens page.
So I connected it to ground, thats what you usually do in tube amp gain stages. wrong?
any help is appreciated, thanks in advance! |
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Funky40
Joined: Sep 24, 2005
Posts: 875
Location: Swiss
Audio files: 1
G2 patch files: 5
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Posted: Fri Feb 13, 2009 3:18 am Post subject:
Re: First Build: Tube VCO oscillates all the time?
Subject description: VCO built is always on.... |
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| diegodonatelli wrote: |
Now my questions:
is this normal, are vcos in modulars always on and are only controlled by a ADSR and a VCA?
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Yes
oh, and  at electro-music |
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andrewF
Joined: Dec 29, 2006
Posts: 1176
Location: australia
Audio files: 4
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Posted: Fri Feb 13, 2009 5:13 am Post subject:
Re: First Build: Tube VCO oscillates all the time?
Subject description: VCO built is always on.... |
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| Funky40 wrote: | | diegodonatelli wrote: |
Now my questions:
is this normal, are vcos in modulars always on and are only controlled by a ADSR and a VCA?
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Yes
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yes VCOs are always on but are not controlled by VCAs.
usually with a VCO you can control the pitch/frequency, and sometimes the waveshape.
To turn the sound on&off you need a VCA
for the standard attack/sustain/decay/release you need an ADSR to control the VCA.
this is the 'normal' way of doing things, doesn't mean you have to, feel free to find your own techniques.
Interesting entrance into synths, starting with the tube VCO...well done!!
whats next?
BTW - to get -150V just reverse all the diodes and the caps on the power supply schematic. there is a version of it in this CGS forum, here-
http://electro-music.com/forum/topic-26842.html |
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diegodonatelli
Joined: Feb 13, 2009
Posts: 2
Location: southwest germany
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| Posted: Fri Feb 13, 2009 1:46 pm Post subject:
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Thank you for your Welcome funky40,
Thank you andrewF,
the link to the power supply thread is very helpful.
Now that i know that i need a VCA to control the VCO, the next module is clear: the CGS tube VCA, i happen to have the EF86 tube lying around from a preamp experiment so this is the next step, and i m waiting for a defective Yamaha keyboard I shot at ebay to be my keyboard controller
I' ll keep You informed about me proceedings,
nice helpful forum you guys have here!
_________________
www.bernardodonatelli.com |
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