Tube synth diy

Hi all
looks like my first post describing this synth has disappeared
so try again.

finished first rack of a tube modular.
pics in Photos.
I am planning to build a few of each module so designed and etched
circuit boards for the circuits.

Eric Barbour VCO - works fine

Beat Frq VCO - I built an EB VCO and changed the cap around the
thyratron to get the operating range around 20-30kHz. The output goes
into a 6AR8 modulated by two neon oscillators set to run at 25kHz. It
"kinda" works but needs some sorting. Neon oscillators are apparently
quite unstable above 10kHz, which I view as a good thing, at the
moment it seems they only fire at certain settings, maybe too
unstable.....anyway, debugging to do.

Rene's VCF - built two of these, both with sync-able neon LFOs, the
idea being the flashing neons drive the LDRs in the filter circuit and
I get a LFO output too. The neons and LDRs came from some old HP lab
gear, so I figured they should be fine. One is, but the other isn't,
which probably indicates a wiring error. I used 6021 sub-mini tubes
for the triodes and 6AU6 for the pentodes. The 'scope shot is from the
VCF that works, it sounds as nasty as it looks, I like it!

Electronic Peasant VCA/Mixer 2&3. If you have seen this design it is
the one with the 600:600 Ohm transformer on the output. It works
perfectly! I think I might try a few more EP designs

Power supply is +/-140V, but I will increase the output to ~160 or so.
heaters are powered by a switching PSU from a computer, just added a
pot to get 6.3V from it at 20A.
All sockets BNC, today I built an interface panel to send/rec signals
with my other synths. 

cheers
Andrew

Off looking at the pictures now :)  

I'd love to do one as if it had been built back when tubes were usually used
- wood panels, or back-painted perspex, bakelite knobs and so on.

Ken

>Hi all
>looks like my first post describing this synth has disappeared
>so try again.
>
>finished first rack of a tube modular.
>pics in Photos.
>I am planning to build a few of each module so designed and etched
>circuit boards for the circuits.
>
>Eric Barbour VCO - works fine
>
>Beat Frq VCO - I built an EB VCO and changed the cap around the
>thyratron to get the operating range around 20-30kHz. The output goes
>into a 6AR8 modulated by two neon oscillators set to run at 25kHz. It
>"kinda" works but needs some sorting. Neon oscillators are apparently
>quite unstable above 10kHz, which I view as a good thing, at the
>moment it seems they only fire at certain settings, maybe too
>unstable.....anyway, debugging to do.
>
>Rene's VCF - built two of these, both with sync-able neon LFOs, the
>idea being the flashing neons drive the LDRs in the filter circuit and
>I get a LFO output too. The neons and LDRs came from some old HP lab
>gear, so I figured they should be fine. One is, but the other isn't,
>which probably indicates a wiring error. I used 6021 sub-mini tubes
>for the triodes and 6AU6 for the pentodes. The 'scope shot is from the
>VCF that works, it sounds as nasty as it looks, I like it!
>
>Electronic Peasant VCA/Mixer 2&3. If you have seen this design it is
>the one with the 600:600 Ohm transformer on the output. It works
>perfectly! I think I might try a few more EP designs
>
>Power supply is +/-140V, but I will increase the output to ~160 or so.
>heaters are powered by a switching PSU from a computer, just added a
>pot to get 6.3V from it at 20A.
>All sockets BNC, today I built an interface panel to send/rec signals
>with my other synths. 
>
>cheers
>Andrew
>
>
>
>------------------------------------
>
>Yahoo! Groups Links
>
>
>
>
_______________________________________________________________________
Ken Stone   sasami@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

Have a look at the pics I put in 'old gear'
one day I'd like to build synths looking like this....would have to
grow a beard and smoke a pipe whilst playing them.




--- In tubesynthdiy@yahoogroups.com, sasami@... wrote:
>
> Off looking at the pictures now :)  
> 
> I'd love to do one as if it had been built back when tubes were
usually used

> - wood panels, or back-painted perspex, bakelite knobs and so on.
> 
> Ken
> 
> >Hi all
> >looks like my first post describing this synth has disappeared
> >so try again.
> >
> >finished first rack of a tube modular.
> >pics in Photos.
> >I am planning to build a few of each module so designed and etched
> >circuit boards for the circuits.
> >
> >Eric Barbour VCO - works fine
> >
> >Beat Frq VCO - I built an EB VCO and changed the cap around the
> >thyratron to get the operating range around 20-30kHz. The output goes
> >into a 6AR8 modulated by two neon oscillators set to run at 25kHz. It
> >"kinda" works but needs some sorting. Neon oscillators are apparently
> >quite unstable above 10kHz, which I view as a good thing, at the
> >moment it seems they only fire at certain settings, maybe too
> >unstable.....anyway, debugging to do.
> >
> >Rene's VCF - built two of these, both with sync-able neon LFOs, the
> >idea being the flashing neons drive the LDRs in the filter circuit and
> >I get a LFO output too. The neons and LDRs came from some old HP lab
> >gear, so I figured they should be fine. One is, but the other isn't,
> >which probably indicates a wiring error. I used 6021 sub-mini tubes
> >for the triodes and 6AU6 for the pentodes. The 'scope shot is from the
> >VCF that works, it sounds as nasty as it looks, I like it!
> >
> >Electronic Peasant VCA/Mixer 2&3. If you have seen this design it is
> >the one with the 600:600 Ohm transformer on the output. It works
> >perfectly! I think I might try a few more EP designs
> >
> >Power supply is +/-140V, but I will increase the output to ~160 or so.
> >heaters are powered by a switching PSU from a computer, just added a
> >pot to get 6.3V from it at 20A.
> >All sockets BNC, today I built an interface panel to send/rec signals
> >with my other synths. 
> >
> >cheers
> >Andrew
> >
> >
> >
> >------------------------------------
> >
> >Yahoo! Groups Links
> >
> >
> >
> >
> _______________________________________________________________________
> Ken Stone   sasami@...
> Modular Synth PCBs for sale <http://www.cgs.synth.net/>
> Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>
>