tube synth diy

I'm building this one that you can find here:
http://www.cgs.synth.net/tube/noise.html
And i am thinking about adding pots, one on 2d21 pin6, and/or another
one on the 12ax7 pin2, did some one tryed this?is it a waste of time
and money? does anybody have some ideas excepted vactrol on pin7...
thank you

>I'm building this one that you can find here:
>http://www.cgs.synth.net/tube/noise.html
>And i am thinking about adding pots, one on 2d21 pin6, and/or another
>one on the 12ax7 pin2, did some one tryed this?is it a waste of time
>and money? does anybody have some ideas excepted vactrol on pin7...
>thank you

Waste of time and money. I expect all you would achieve is a volume control
in both cases, with the addend chance of cooking the 2D21.
Perhaps a pot between a positive voltage and earth connected to pin 5 of the
2D21 may have an effect, though what I don't know. Perhaps a 1M pot in
series with a 1 1M resistor to the power rail, amd make sure you use a pot
rated for the voltage!
Another thing that may be worth experimenting with would be to replace or
augment the fixed magnet with an electomagnet, as moving the magnet does
have a noticable effect.

Ken
_______________________________________________________________________
Ken Stone sasami@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

One obiously awesome thing to do would be to make the magnet rotate around the tube, closely... 

Btw, has anyone tested using an electromagnet for this?

>One obiously awesome thing to do would be to make the magnet rotate
>around the tube, closely...

The first thing to work out is how the sound responds to your magnet. Shape
and strength of the magnet have an effect. I think I recall that rotating
the magnet on the spot so the field is moving around has an effect. Moving
the magnet right around the whole tube may give you more dead spots than you
want. This is one of those cases where the only way to work out what you
need is to try it. You can see the magnet I settled on for the prototype. It
holds itself in that position simply via magnetism. I think it came out of a
CDROM lens assembly.

>Btw i have a drawing for how to do it in my head, looks rather old
>school sci-fi-ish...

Best kind! I'm still wanting to built a super-retro synth. I have a number
of motors with feedback coils on them for tone generation.

Ken
_______________________________________________________________________
Ken Stone sasami@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

>Btw, has anyone tested using an electromagnet for this?
>it'd be interesting to see what effect it has...

Not yet!

Ken
_______________________________________________________________________
Ken Stone sasami@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

i am still working on the random noise generator,

i want to do 2 modifications: first, i'd like to have 2 outputs, and the
second would be to add a pot on the 2d21 anode like on the Thyratron
VCO...

you can look at the schematics and tell me if i am not wrong... i added
it in the photo section that is not used at all, it could be cool to add
pics of your diy synths and drawings of your schematics...

but i wasn't here for it but for help...

so let me know what you think of it...

thank you

Jon

--- In tubesynthdiy@yahoogroups.com, sasami@... wrote:
>
> >Btw, has anyone tested using an electromagnet for this?
> >it'd be interesting to see what effect it has...
>
> Not yet!
>
> Ken
>
_______________________________________________________________________
> Ken Stone sasami@...
> Modular Synth PCBs for sale <http://www.cgs.synth.net/>
> Australian Miniature Horses & Ponies
<http://www.blaze.net.au/~sasami/>
>

>
> i am still working on the random noise generator,
>
> i want to do 2 modifications: first, i'd like to have 2 outputs, and the
> second would be to add a pot on the 2d21 anode like on the Thyratron
> VCO...
>

I wonder if the pot on the thyratron will just reduce the output level
- as Ken wrote- "The circuit has been tested on voltages between 150V
and 200V, with the output level dropping noticeably on the lower
voltages."
What about the 1M resistor feeding back into pin1 of the 2D21, maybe
replace it with a 500K resistor and 1M pot in series....just an idea.

> you can look at the schematics and tell me if i am not wrong... i added
> it in the photo section that is not used at all, it could be cool to add
> pics of your diy synths and drawings of your schematics...
>

good idea, i'd love to see what people are building, or more circuit
ideas, please share.

Andrew

Thank you Andrew for your suggestion, that was what i thought first,
but a little different... look at the schematic.
When i say a "tune control" i mean a kind of "pitch" or "randomness
selector" as they called it...
Secondly, What do you think about the best way to add a second output?
my problem is how will i be abble to plug or unplug one of the two
output without any variation on the outpu level still plugged.
thank you
Jon
I will add some of the books i told with 50's/60's circuits


--- In tubesynthdiy@yahoogroups.com, "bbluthang" <jumpswine@...>
wrote:

>
>
> >
> > i am still working on the random noise generator,
> >
> > i want to do 2 modifications: first, i'd like to have 2 outputs,

and the

> > second would be to add a pot on the 2d21 anode like on the

Thyratron

> > VCO...
> >
>
> I wonder if the pot on the thyratron will just reduce the output

level

> - as Ken wrote- "The circuit has been tested on voltages between

150V

> and 200V, with the output level dropping noticeably on the lower
> voltages."
> What about the 1M resistor feeding back into pin1 of the 2D21, maybe
> replace it with a 500K resistor and 1M pot in series....just an

idea.

>
>
>
>
>
> > you can look at the schematics and tell me if i am not wrong... i

added

> > it in the photo section that is not used at all, it could be cool

to add

> > pics of your diy synths and drawings of your schematics...
> >
>
> good idea, i'd love to see what people are building, or more circuit
> ideas, please share.
>
> Andrew
>