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tube projects

tube projects

2004-09-06 by charlesosthelder

Hey Ken!

Having given up trying to make a +-15vdc supply work with the beam
mod project, I've decided to build a high voltage unit. This will
include a pentode preamp and 6BN6 clipper as well. I found a perfect
transformer (270V secondary, center tapped and a center-tapped 6V
filament)in my junk box, too!

I have a question about the clipper circuit, however. Why does the
schematic list 12 volts for the filament with the 18 ohm resistor?
Everything else seems pretty straight forward.

Dave Wright of Carrion Sound (people - check out his CD, Not
Breathing, for a real treat! http://www.carrionsound.com or
http://www.notbreathing.com ) said in an email that you use the beam
modultor without inputs! I *want* this thing! Your input
(modulated or not...) would be greatly appreciated!

Chub

Re: tube projects

2004-09-06 by sasami@hotkey.net.au

>I have a question about the clipper circuit, however. Why does the
>schematic list 12 volts for the filament with the 18 ohm resistor?
>Everything else seems pretty straight forward.

That is because in Eric's original article, he allowed for surplus 4BN6 and
3BN6 to plug into the same socket without modification. If you have the
6BN6, wire it to 6 volts as you would usually. Personally I don't like the
resistor idea and instead prefer to use two 3BN6 in series across the
regular 6V supply, as I did buy the surplus tubes.

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

Re: tube projects

2004-09-08 by charlesosthelder

Hello again, Ken!

Do the beam modulator and soft clipper circuits have gain?

Chub

Re: tube projects

2004-09-09 by david wright

hey guys - the clipper has no gain, and needs some gain
before it works too well. the beam modulator does not
boost gain i do not belive. i can test tonight

dave wright

----- Original Message -----
Show quoted textHide quoted text
From: sasami@...
To: cgs_synth@yahoogroups.com
Sent: Wednesday, September 08, 2004 4:14 PM
Subject: Re: [cgs_synth] Re: tube projects


>Hello again, Ken!
>
>Do the beam modulator and soft clipper circuits have gain?
>
>Chub

Um... I don't remember.... That section of my synth isn't connected up at
the moment...
Ken
_______________________________________________________________________
Ken Stone sasami@... or sasami@...
Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>



See the following URLS for the CGS Modular Synth home page:
Main: http://www.cgs.synth.net/
Secondary: http://otherunicorn.0catch.com/synth/


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Re: tube projects

2004-09-09 by charlesosthelder

So I should probably build the pentode preamp to drive these
devices? No problem. A tube VCA at the out would be a nice
addition as well...

Chub

--- In cgs_synth@yahoogroups.com, "david wright" <bastardita@h...>
wrote:
Show quoted textHide quoted text
> hey guys - the clipper has no gain, and needs some gain
> before it works too well. the beam modulator does not
> boost gain i do not belive. i can test tonight
>
> dave wright
>
> ----- Original Message -----
> From: sasami@h...
> To: cgs_synth@yahoogroups.com
> Sent: Wednesday, September 08, 2004 4:14 PM
> Subject: Re: [cgs_synth] Re: tube projects
>
>
> >Hello again, Ken!
> >
> >Do the beam modulator and soft clipper circuits have gain?
> >
> >Chub
>
> Um... I don't remember.... That section of my synth isn't
connected up at
> the moment...
> Ken
>
_____________________________________________________________________
__
> Ken Stone sasami@h... or sasami@c...
> Modular Synth PCBs for sale
<http://www.blaze.net.au/~sasami/synth/>
> Australian Miniature Horses & Ponies
<http://www.blaze.net.au/~sasami/>
>
>
>
> See the following URLS for the CGS Modular Synth home page:
> Main: http://www.cgs.synth.net/
> Secondary: http://otherunicorn.0catch.com/synth/
>
>
> Yahoo! Groups Sponsor
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> Yahoo! Groups Links
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>
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> [Non-text portions of this message have been removed]

Re: tube projects

2004-09-23 by charlesosthelder

Finally - power and light!

The nearly finished pentode preamp/soft clipper/beam modulator was
fired up and tested last night. The beam modulator works very well.
With two audio freq CV inputs and an audio grid input, it produces
two very nice sideband outputs.

The clipper does indeed require a preamp, but it sounds great!
Unfortunately, the screen voltage pot fried after a few minutes!
Apparently, a 1/2 watt, 1M is too puny for the 200 VDC being tapped
from the plate supply. My grandson was very impressed with my calm
reaction to fire, too! In my little world, it's not fun until
something smokes. Obviously, a limiting resistor is necessary to
keep the current low enough through the screen voltage pot. That'll
be installed and tested tonight.

Most of the part for this project were straight from the junk box.
The enclosure and chassis started life as a RCA tube sine
oscillator. I made a new front panel for it and added a couple of
holes. This device also provided the transformer and pilot light
assembly. I bought some 6AU6 and 6BN6 tubes from Antique Electronic
Supply and scrounged everything else from my parts bins. Total
investment - under $10 (it would have been less but I bought two of
each tube, just in case). Total fun factor - way high!

I'll post a photo or two in the near future. Thanks to Eric Barbour,
Ken Stone, and Dave Wright for your input!

Chub- fun is my business and I've got the scar tissue to prove it!

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