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CGS65 Tube VCA

CGS65 Tube VCA

2007-01-18 by bbluthang

I got this module running today. It is VERY good and does some very
interesting things beyond regular VCA duties.

I used a 1AG5 tube, different pinout and some different resistors to
up the gain (as per Ken's suggestions) and it worked.

There should be a lot of tubes that can be used in this cct.

I put some 'scope shots up to give an idea of what it does
(scroll down)-

http://www.sdiy.org/pinky/MINISYN.html

once again, Thanks Ken!

Andrew

Re: CGS65 Tube VCA

2007-01-18 by Louis van Dompselaar

> I got this module running today. It is VERY good and does some very
> interesting things beyond regular VCA duties.

I'll second that! I just built two with the 1J24B tubes and they
are great.

Louis

Re: CGS65 Tube VCA

2007-01-18 by Fernando de Izuzquiza

Great scope pictures, thanks!

On the third image you get a pointy waveform from the triangle, how? with feedback? Or
somewhere with less gain than necessary for squaring it like in the fourth picture?

Very interesting processing anyway

Fernando
Show quoted textHide quoted text
> I put some 'scope shots up to give an idea of what it does
> (scroll down)-
>
> http://www.sdiy.org/pinky/MINISYN.html

Re: CGS65 Tube VCA

2007-01-18 by Richard Brewster

I am planning to build two of these with 1J24B tubes, too. I've
designed a panel with a two input mixer. The output goes to the second
input by jack normal connection for feedback. I am waiting for the
tubes to arrive from Russia. I bought 10 tubes. I am planning to keep
two extras, so I will have six left. I will probably offer them for
sale here.

Richard Brewster
http://www.pugix.com

Louis van Dompselaar wrote:
Show quoted textHide quoted text
>> I got this module running today. It is VERY good and does some very
>> interesting things beyond regular VCA duties.
>>
>
> I'll second that! I just built two with the 1J24B tubes and they
> are great.
>
> Louis
>
>
>

Re: CGS65 Tube VCA

2007-01-19 by bbluthang

Hi Fernando
> On the third image you get a pointy waveform from the triangle, how?
with feedback? Or
> somewhere with less gain than necessary for squaring it like in the
fourth picture?

haven't even tried feedback yet, these pics were taken whilst the PCB
was still on the bench. For most of them the CV source was a super
psycho LFO cranked up, I adjusted the LFOs amplitude for the pics.
The pics aren't in order but you can see some kind of PWM is possible
with this module. From memory, the pointy waveform came when
everything was going to 11.
The best results (IMHO) came from saw and sine waves.

regards
Andrew

Re: CGS65 Tube VCA

2007-01-19 by Fernando de Izuzquiza

Thanks Andrew.
So the control afects timbre in a more complex way than I thought (not just amplitude and
then drive) Very interesting.
I'll also say, thanks Ken once more!

Fernando
Show quoted textHide quoted text
>
> Hi Fernando
> > On the third image you get a pointy waveform from the triangle, how?
> with feedback? Or
> > somewhere with less gain than necessary for squaring it like in the
> fourth picture?
>
> haven't even tried feedback yet, these pics were taken whilst the PCB
> was still on the bench. For most of them the CV source was a super
> psycho LFO cranked up, I adjusted the LFOs amplitude for the pics.
> The pics aren't in order but you can see some kind of PWM is possible
> with this module. From memory, the pointy waveform came when
> everything was going to 11.
> The best results (IMHO) came from saw and sine waves.
>
> regards
> Andrew
>

Re: CGS65 Tube VCA

2007-01-19 by Jason Proctor

not that i can afford anything right now, but out of curiosity how
much are these tubes?

tx
Show quoted textHide quoted text
>I am planning to build two of these with 1J24B tubes, too. I've
>designed a panel with a two input mixer. The output goes to the second
>input by jack normal connection for feedback. I am waiting for the
>tubes to arrive from Russia. I bought 10 tubes. I am planning to keep
>two extras, so I will have six left. I will probably offer them for
>sale here.
>
>Richard Brewster
>http://www.pugix.com

Re: CGS65 Tube VCA

2007-01-19 by supisuzoi

I just got a 3-pack of unused 1J24B tubes for under 5 euro, including
shipping : )

soggy
Show quoted textHide quoted text
--- In cgs_synth@yahoogroups.com, Jason Proctor <jason@...> wrote:
>
> not that i can afford anything right now, but out of curiosity how
> much are these tubes?
>
> tx
>
>
> >I am planning to build two of these with 1J24B tubes, too. I've
> >designed a panel with a two input mixer. The output goes to the second
> >input by jack normal connection for feedback. I am waiting for the
> >tubes to arrive from Russia. I bought 10 tubes. I am planning to keep
> >two extras, so I will have six left. I will probably offer them for
> >sale here.
> >
> >Richard Brewster
> >http://www.pugix.com
>

Re: CGS65 Tube VCA

2007-01-19 by Richard Brewster

I got 10 1J24B on Ebay for $17 U.S. + $7 shipping. Paid for on December
28 and still awaiting their arrival from Russia in the mail. To those
who replied expressing interest, I will make an announcement when I want
to sell the extras. As for me, I am holding off buying the rest of the
parts until after I get these tubes. The FPE panel will cost me about
$90.00 US (a dual VCA panel). Well, you know me. Mr. Tick Marks. The
panel has 8 pots.

Richard Brewster
http://www.pugix.com

Jason Proctor wrote:
Show quoted textHide quoted text
> not that i can afford anything right now, but out of curiosity how
> much are these tubes?
>
> tx
>
>
>
>> I am planning to build two of these with 1J24B tubes, too. I've
>> designed a panel with a two input mixer. The output goes to the second
>> input by jack normal connection for feedback. I am waiting for the
>> tubes to arrive from Russia. I bought 10 tubes. I am planning to keep
>> two extras, so I will have six left. I will probably offer them for
>> sale here.
>>
>> Richard Brewster
>> http://www.pugix.com
>>
>
>
>
> The CGS Modular Synth home page: http://www.cgs.synth.net/
>
> Yahoo! Groups Links
>
>
>
>
>

Re: CGS65 Tube VCA

2007-01-20 by bbluthang

I got 6 sub-mini tubes for $1 (+ $7p&p), bought them a while ago,
before Ken released this PCB. Only 2 are pentodes though.
There are a couple of sellers on ebay that are always selling these
tubes, so easy to find.
Show quoted textHide quoted text
--- In cgs_synth@yahoogroups.com, Jason Proctor <jason@...> wrote:
>
> not that i can afford anything right now, but out of curiosity how
> much are these tubes?
>
> tx
>
>
> >I am planning to build two of these with 1J24B tubes, too. I've
> >designed a panel with a two input mixer. The output goes to the second
> >input by jack normal connection for feedback. I am waiting for the
> >tubes to arrive from Russia. I bought 10 tubes. I am planning to keep
> >two extras, so I will have six left. I will probably offer them for
> >sale here.
> >
> >Richard Brewster
> >http://www.pugix.com
>

Re: CGS65 Tube VCA

2007-01-20 by Fernando de Izuzquiza

The 1J24B also here:
http://www.engineersatwork.nl/catalog/product_info.php/products_id/522?
osCsid=79d4a4e1b1a6c35836c032688eecbd8a
And in some eBay shops, as said before.

The 1AG5 in Radiodaze and Vacuumtubes.

The CV4014 for CGS27 in dbtubes. Maybe they have some that can be used in CGS65 but I
don't know what are the specs to look for.

Fernando
Show quoted textHide quoted text
--- In cgs_synth@yahoogroups.com, "bbluthang" <jumpswine@...> wrote:
>
> I got 6 sub-mini tubes for $1 (+ $7p&p), bought them a while ago,
> before Ken released this PCB. Only 2 are pentodes though.
> There are a couple of sellers on ebay that are always selling these
> tubes, so easy to find.
>
> --- In cgs_synth@yahoogroups.com, Jason Proctor <jason@> wrote:
> >
> > not that i can afford anything right now, but out of curiosity how
> > much are these tubes?
> >
> > tx
> >
> >
> > >I am planning to build two of these with 1J24B tubes, too. I've
> > >designed a panel with a two input mixer. The output goes to the second
> > >input by jack normal connection for feedback. I am waiting for the
> > >tubes to arrive from Russia. I bought 10 tubes. I am planning to keep
> > >two extras, so I will have six left. I will probably offer them for
> > >sale here.
> > >
> > >Richard Brewster
> > >http://www.pugix.com
> >
>

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