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Super Psycho LFO and Synthacon VCF problems...

Super Psycho LFO and Synthacon VCF problems...

2009-01-17 by alll_78

Hello to all, I'm having a few problems building the two modules in the
subject...
I finished soldering and wiring the Super Psycho modulation source,
checked many times the correct position (and polarity) of all the
components, the board presents no failure at all, and solderings are
clean with no shorts, but as soon as I powered it, I got it "smoking"
from the first 10uF ele cap just next to the -15V input...
About the VCF, I find a really little range of frequency control.
Maybe anyone can help me?
Thank you very much!

Re: Super Psycho LFO and Synthacon VCF problems...

2009-01-23 by Jon

Hi,

If you get magic smoke it's often due to a short or something in the
wrong position. Check and check and double check again?

The frequency range can be adjusted if you read on the Synthacon page
you can see how: http://cgs.synth.net/modules/cgs35_syntha_vcf.html

"FREQ knob adjustment. As stated, my original range of 0 to 5 (out of
10) covered 20 Hz to 20 KHz. There are two resistors to adjust for
this. First, decreasing the size of the input divider resistor on the
CV input section, 1K in Ken's circuit, increases the range of the
frequency control. I put 2.2K in parallel with the 1K resistors, or you
can swap the 1K with a 680 ohm resistor. Note that this also affects
the Control voltage inputs, so they will need to be adjusted. I also
added 220K of series resistance to the FREQ knob. This tends to center
the frequencies on the FREQ knob so 200 Hz is near the center. With
these values the knob range 0 to 10 sweeps approximately 5 Hz to 25
KHz. This was measured by putting 20 Hz and 20KHz sine waves into the
LPF input and measuring the amplitudes at min and max FREQ positions. I
also tested audibly using white noise as an input. "

Cheers!
//Jon
Show quoted textHide quoted text
--- In cgs_synth@yahoogroups.com, "alll_78" <sergiosigoni@...> wrote:
>
> Hello to all, I'm having a few problems building the two modules in
the
> subject...
> I finished soldering and wiring the Super Psycho modulation source,
> checked many times the correct position (and polarity) of all the
> components, the board presents no failure at all, and solderings are
> clean with no shorts, but as soon as I powered it, I got it "smoking"
> from the first 10uF ele cap just next to the -15V input...
> About the VCF, I find a really little range of frequency control.
> Maybe anyone can help me?
> Thank you very much!
>

Re: Super Psycho LFO and Synthacon VCF problems...

2009-01-23 by Ken Stone

You either have a part in backwards, the power connected backwards, or
perhaps (and highly unlikely) a faulty part. If it has happened to
more than 1 part in the same location, it is definitely something you
are doing wrong.
Show quoted textHide quoted text
--- In cgs_synth@yahoogroups.com, "alll_78" <sergiosigoni@...> wrote:
>
> Hello to all, I'm having a few problems building the two modules in the
> subject...
> I finished soldering and wiring the Super Psycho modulation source,
> checked many times the correct position (and polarity) of all the
> components, the board presents no failure at all, and solderings are
> clean with no shorts, but as soon as I powered it, I got it "smoking"
> from the first 10uF ele cap just next to the -15V input...
> About the VCF, I find a really little range of frequency control.
> Maybe anyone can help me?
> Thank you very much!
>

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