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CGS18 Drum simulator pitch drop question

CGS18 Drum simulator pitch drop question

2012-12-29 by Steve Inselman

Hello,
I have the twin-t drums with the res brought out to the front panel and a 500k pot from the 470k resistor which has given me a range from kick all the way up to a popping click. The pitch goes from the unmodified state on up but my question is how to drop it a couple octaves.

I know there are caps that can be altered in a 1 to 10 ratio but would I put higher or lower capacitors to get the desired effect?
What capacitor ratings would drop the kick about 2 octaves?

Has anybody tried this modification?


[Non-text portions of this message have been removed]

Re: CGS18 Drum simulator pitch drop question

2012-12-29 by sasami@hotkey.net.au

Double the value of the capacitor to halve the frequency = 1 oct down.
So 1n > 4n7 and 10n > 47n will give a bit over 2 octaves down for the 'kick'.
470p > 2n2 and 4n7 to 22n will give a bit over 2 octaves down for the other.
Show quoted textHide quoted text
>Hello,
>I have the twin-t drums with the res brought out to the front panel and a
500k pot from the 470k resistor which has given me a range from kick all the
way up to a popping click. The pitch goes from the unmodified state on up
but my question is how to drop it a couple octaves.
>
>I know there are caps that can be altered in a 1 to 10 ratio but would I
put higher or lower capacitors to get the desired effect?
>What capacitor ratings would drop the kick about 2 octaves?
>
>Has anybody tried this modification?
>
>
>[Non-text portions of this message have been removed]
>
>
>
>------------------------------------
>
>The CGS Modular Synth home page: http://www.cgs.synth.net/
>Yahoo! Groups Links
>
>
>
>
_______________________________________________________________________
Ken Stone sasami@... otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

Re: CGS18 Drum simulator pitch drop question

2012-12-30 by Steve Inselman

Great,
Thanks again Ken. I'll give it a shot. Hopefully I already have all the caps.

As for the Stiener VCF, I put a 2k pot on the res and it is self osc at close to half way and beyond that it is out of control It is very touchy. It goes out of control a the slightest adjustment.
The freq pot is still not opening up. I'll have to keep on troubleshooting.




________________________________
Show quoted textHide quoted text
From: "sasami@..." <sasami@...>
To: cgs_synth@yahoogroups.com
Sent: Saturday, December 29, 2012 4:50 PM
Subject: Re: [cgs_synth] CGS18 Drum simulator pitch drop question



Double the value of the capacitor to halve the frequency = 1 oct down.
So 1n > 4n7 and 10n > 47n will give a bit over 2 octaves down for the 'kick'.
470p > 2n2 and 4n7 to 22n will give a bit over 2 octaves down for the other.

>Hello,
>I have the twin-t drums with the res brought out to the front panel and a
500k pot from the 470k resistor which has given me a range from kick all the
way up to a popping click. The pitch goes from the unmodified state on up
but my question is how to drop it a couple octaves.
>
>I know there are caps that can be altered in a 1 to 10 ratio but would I
put higher or lower capacitors to get the desired effect?
>What capacitor ratings would drop the kick about 2 octaves?
>
>Has anybody tried this modification?
>
>
>[Non-text portions of this message have been removed]
>
>
>
>------------------------------------
>
>The CGS Modular Synth home page: http://www.cgs.synth.net/
>Yahoo! Groups Links
>
>
>
>
__________________________________________________________
Ken Stone sasami@... otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>




[Non-text portions of this message have been removed]

Re: CGS18 Drum simulator pitch drop question

2012-12-30 by sasami@hotkey.net.au

Resonance going out of control is a characteristic of the Sallen Key filter
type, so that is to be expected.
How many diodes do you have in your diode strings? What voltage are you
running at? If you are running on +/-12 and have all the diodes in, you may
have problems.
Ken
Show quoted textHide quoted text
>Great,
>Thanks again Ken. I'll give it a shot. Hopefully I already have all the caps.
>
>As for the Stiener VCF, I put a 2k pot on the res and it is self osc at
close to half way and beyond that it is out of control It is very touchy. It
goes out of control a the slightest adjustment.Â
>The freq pot is still not opening up. I'll have to keep on troubleshooting.Â
_______________________________________________________________________
Ken Stone sasami@... otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

Re: CGS18 Drum simulator pitch drop question

2012-12-30 by Steve Inselman

I'm running +/-15v. It is just a slight adjustment and it goes from minimal res to full on osc.
I placed all the diodes in as directed. I've been troubleshooting this one for weeks before I wrote.
I've tried everything I can think of.





________________________________
Show quoted textHide quoted text
From: "sasami@..." <sasami@...>
To: cgs_synth@yahoogroups.com
Sent: Sunday, December 30, 2012 4:06 PM
Subject: Re: [cgs_synth] CGS18 Drum simulator pitch drop question



Resonance going out of control is a characteristic of the Sallen Key filter
type, so that is to be expected.
How many diodes do you have in your diode strings? What voltage are you
running at? If you are running on +/-12 and have all the diodes in, you may
have problems.
Ken

>Great,
>Thanks again Ken. I'll give it a shot. Hopefully I already have all the caps.
>
>As for the Stiener VCF, I put a 2k pot on the res and it is self osc at
close to half way and beyond that it is out of control It is very touchy. It
goes out of control a the slightest adjustment.Â
>The freq pot is still not opening up. I'll have to keep on troubleshooting.Â
__________________________________________________________
Ken Stone sasami@... otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>




[Non-text portions of this message have been removed]

Re: CGS18 Drum simulator pitch drop question

2012-12-30 by sasami@hotkey.net.au

Perhaps try a different TYPE of transistor.
Ken
Show quoted textHide quoted text
>I'm running +/-15v. It is just a slight adjustment and it goes from minimal
res to full on osc.
>I placed all the diodes in as directed. I've been troubleshooting this one
for weeks before I wrote.
>I've tried everything I can think of.
>
>
>
>
>
>________________________________
> From: "sasami@..." <sasami@...>
>To: cgs_synth@yahoogroups.com
>Sent: Sunday, December 30, 2012 4:06 PM
>Subject: Re: [cgs_synth] CGS18 Drum simulator pitch drop question
>
>
>Â
>Resonance going out of control is a characteristic of the Sallen Key filter
>type, so that is to be expected.
>How many diodes do you have in your diode strings? What voltage are you
>running at? If you are running on +/-12 and have all the diodes in, you may
>have problems.
>Ken
>
>>Great,
>>Thanks again Ken. I'll give it a shot. Hopefully I already have all the caps.
>>
>>As for the Stiener VCF, I put a 2k pot on the res and it is self osc at
>close to half way and beyond that it is out of control It is very touchy. It
>goes out of control a the slightest adjustment.ÂÂ
>>The freq pot is still not opening up. I'll have to keep on
troubleshooting.ÂÂ
>__________________________________________________________
>Ken Stone sasami@... otherunicorn@...
>Modular Synth PCBs for sale <http://www.cgs.synth.net/>
>Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>
>
>
>
>
>[Non-text portions of this message have been removed]
>
>
>
>------------------------------------
>
>The CGS Modular Synth home page: http://www.cgs.synth.net/
>Yahoo! Groups Links
>
>
>
>
_______________________________________________________________________
Ken Stone sasami@... otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

Re: CGS18 Drum simulator Modification results list

2013-01-06 by Steve Inselman

I finally put the capacitors in and it works perfectly. It has a strong punchy low end BD on either side all the way up to clicking popping sounds. I highly recommend the modifications for a more versatile twin-t drum module.

500k pots where the 470k resistor is for pitch adjustment.

Change the capacitors: 1N to 4N7 and 10N-47N 470P-2N2 and 4N7-22N
They are the Caps connected to the 500k pots. This is to drop the pitch because the 500k pots only go from the unmodded pitch up to a click. These caps bring the Kick down to an almost unadioable range up to the popping sound (its a good sound) and the Tom down to a low BD up to the popping sound

Bring the Res to the front for "Decay" control. It lets the low BD ring longer to just a quick click. It is touchy when tuning it going into self-osc very easily.

Thanks for your help Ken.
Steve






________________________________
Show quoted textHide quoted text
From: "sasami@..." <sasami@...>
To: cgs_synth@yahoogroups.com
Sent: Saturday, December 29, 2012 4:50 PM
Subject: Re: [cgs_synth] CGS18 Drum simulator pitch drop question



Double the value of the capacitor to halve the frequency = 1 oct down.
So 1n > 4n7 and 10n > 47n will give a bit over 2 octaves down for the 'kick'.
470p > 2n2 and 4n7 to 22n will give a bit over 2 octaves down for the other.

>Hello,
>I have the twin-t drums with the res brought out to the front panel and a
500k pot from the 470k resistor which has given me a range from kick all the
way up to a popping click. The pitch goes from the unmodified state on up
but my question is how to drop it a couple octaves.
>
>I know there are caps that can be altered in a 1 to 10 ratio but would I
put higher or lower capacitors to get the desired effect?
>What capacitor ratings would drop the kick about 2 octaves?
>
>Has anybody tried this modification?
>
>
>[Non-text portions of this message have been removed]
>
>
>
>------------------------------------
>
>The CGS Modular Synth home page: http://www.cgs.synth.net/
>Yahoo! Groups Links
>
>
>
>
__________________________________________________________
Ken Stone sasami@... otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>




[Non-text portions of this message have been removed]

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