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CGS 202 Resonant Equalizer - high pitched noise on output.

CGS 202 Resonant Equalizer - high pitched noise on output.

2017-02-02 by Stephen Richards

I built the CGS 202 to incorporate into my new custom panel.

Since testing i had noticed a constant very high pitched (around 12K) noise in the background of the output , even though the normal function of the Res Eq seems fine.

I have used OP275 op amps in this build and styrenes for every single frequency. Wima caps everywhere else except the 47pF, which are ceramic.


Re: CGS 202 Resonant Equalizer - high pitched noise on output.

2017-02-03 by Ken Stone

use the correct op-amps.

On Fri, Feb 3, 2017 at 10:11 AM, Stephen Richards okayjustalittle@... [cgs_synth] <cgs_synth@yahoogroups.com> wrote:

I built the CGS 202 to incorporate into my new custom panel.

Since testing i had noticed a constant very high pitched (around 12K) noise in the background of the output , even though the normal function of the Res Eq seems fine.

I have used OP275 op amps in this build and styrenes for every single frequency. Wima caps everywhere else except the 47pF, which are ceramic.





--
Ken Stone otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>

Re: CGS 202 Resonant Equalizer - high pitched noise on output.

2017-02-03 by Stephen Richards

Thanks Ken.

The use of those was through the build thread on Muffs about three years ago. Jason suggested using those or OPA2134. So i decided then to try it. The RES EQ is mounted below the WAD. I'm going to test it without the WAD above it and see if the sound improves.

Show quoted textHide quoted text
From: "Ken Stone otherunicorn@... [cgs_synth]" <cgs_synth@yahoogroups.com>
To: cgs_synth@yahoogroups.com
Sent: Friday, February 3, 2017 1:57 PM
Subject: Re: [cgs_synth] CGS 202 Resonant Equalizer - high pitched noise on output.

use the correct op-amps.

On Fri, Feb 3, 2017 at 10:11 AM, Stephen Richards okayjustalittle@... [cgs_synth] <cgs_synth@yahoogroups.com> wrote:
I built the CGS 202 to incorporate into my new custom panel.

Since testing i had noticed a constant very high pitched (around 12K) noise in the background of the output , even though the normal function of the Res Eq seems fine.

I have used OP275 op amps in this build and styrenes for every single frequency. Wima caps everywhere else except the 47pF, which are ceramic.





--
Ken Stone otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>


Re: CGS 202 Resonant Equalizer - high pitched noise on output.

2017-02-03 by Ken Stone

If the whistle varied with the WAD delay, I'd expect it was picking up the WAD's internal clock, but if it remains fixed, it is probably an op-amp on the res eq itself oscillating. Really, you are wasting your money on expensive op-amps. The circuits were not designed with them in mind, and any "improvement" they may make would be so small you would not notice it unless you were using test gear.

On Fri, Feb 3, 2017 at 5:33 PM, Stephen Richards okayjustalittle@... [cgs_synth] <cgs_synth@yahoogroups.com> wrote:

Thanks Ken.

The use of those was through the build thread on Muffs about three years ago. Jason suggested using those or OPA2134. So i decided then to try it. The RES EQ is mounted below the WAD. I'm going to test it without the WAD above it and see if the sound improves.

Show quoted textHide quoted text
From: "Ken Stone otherunicorn@... [cgs_synth]" <cgs_synth@yahoogroups.com>
To: cgs_synth@yahoogroups.com
Sent: Friday, February 3, 2017 1:57 PM
Subject: Re: [cgs_synth] CGS 202 Resonant Equalizer - high pitched noise on output.

use the correct op-amps.

On Fri, Feb 3, 2017 at 10:11 AM, Stephen Richards okayjustalittle@... [cgs_synth] <cgs_synth@yahoogroups.com> wrote:
I built the CGS 202 to incorporate into my new custom panel.

Since testing i had noticed a constant very high pitched (around 12K) noise in the background of the output , even though the normal function of the Res Eq seems fine.

I have used OP275 op amps in this build and styrenes for every single frequency. Wima caps everywhere else except the 47pF, which are ceramic.





--
Ken Stone otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>





--
Ken Stone otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>

AW: [cgs_synth] CGS 202 Resonant Equalizer - high pitched noise on o

2017-02-03 by Paul Schulz

Well, there is a difference in the ResEq's sound between cheap and expensive opamps when pinging/ringing it to create percussions - not in that much when using it as an audio processor.
The cheap opamps created a more aggressive sound and had more smack, more attack (maybe just because of distortion?) while the expensive chips were more transparent but slightly boring.

Cheers,
Paul


_ _ _ _ _
Sent from my Commodore C64
Von: Ken Stone otherunicorn@... [cgs_synth]
Gesendet: ‎03.‎02.‎2017 08:04
An: cgs_synth@yahoogroups.com
Betreff: Re: [cgs_synth] CGS 202 Resonant Equalizer - high pitched noise on output.

If the whistle varied with the WAD delay, I'd expect it was picking up the WAD's internal clock, but if it remains fixed, it is probably an op-amp on the res eq itself oscillating. Really, you are wasting your money on expensive op-amps. The circuits were not designed with them in mind, and any "improvement" they may make would be so small you would not notice it unless you were using test gear.

On Fri, Feb 3, 2017 at 5:33 PM, Stephen Richards okayjustalittle@... [cgs_synth] <cgs_synth@yahoogroups.com> wrote:

Thanks Ken.

The use of those was through the build thread on Muffs about three years ago. Jason suggested using those or OPA2134. So i decided then to try it. The RES EQ is mounted below the WAD. I'm going to test it without the WAD above it and see if the sound improves.

Show quoted textHide quoted text

From: "Ken Stone otherunicorn@... [cgs_synth]" <cgs_synth@yahoogroups.com>
To: cgs_synth@yahoogroups.com
Sent: Friday, February 3, 2017 1:57 PM
Subject: Re: [cgs_synth] CGS 202 Resonant Equalizer - high pitched noise on output.

use the correct op-amps.

On Fri, Feb 3, 2017 at 10:11 AM, Stephen Richards okayjustalittle@... [cgs_synth] <cgs_synth@yahoogroups.com> wrote:
I built the CGS 202 to incorporate into my new custom panel.

Since testing i had noticed a constant very high pitched (around 12K) noise in the background of the output , even though the normal function of the Res Eq seems fine.

I have used OP275 op amps in this build and styrenes for every single frequency. Wima caps everywhere else except the 47pF, which are ceramic.





--
Ken Stone otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>


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