Synth-DIY Yahoo! Groups Archives

VCO, NTO, PCO Instability,

2014-06-24 by dave.hamelin

Hello, i recently acquired an Animoo panel from 2013.

The problem:

In several different locations the VCO's pitches change when i move the power cables coming out of the panel, or when i touch the panel, or move around the panel. Basically the whole thing becomes an antenna and the VCO's cannot stay one one precise pitch. I've tried three different PSU's, tried without a PSD, tried replacing the power cables coming out of the panel. When the interference gets really bad, moving the VC Portamento pot on the NTO changes the pitch, as does changing the variable wave from full square (full CW) to less than full CW.

It does not exhibit this behaviour everywhere. In some places it is fine. but in many places it is not. I even had an electrician come to my house to make sure my power was ok and it was.

The pitches of both the NTO and PCO move together when they do. When i self-oscillate the filter though nothing interferes with its pitch.

I had a tech check all the grounds for continuity and according to him they all tested fine according to his calculations.

Any ideas?

Re: VCO, NTO, PCO Instability,

2014-06-24 by jimdenault

I had a similar problem when I first got my system (Haight era). At the time I was living within a mile of the hill with our city's radio and television broadcast antennas. I spoke to Serge, and the first thing he asked was if I was near any radio transmitters. He suggested a few modifications (shielding, capacitors across the power supply rails, etc.), but the only effective solution came when I moved.

Re: VCO, NTO, PCO Instability,

2014-06-24 by Richard Scott

wow, jim. That is a heck of a story!

On Tue, Jun 24, 2014 at 2:27 PM, jimdenault@... [SergeModular] <SergeModular@yahoogroups.com> wrote:

I had a similar problem when I first got my system (Haight era). At the time I was living within a mile of the hill with our city's radio and television broadcast antennas. I spoke to Serge, and the first thing he asked was if I was near any radio transmitters. He suggested a few modifications (shielding, capacitors across the power supply rails, etc.), but the only effective solution came when I moved.

Re: VCO, NTO, PCO Instability,

2014-06-24 by skkatter

Did the radio transmitter affect any other of the synths you owned or just the Serge?

-S

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On 24 June 2014 17:19, Richard Scott richard_scott@... [SergeModular] <SergeModular@yahoogroups.com> wrote:

wow, jim. That is a heck of a story!

On Tue, Jun 24, 2014 at 2:27 PM, jimdenault@... [SergeModular] <SergeModular@yahoogroups.com> wrote:

I had a similar problem when I first got my system (Haight era). At the time I was living within a mile of the hill with our city's radio and television broadcast antennas. I spoke to Serge, and the first thing he asked was if I was near any radio transmitters. He suggested a few modifications (shielding, capacitors across the power supply rails, etc.), but the only effective solution came when I moved.

Re: VCO, NTO, PCO Instability,

2014-06-24 by dave hamelin

No other synth I've ever had has had this problem.

Sent from Yahoo Mail for iPhone

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From: skkatter skkatter@... [SergeModular] <SergeModular@yahoogroups.com>;
To: <SergeModular@yahoogroups.com>;
Subject: Re: [SergeModular] Re: VCO, NTO, PCO Instability,
Sent: Tue, Jun 24, 2014 5:53:58 PM

Did the radio transmitter affect any other of the synths you owned or just the Serge?

-S

On 24 June 2014 17:19, Richard Scott richard_scott@... [SergeModular] <SergeModular@yahoogroups.com> wrote:

wow, jim. That is a heck of a story!

On Tue, Jun 24, 2014 at 2:27 PM, jimdenault@... [SergeModular] <SergeModular@yahoogroups.com> wrote:

I had a similar problem when I first got my system (Haight era). At the time I was living within a mile of the hill with our city's radio and television broadcast antennas. I spoke to Serge, and the first thing he asked was if I was near any radio transmitters. He suggested a few modifications (shielding, capacitors across the power supply rails, etc.), but the only effective solution came when I moved.

Re: VCO, NTO, PCO Instability,

2014-06-24 by jimdenault

We had an MS-20 and a mini-moog and neither of them were affected. We would occasionally pick up noise in one channel of a Fostex mixer. I kind of gave Serge a hard time about that. His response was that his system was more sensitive and complex, more like alchemy than science, and that I should just move.

Re: VCO, NTO, PCO Instability,

2014-06-24 by dave hamelin

That was pretty much the answer I got from Rex.

Sent from Yahoo Mail for iPhone

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From: jimdenault@... [SergeModular] <SergeModular@yahoogroups.com>;
To: <SergeModular@yahoogroups.com>;
Subject: [SergeModular] Re: VCO, NTO, PCO Instability,
Sent: Tue, Jun 24, 2014 10:24:47 PM

We had an MS-20 and a mini-moog and neither of them were affected. We would occasionally pick up noise in one channel of a Fostex mixer. I kind of gave Serge a hard time about that. His response was that his system was more sensitive and complex, more like alchemy than science, and that I should just move.

Re: VCO, NTO, PCO Instability,

2014-06-26 by dave.hamelin

Thanks Jim! that info was all I needed!