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Best of CGS Panel #3 Oscillator signal bleed problem

Best of CGS Panel #3 Oscillator signal bleed problem

2011-10-17 by Stephen

Hi Ken and All

I built the Best of CGS Panel #3 last year and i have never been able to get rid of the signal bleed from the CGS 48 oscillators.

To describe what is happening : Even with nothing patched ; when i plug the panel's output into a mixer , even with the output turned all the way down , i can still hear the oscillators in the background regardless of whether i take my output signal from VCA's or from the Dual Mixer.

I am powering the panel with and elby all in one power module 30VA +/-15VDC.

I'm using a split output cable with the Earth coming off the Sleeve , Output signal is on the Tip. That Earth from the cable goes to a Banana Jack connected to the Power Module's main Earth Stud.

On the 15V side of the Power Module + , - and Earth is connected to the panel via CGS Distro which is insulated from the Chassis.

I have not taken any Earth Connection directly to the Chassis.

many thanks

Stephen

Re: Best of CGS Panel #3 Oscillator signal bleed problem

2011-10-17 by sasami@hotkey.net.au

Things to try:
1) increase the size of the decoupling capacitors near the oscillator power
connetions. Add 100n caps there as well.
2) Run a separate set of wires from the oscillators to the power supply, so
that the oscillators and the other circuits are not sharing the same wires.
3) Use a bigger power supply, or a second supply to power just the
oscillators. The two power supplies would need their 0V lines connected to
each other, but NOT the other lines.
Ken
Show quoted textHide quoted text
>Hi Ken and All
>
>I built the Best of CGS Panel #3 last year and i have never been able to
get rid of the signal bleed from the CGS 48 oscillators.
>
>To describe what is happening : Even with nothing patched ; when i plug the
panel's output into a mixer , even with the output turned all the way down ,
i can still hear the oscillators in the background regardless of whether i
take my output signal from VCA's or from the Dual Mixer.
>
>I am powering the panel with and elby all in one power module 30VA +/-15VDC.
>
>I'm using a split output cable with the Earth coming off the Sleeve ,
Output signal is on the Tip. That Earth from the cable goes to a Banana Jack
connected to the Power Module's main Earth Stud.
>
>On the 15V side of the Power Module + , - and Earth is connected to the
panel via CGS Distro which is insulated from the Chassis.
>
>I have not taken any Earth Connection directly to the Chassis.
>
>many thanks
>
>Stephen
>
>
>
>
>
>
>
>------------------------------------
>
>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: Best of CGS Panel #3 Oscillator signal bleed problem

2011-10-17 by magman2112

Hi Stephen,

Can I double check with you about the signal ground connections?

On the PSU are you connecting to the chassis mains earth or the 0V (ground) connection, as you should definitely be using the 0V connection? The signals in the CGS48 oscillator are with reference to 0V and the Elby PSU may not connect the mains earth directly to the 0V.

On my Best of CGS panels, I used one of Ken's CGS66 PSU's. This actually has provision for a "Star Earth" point which is at 0V on the PSU side (not the mains), I connected a banana jack to this point on the outside of my case and use this to connect to other equipment so the ground levels are commoned. The mains earth is connected to the metal front panel only.

Hope this helps

Regards

Mike
Show quoted textHide quoted text
--- In cgs_synth@yahoogroups.com, "Stephen" <okayjustalittle@...> wrote:
>
> Hi Ken and All
>
> I built the Best of CGS Panel #3 last year and i have never been able to get rid of the signal bleed from the CGS 48 oscillators.
>
> To describe what is happening : Even with nothing patched ; when i plug the panel's output into a mixer , even with the output turned all the way down , i can still hear the oscillators in the background regardless of whether i take my output signal from VCA's or from the Dual Mixer.
>
> I am powering the panel with and elby all in one power module 30VA +/-15VDC.
>
> I'm using a split output cable with the Earth coming off the Sleeve , Output signal is on the Tip. That Earth from the cable goes to a Banana Jack connected to the Power Module's main Earth Stud.
>
> On the 15V side of the Power Module + , - and Earth is connected to the panel via CGS Distro which is insulated from the Chassis.
>
> I have not taken any Earth Connection directly to the Chassis.
>
> many thanks
>
> Stephen
>

Re: Best of CGS Panel #3 Oscillator signal bleed problem

2011-10-17 by Stephen Richards

Thanks Ken , I'll try it out.

Stephen


________________________________
Show quoted textHide quoted text
From: "sasami@..." <sasami@...>
To: cgs_synth@yahoogroups.com
Sent: Monday, October 17, 2011 5:05 PM
Subject: Re: [cgs_synth] Best of CGS Panel #3 Oscillator signal bleed problem



Things to try:
1) increase the size of the decoupling capacitors near the oscillator power
connetions. Add 100n caps there as well.
2) Run a separate set of wires from the oscillators to the power supply, so
that the oscillators and the other circuits are not sharing the same wires.
3) Use a bigger power supply, or a second supply to power just the
oscillators. The two power supplies would need their 0V lines connected to
each other, but NOT the other lines.
Ken

>Hi Ken and All
>
>I built the Best of CGS Panel #3 last year and i have never been able to
get rid of the signal bleed from the CGS 48 oscillators.
>
>To describe what is happening : Even with nothing patched ; when i plug the
panel's output into a mixer , even with the output turned all the way down ,
i can still hear the oscillators in the background regardless of whether i
take my output signal from VCA's or from the Dual Mixer.
>
>I am powering the panel with and elby all in one power module 30VA +/-15VDC.
>
>I'm using a split output cable with the Earth coming off the Sleeve ,
Output signal is on the Tip. That Earth from the cable goes to a Banana Jack
connected to the Power Module's main Earth Stud.
>
>On the 15V side of the Power Module + , - and Earth is connected to the
panel via CGS Distro which is insulated from the Chassis.
>
>I have not taken any Earth Connection directly to the Chassis.
>
>many thanks
>
>Stephen
>
>
>
>
>
>
>
>------------------------------------
>
>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: Best of CGS Panel #3 Oscillator signal bleed problem

2011-10-17 by Stephen Richards

Hi Mike

I'm connected to the Main Earth Stud on the 240V side for the Signal Out Ground Connection.

So i should connect Signal Out Ground Connection to the Ground on the 15V side , is that correct ?

Do any of the Earth / Ground connections need to be physically connected to the Chassis ?

I'm going to keep my Signal Out Ground connection at the Power Module is it is at the beginning point for multiple module connections.

My module power connections are Daisy chained pre CGS distro boards.

cheers for the help

Stephen

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

Re: Best of CGS Panel #3 Oscillator signal bleed problem

2011-10-17 by magman2112

Hi Stephen,

I think this may be part of your problem, you should definitely be using the 15V side for you signal ground connection.

Think of it this way. The output of the oscillator is a varying voltage - or potential difference. This potential difference has to be "different" to something, which is the 0V rail of the PSU.

By connecting to the mains earth, you are relying on some other connection to provide the reference voltage for the oscillator, which can cause all kinds of problems.

Earthing of metalwork is a completely different issue and can be quite complex. I'm not an electrician, so can't give an authoritative point of view, but in this case, because the Mains is outside of the case, you shouldn't need a PPE (Power Protective Earth). If the mains is inside the case though, all metal panels should be electrically bonded together.

Personally, I prefer to earth everything, just to be on the safe side. I pick one place as the 'Earth Bonding Point' and star-wire earth connections back to this point for any metalwork.

Hope this helps.

Regards

Mike

Hope this helps
Show quoted textHide quoted text
--- In cgs_synth@yahoogroups.com, Stephen Richards <okayjustalittle@...> wrote:
>
> Hi Mike
>
> I'm connected to the Main Earth Stud on the 240V side for the Signal Out Ground Connection.
>
> So i should connect Signal Out Ground Connection to the Ground on the 15V side , is that correct ?
>
> Do any of the Earth / Ground connections need to be physically connected to the Chassis ?
>
> I'm going to keep my Signal Out Ground connection at the Power Module is it is at the beginning point for multiple module connections.
>
> My module power connections are Daisy chained pre CGS distro boards.
>
> cheers for the help
>
> Stephen
>
> [Non-text portions of this message have been removed]
>

Re: Best of CGS Panel #3 Oscillator signal bleed problem

2011-10-17 by sasami@hotkey.net.au

I never connect my signal ground directly to mains ground. I always put a 1k
1 watt resistor between the two. This helps prevent ground/hum loops. That
also means that my panels cannot be mounted hard to a metal case that is
grounded to mains earth. I solve that by having my power supplies in their
own metal cases which are earthed to mains earth. The resistor between 0V
and mains earth is then installed in the power supply. If the power supply
needs to go into the same case as the rest of the synth, the power supply's
own smaller cabinet is mounted using some sort of insulators, such as small
rubber shock mounts, and the 0V connection is connected to the panel/case
earth.

Ken
Show quoted textHide quoted text
>Hi Mike
>
>I'm connected to the Main Earth Stud on the 240V side for the Signal
Out Ground Connection.
>
>So i should connect Signal Out Ground Connection to the Ground on the 15V
side , is that correct ?
>
>Do any of the Earth / Ground connections need to be physically connected to
the Chassis ?
>
>I'm going to keep my Signal Out Ground connection at the Power Module is it
is at the beginning point for multiple module connections.
>
>My module power connections are Daisy chained pre CGS distro boards.
>
>cheers for the help
>
>Stephen
>
>[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: Best of CGS Panel #3 Oscillator signal bleed problem

2011-10-17 by Stephen Richards

Thanks again Ken and Mike ; I'm going to have to digest this all.

This is what i now have : I have just removed the Banana Jack Signal Ground from the Earth Stud and connected it to one of two 0V on the 15V side of the Power Module. (this is the only change i have ever made to the power setup).

To Banana Jack Signal Ground i connect the sleeve of my Synth Panel Output Cable. Tip is Signal. The Banana Jack is mounted to the side wall of the same Hammond Metal Box that contains the Power Module but it is a plastic jack so insulated from the Box.

Removing the Banana Jack Signal Ground from the Earth Stud has made zero difference to my original problem.

In fact , as before/always ; the Signal Ground does not make any difference connected or otherwise ! I completely stumped here.

When you say you never connect the Signal Ground to Mains Ground directly ,
should i run my Signal Ground on the 15V side back to the Earth Stud via a 1K 1 Watt resistor ?

In regards to the Hammond box metal , do i need to ground that to the Earth Stud ?

Stephen


________________________________
Show quoted textHide quoted text
From: "sasami@..." <sasami@...>
To: cgs_synth@yahoogroups.com
Sent: Monday, October 17, 2011 8:24 PM
Subject: Re: [cgs_synth] Re: Best of CGS Panel #3 Oscillator signal bleed problem



I never connect my signal ground directly to mains ground. I always put a 1k
1 watt resistor between the two. This helps prevent ground/hum loops. That
also means that my panels cannot be mounted hard to a metal case that is
grounded to mains earth. I solve that by having my power supplies in their
own metal cases which are earthed to mains earth. The resistor between 0V
and mains earth is then installed in the power supply. If the power supply
needs to go into the same case as the rest of the synth, the power supply's
own smaller cabinet is mounted using some sort of insulators, such as small
rubber shock mounts, and the 0V connection is connected to the panel/case
earth.

Ken

>Hi Mike
>
>I'm connected to the Main Earth Stud on the 240V side for the Signal
Out Ground Connection.
>
>So i should connect Signal Out Ground Connection to the Ground on the 15V
side , is that correct ?
>
>Do any of the Earth / Ground connections need to be physically connected to
the Chassis ?
>
>I'm going to keep my Signal Out Ground connection at the Power Module is it
is at the beginning point for multiple module connections.
>
>My module power connections are Daisy chained pre CGS distro boards.
>
>cheers for the help
>
>Stephen
>
>[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: Best of CGS Panel #3 Oscillator signal bleed problem

2011-10-17 by Elby Designs

You should also note that there is a link on the All-In-One that connects the DC 0V to EARTH so you need to establish if that is fitted or not.

Best Regards
Laurie Biddulph
Mobile: 0400 257 645
Web: www.elby-designs.com

-----Original Message-----
Show quoted textHide quoted text
From: cgs_synth@yahoogroups.com [mailto:cgs_synth@yahoogroups.com] On Behalf Of Stephen Richards
Sent: Monday, 17 October 2011 10:32 PM
To: cgs_synth@yahoogroups.com
Subject: Re: [cgs_synth] Re: Best of CGS Panel #3 Oscillator signal bleed problem

Thanks again Ken and Mike ; I'm going to have to digest this all.

This is what i now have : I have just removed the Banana Jack Signal Ground from the Earth Stud and connected it to one of two 0V on the 15V side of the Power Module. (this is the only change i have ever made to the power setup).

To Banana Jack Signal Ground i connect the sleeve of my Synth Panel Output Cable. Tip is Signal. The Banana Jack is mounted to the side wall of the same Hammond Metal Box that contains the Power Module but it is a plastic jack so insulated from the Box.

Removing the Banana Jack Signal Ground from the Earth Stud has made zero difference to my original problem.

In fact , as before/always ; the Signal Ground does not make any difference connected or otherwise ! I completely stumped here.

When you say you never connect the Signal Ground to Mains Ground directly ,
should i run my Signal Ground on the 15V side back to the Earth Stud via a 1K 1 Watt resistor ?

In regards to the Hammond box metal , do i need to ground that to the Earth Stud ?

Stephen


________________________________
From: "sasami@..." <sasami@...>
To: cgs_synth@yahoogroups.com
Sent: Monday, October 17, 2011 8:24 PM
Subject: Re: [cgs_synth] Re: Best of CGS Panel #3 Oscillator signal bleed problem



I never connect my signal ground directly to mains ground. I always put a 1k
1 watt resistor between the two. This helps prevent ground/hum loops. That
also means that my panels cannot be mounted hard to a metal case that is
grounded to mains earth. I solve that by having my power supplies in their
own metal cases which are earthed to mains earth. The resistor between 0V
and mains earth is then installed in the power supply. If the power supply
needs to go into the same case as the rest of the synth, the power supply's
own smaller cabinet is mounted using some sort of insulators, such as small
rubber shock mounts, and the 0V connection is connected to the panel/case
earth.

Ken

>Hi Mike
>
>I'm connected to the Main Earth Stud on the 240V side for the Signal
Out Ground Connection.
>
>So i should connect Signal Out Ground Connection to the Ground on the 15V
side , is that correct ?
>
>Do any of the Earth / Ground connections need to be physically connected to
the Chassis ?
>
>I'm going to keep my Signal Out Ground connection at the Power Module is it
is at the beginning point for multiple module connections.
>
>My module power connections are Daisy chained pre CGS distro boards.
>
>cheers for the help
>
>Stephen
>
>[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]



------------------------------------

The CGS Modular Synth home page: http://www.cgs.synth.net/
Yahoo! Groups Links

Re: Best of CGS Panel #3 Oscillator signal bleed problem

2011-10-17 by Stephen Richards

Thanks Laurie , i'll check it tomorrow.


________________________________
Show quoted textHide quoted text
From: Elby Designs <elby_designs@...>
To: cgs_synth@yahoogroups.com
Sent: Monday, October 17, 2011 10:46 PM
Subject: RE: [cgs_synth] Re: Best of CGS Panel #3 Oscillator signal bleed problem



You should also note that there is a link on the All-In-One that connects the DC 0V to EARTH so you need to establish if that is fitted or not.

Best Regards
Laurie Biddulph
Mobile: 0400 257 645
Web: www.elby-designs.com

-----Original Message-----
From: cgs_synth@yahoogroups.com [mailto:cgs_synth@yahoogroups.com] On Behalf Of Stephen Richards
Sent: Monday, 17 October 2011 10:32 PM
To: cgs_synth@yahoogroups.com
Subject: Re: [cgs_synth] Re: Best of CGS Panel #3 Oscillator signal bleed problem

Thanks again Ken and Mike ; I'm going to have to digest this all.

This is what i now have : I have just removed the Banana Jack Signal Ground from the Earth Stud and connected it to one of two 0V on the 15V side of the Power Module. (this is the only change i have ever made to the power setup).

To Banana Jack Signal Ground i connect the sleeve of my Synth Panel Output Cable. Tip is Signal. The Banana Jack is mounted to the side wall of the same Hammond Metal Box that contains the Power Module but it is a plastic jack so insulated from the Box.

Removing the Banana Jack Signal Ground from the Earth Stud has made zero difference to my original problem.

In fact , as before/always ; the Signal Ground does not make any difference connected or otherwise ! I completely stumped here.

When you say you never connect the Signal Ground to Mains Ground directly ,
should i run my Signal Ground on the 15V side back to the Earth Stud via a 1K 1 Watt resistor ?

In regards to the Hammond box metal , do i need to ground that to the Earth Stud ?

Stephen

________________________________
From: "sasami@..." <sasami@...>
To: cgs_synth@yahoogroups.com
Sent: Monday, October 17, 2011 8:24 PM
Subject: Re: [cgs_synth] Re: Best of CGS Panel #3 Oscillator signal bleed problem

I never connect my signal ground directly to mains ground. I always put a 1k
1 watt resistor between the two. This helps prevent ground/hum loops. That
also means that my panels cannot be mounted hard to a metal case that is
grounded to mains earth. I solve that by having my power supplies in their
own metal cases which are earthed to mains earth. The resistor between 0V
and mains earth is then installed in the power supply. If the power supply
needs to go into the same case as the rest of the synth, the power supply's
own smaller cabinet is mounted using some sort of insulators, such as small
rubber shock mounts, and the 0V connection is connected to the panel/case
earth.

Ken

>Hi Mike
>
>I'm connected to the Main Earth Stud on the 240V side for the Signal
Out Ground Connection.
>
>So i should connect Signal Out Ground Connection to the Ground on the 15V
side , is that correct ?
>
>Do any of the Earth / Ground connections need to be physically connected to
the Chassis ?
>
>I'm going to keep my Signal Out Ground connection at the Power Module is it
is at the beginning point for multiple module connections.
>
>My module power connections are Daisy chained pre CGS distro boards.
>
>cheers for the help
>
>Stephen
>
>[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]

------------------------------------

The CGS Modular Synth home page: http://www.cgs.synth.net/
Yahoo! Groups Links




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

Re: Best of CGS Panel #3 Oscillator signal bleed problem

2011-10-17 by Stephen Richards

Hi Laurie

If you mean JP1 , then yes it is fitted ; wire link.

Stephen


________________________________
Show quoted textHide quoted text
From: Elby Designs <elby_designs@...>
To: cgs_synth@yahoogroups.com
Sent: Monday, October 17, 2011 10:46 PM
Subject: RE: [cgs_synth] Re: Best of CGS Panel #3 Oscillator signal bleed problem



You should also note that there is a link on the All-In-One that connects the DC 0V to EARTH so you need to establish if that is fitted or not.

Best Regards
Laurie Biddulph
Mobile: 0400 257 645
Web: www.elby-designs.com

-----Original Message-----
From: cgs_synth@yahoogroups.com [mailto:cgs_synth@yahoogroups.com] On Behalf Of Stephen Richards
Sent: Monday, 17 October 2011 10:32 PM
To: cgs_synth@yahoogroups.com
Subject: Re: [cgs_synth] Re: Best of CGS Panel #3 Oscillator signal bleed problem

Thanks again Ken and Mike ; I'm going to have to digest this all.

This is what i now have : I have just removed the Banana Jack Signal Ground from the Earth Stud and connected it to one of two 0V on the 15V side of the Power Module. (this is the only change i have ever made to the power setup).

To Banana Jack Signal Ground i connect the sleeve of my Synth Panel Output Cable. Tip is Signal. The Banana Jack is mounted to the side wall of the same Hammond Metal Box that contains the Power Module but it is a plastic jack so insulated from the Box.

Removing the Banana Jack Signal Ground from the Earth Stud has made zero difference to my original problem.

In fact , as before/always ; the Signal Ground does not make any difference connected or otherwise ! I completely stumped here.

When you say you never connect the Signal Ground to Mains Ground directly ,
should i run my Signal Ground on the 15V side back to the Earth Stud via a 1K 1 Watt resistor ?

In regards to the Hammond box metal , do i need to ground that to the Earth Stud ?

Stephen

________________________________
From: "sasami@..." <sasami@...>
To: cgs_synth@yahoogroups.com
Sent: Monday, October 17, 2011 8:24 PM
Subject: Re: [cgs_synth] Re: Best of CGS Panel #3 Oscillator signal bleed problem

I never connect my signal ground directly to mains ground. I always put a 1k
1 watt resistor between the two. This helps prevent ground/hum loops. That
also means that my panels cannot be mounted hard to a metal case that is
grounded to mains earth. I solve that by having my power supplies in their
own metal cases which are earthed to mains earth. The resistor between 0V
and mains earth is then installed in the power supply. If the power supply
needs to go into the same case as the rest of the synth, the power supply's
own smaller cabinet is mounted using some sort of insulators, such as small
rubber shock mounts, and the 0V connection is connected to the panel/case
earth.

Ken

>Hi Mike
>
>I'm connected to the Main Earth Stud on the 240V side for the Signal
Out Ground Connection.
>
>So i should connect Signal Out Ground Connection to the Ground on the 15V
side , is that correct ?
>
>Do any of the Earth / Ground connections need to be physically connected to
the Chassis ?
>
>I'm going to keep my Signal Out Ground connection at the Power Module is it
is at the beginning point for multiple module connections.
>
>My module power connections are Daisy chained pre CGS distro boards.
>
>cheers for the help
>
>Stephen
>
>[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]

------------------------------------

The CGS Modular Synth home page: http://www.cgs.synth.net/
Yahoo! Groups Links




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

Re: Best of CGS Panel #3 Oscillator signal bleed problem

2011-10-17 by Elby Designs

That link is there to connect the two grounds (0V and EARTH) together. In a `proper' system this should be linked as it keeps EVERYTHING at EARTH potential and electrically safe.
This link can be removed or, better still, replaced with a resistor to help control earth loops but you need to take other precautions then to ensure the integrity of your systems earthing. All metal work should really be connected to EARTH but note that many modules (especially Panthers) will provide a ground connection to the panel at the module. In an ideal system this would actually be a `panel ground' or earth or something supplied to the system through a dedicated wire on the distribution system. Unfortunately Doepfer and even MOTM decided not to offer this important feature and so it has to be addressed a different way. If you look at the Oakley system you will see that he DOES do this and it works perfect as long as you only use Oakley modules.

Best Regards
Laurie Biddulph
Mobile: 0400 257 645
Web: www.elby-designs.com

-----Original Message-----
Show quoted textHide quoted text
From: cgs_synth@yahoogroups.com [mailto:cgs_synth@yahoogroups.com] On Behalf Of Stephen Richards
Sent: Tuesday, 18 October 2011 12:33 AM
To: cgs_synth@yahoogroups.com
Subject: Re: [cgs_synth] Re: Best of CGS Panel #3 Oscillator signal bleed problem

Hi Laurie

If you mean JP1 , then yes it is fitted ; wire link.

Stephen


________________________________
From: Elby Designs <elby_designs@...>
To: cgs_synth@yahoogroups.com
Sent: Monday, October 17, 2011 10:46 PM
Subject: RE: [cgs_synth] Re: Best of CGS Panel #3 Oscillator signal bleed problem



You should also note that there is a link on the All-In-One that connects the DC 0V to EARTH so you need to establish if that is fitted or not.

Best Regards
Laurie Biddulph
Mobile: 0400 257 645
Web: www.elby-designs.com

-----Original Message-----
From: cgs_synth@yahoogroups.com [mailto:cgs_synth@yahoogroups.com] On Behalf Of Stephen Richards
Sent: Monday, 17 October 2011 10:32 PM
To: cgs_synth@yahoogroups.com
Subject: Re: [cgs_synth] Re: Best of CGS Panel #3 Oscillator signal bleed problem

Thanks again Ken and Mike ; I'm going to have to digest this all.

This is what i now have : I have just removed the Banana Jack Signal Ground from the Earth Stud and connected it to one of two 0V on the 15V side of the Power Module. (this is the only change i have ever made to the power setup).

To Banana Jack Signal Ground i connect the sleeve of my Synth Panel Output Cable. Tip is Signal. The Banana Jack is mounted to the side wall of the same Hammond Metal Box that contains the Power Module but it is a plastic jack so insulated from the Box.

Removing the Banana Jack Signal Ground from the Earth Stud has made zero difference to my original problem.

In fact , as before/always ; the Signal Ground does not make any difference connected or otherwise ! I completely stumped here.

When you say you never connect the Signal Ground to Mains Ground directly ,
should i run my Signal Ground on the 15V side back to the Earth Stud via a 1K 1 Watt resistor ?

In regards to the Hammond box metal , do i need to ground that to the Earth Stud ?

Stephen

________________________________
From: "sasami@..." <sasami@...>
To: cgs_synth@yahoogroups.com
Sent: Monday, October 17, 2011 8:24 PM
Subject: Re: [cgs_synth] Re: Best of CGS Panel #3 Oscillator signal bleed problem

I never connect my signal ground directly to mains ground. I always put a 1k
1 watt resistor between the two. This helps prevent ground/hum loops. That
also means that my panels cannot be mounted hard to a metal case that is
grounded to mains earth. I solve that by having my power supplies in their
own metal cases which are earthed to mains earth. The resistor between 0V
and mains earth is then installed in the power supply. If the power supply
needs to go into the same case as the rest of the synth, the power supply's
own smaller cabinet is mounted using some sort of insulators, such as small
rubber shock mounts, and the 0V connection is connected to the panel/case
earth.

Ken

>Hi Mike
>
>I'm connected to the Main Earth Stud on the 240V side for the Signal
Out Ground Connection.
>
>So i should connect Signal Out Ground Connection to the Ground on the 15V
side , is that correct ?
>
>Do any of the Earth / Ground connections need to be physically connected to
the Chassis ?
>
>I'm going to keep my Signal Out Ground connection at the Power Module is it
is at the beginning point for multiple module connections.
>
>My module power connections are Daisy chained pre CGS distro boards.
>
>cheers for the help
>
>Stephen
>
>[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]

------------------------------------

The CGS Modular Synth home page: http://www.cgs.synth.net/
Yahoo! Groups Links




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



------------------------------------

The CGS Modular Synth home page: http://www.cgs.synth.net/
Yahoo! Groups Links

Re: Best of CGS Panel #3 Oscillator signal bleed problem

2011-10-18 by Stephen Richards

Hi Ken

This thread has got a bit bogged down in talking about Earth Connections in my Power Supply , sorry.

Getting back to my original query...you suggested increasing the Decoupling Caps value.

We are talking about the 10uf 35V x2 and the 100n x2 on each Oscillator , yes ?

Should i try for something like 22uf for the electrolitics and whatever is the next value up for he Ceramics ?

Also , your suggestion for the 1K 1 watt resistor for the Signal ground ; would i install this between the 0V out of the 15V side of my Power Module and before the Banana Jack for my signal ground ?



________________________________
Show quoted textHide quoted text
From: "sasami@..." <sasami@...>
To: cgs_synth@yahoogroups.com
Sent: Monday, October 17, 2011 8:24 PM
Subject: Re: [cgs_synth] Re: Best of CGS Panel #3 Oscillator signal bleed problem



I never connect my signal ground directly to mains ground. I always put a 1k
1 watt resistor between the two. This helps prevent ground/hum loops. That
also means that my panels cannot be mounted hard to a metal case that is
grounded to mains earth. I solve that by having my power supplies in their
own metal cases which are earthed to mains earth. The resistor between 0V
and mains earth is then installed in the power supply. If the power supply
needs to go into the same case as the rest of the synth, the power supply's
own smaller cabinet is mounted using some sort of insulators, such as small
rubber shock mounts, and the 0V connection is connected to the panel/case
earth.

Ken

>Hi Mike
>
>I'm connected to the Main Earth Stud on the 240V side for the Signal
Out Ground Connection.
>
>So i should connect Signal Out Ground Connection to the Ground on the 15V
side , is that correct ?
>
>Do any of the Earth / Ground connections need to be physically connected to
the Chassis ?
>
>I'm going to keep my Signal Out Ground connection at the Power Module is it
is at the beginning point for multiple module connections.
>
>My module power connections are Daisy chained pre CGS distro boards.
>
>cheers for the help
>
>Stephen
>
>[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: Best of CGS Panel #3 Oscillator signal bleed problem

2011-10-18 by sasami@hotkey.net.au

>Hi Ken
>
>This thread has got a bit bogged down in talking about Earth Connections in
my Power Supply , sorry.
>
>Getting back to my original query...you suggested increasing the Decoupling
Caps value.
>
>We are talking about the 10uf 35V x2 and the 100n x2 on each Oscillator , yes ?

Yes. Try putting 22uF or 47uF instead of the 10uF, and add 100n across each
on the rear of the PCB.


>Also , your suggestion for the 1K 1 watt resistor for the Signal ground ;
would i install this between the 0V out of the 15V side of my Power Module
and before the Banana Jack for my signal ground ?

The signal ground and 0V need to be connected to each other directly - they
are the same thing.
The "ground" that needs to be separated from them is the mains safety earth,
which grounds things like the core of the transformer, and any metalwork
that could accidentally come into contact with a mains voltage should a wire
come loose, power switch short out, etc..

Also make sure the power wires to your modules are thick enough. There is no
need to go overboard with wire thickness, but too thin can be a problem.
Light signal wire is probably inadequate.

Ken
_______________________________________________________________________
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: Best of CGS Panel #3 Oscillator signal bleed problem

2011-10-19 by Stephen Richards

Thanks , I'll keep the thread posted about how it goes.

Stephen


________________________________
Show quoted textHide quoted text
From: "sasami@..." <sasami@...>
To: cgs_synth@yahoogroups.com
Sent: Wednesday, October 19, 2011 10:29 AM
Subject: Re: [cgs_synth] Re: Best of CGS Panel #3 Oscillator signal bleed problem



>Hi Ken
>
>This thread has got a bit bogged down in talking about Earth Connections in
my Power Supply , sorry.
>
>Getting back to my original query...you suggested increasing the Decoupling
Caps value.
>
>We are talking about the 10uf 35V x2 and the 100n x2 on each Oscillator , yes ?

Yes. Try putting 22uF or 47uF instead of the 10uF, and add 100n across each
on the rear of the PCB.

>Also , your suggestion for the 1K 1 watt resistor for the Signal ground ;
would i install this between the 0V out of the 15V side of my Power Module
and before the Banana Jack for my signal ground ?

The signal ground and 0V need to be connected to each other directly - they
are the same thing.
The "ground" that needs to be separated from them is the mains safety earth,
which grounds things like the core of the transformer, and any metalwork
that could accidentally come into contact with a mains voltage should a wire
come loose, power switch short out, etc..

Also make sure the power wires to your modules are thick enough. There is no
need to go overboard with wire thickness, but too thin can be a problem.
Light signal wire is probably inadequate.

Ken
__________________________________________________________
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: Best of CGS Panel #3 Oscillator signal bleed problem

2011-10-19 by Stephen Richards

Hi Ken

Increased the size of the decoupling caps to 22uf and 220n , it had no effect on signal bleed problem.

Would it be advisable to return these caps to their original values in this case ?

Stephen


________________________________
Show quoted textHide quoted text
From: Stephen Richards <okayjustalittle@...>
To: "cgs_synth@yahoogroups.com" <cgs_synth@yahoogroups.com>
Sent: Wednesday, October 19, 2011 1:45 PM
Subject: Re: [cgs_synth] Re: Best of CGS Panel #3 Oscillator signal bleed problem


Thanks , I'll keep the thread posted about how it goes.

Stephen


________________________________
From: "sasami@..." <sasami@...>
To: cgs_synth@yahoogroups.com
Sent: Wednesday, October 19, 2011 10:29 AM
Subject: Re: [cgs_synth] Re: Best of CGS Panel #3 Oscillator signal bleed problem



>Hi Ken
>
>This thread has got a bit bogged down in talking about Earth Connections in
my Power Supply , sorry.
>
>Getting back to my original query...you suggested increasing the Decoupling
Caps value.
>
>We are talking about the 10uf 35V x2 and the 100n x2 on each Oscillator , yes ?

Yes. Try putting 22uF or 47uF instead of the 10uF, and add 100n across each
on the rear of the PCB.

>Also , your suggestion for the 1K 1 watt resistor for the Signal ground ;
would i install this between the 0V out of the 15V side of my Power Module
and before the Banana Jack for my signal ground ?

The signal ground and 0V need to be connected to each other directly - they
are the same thing.
The "ground" that needs to be separated from them is the mains safety earth,
which grounds things like the core of the transformer, and any metalwork
that could accidentally come into contact with a mains voltage should a wire
come loose, power switch short out, etc..

Also make sure the power wires to your modules are thick enough. There is no
need to go overboard with wire thickness, but too thin can be a problem.
Light signal wire is probably inadequate.

Ken
__________________________________________________________
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: Best of CGS Panel #3 Oscillator signal bleed problem

2011-10-19 by sasami@hotkey.net.au

>Hi Ken
>
>Increased the size of the decoupling caps to 22uf and 220n , it had no
effect on signal bleed problem.
>
>Would it be advisable to return these caps to their original values in this
case ?

Yes, you may as well.

Ken


_______________________________________________________________________
Ken Stone sasami@... otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

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