RCA switch grounding

[45144]

I am planning on making a switch box with 1 RCA in and 2 RCA out. The purpose is to connect one preamp to 2 power amps. I can buy one like in the photo but would rather build it and I already have all of the parts.

Question:
Should I only switch the + signal and just connect all of the grounds together or switch both the + signal and grounds for each? Or wire it differently?

This is what I am talking about:

Thanks

 

[turk 182]

heck no transformer or opto isolated is the way to go otherwise i see you starting a new thread on ground loops...


please note that the shown device is intended to switch two inputs to one output you want things the other way around,no?

 

[45144]

heck no transformer or opto isolated is the way to go otherwise i see you starting a new thread on ground loops...


please note that the shown device is intended to switch two inputs to one output you want things the other way around,no?

It goes both ways, just an example anyway.

 

[turk 182]

sorry no the biggest fallacy is that all grounds are common....and no when it comes to splitting a signal across two inputs without isolation or a buffer it's loop city....so go ahead build a switch with common ground if you like. (apologies in advance for snarkyness)

 

[45144]

sorry no the biggest fallacy is that all grounds are common....and no when it comes to splitting a signal across two inputs without isolation or a buffer it's loop city....so go ahead build a switch with common ground if you like. (apologies in advance for snarkyness)

If that is the case then couldn't I just switch the grounds also?
The signal is not really being split, just switched.

 

[turk 182]

then yes all should be good, but if things are powered on then switching grounds can still be problematic from a noise perspective, i would still consider a buffer or repeat coils to do what your suggesting.

 

[45144]

then yes all should be good, but if things are powered on then switching grounds can still be problematic from a noise perspective, i would still consider a buffer or repeat coils to do what your suggesting.

I will never activate the switch with anything under power, too risky.

 

[turk 182]

ok then yes all's good... insuring that ground returns even to a device that's off is insurance to preventing an inadvertent loop and best practice.

 

[45144]

I have the box built, I have all of the L grounds together and the right grounds together. Should I keep the L and R star grounds separate or tie them together?

 

[turk 182]

leave them separate.

 

[forr]

I built a similar box with a stereo switch for two sournce and a 10 kOhm pot.

All the RCA bases are grounded to the chassis. I never had trouble with it.

 

[45144]

leave them separate.

That is what I did.

 

[45144]

Works like a charm, no noise no ground loops.

 

[turk 182]

nice work!!