sorry for this, but I'm on this build and I want to make it "as simple as possible but not more".
My source-selection will be a nice, simple (swiss 🙂 ) selector-switch. Should I make it a 4-poles switch, and switch the grounds too, or is it sufficient to only switch the signal and thus use a 2-pole switch?
thanks!
david
My source-selection will be a nice, simple (swiss 🙂 ) selector-switch. Should I make it a 4-poles switch, and switch the grounds too, or is it sufficient to only switch the signal and thus use a 2-pole switch?
thanks!
david
If your input jack grounds are connected to a grounded chasis ( very common ) then theres no point to switch the grounds, there already all joined, otherwise you have a choice, I would still switch only the hots to get rid of one contact in the signal path. Dirty switch contacts are a common fail point in older gear.
Hi David!
The rotary switch on my input selector box does not switch ground wires, only the signal wires.
The input and output grounds are commoned and unswitched.
P.S. This is a commercial switch box (from Maplin when its stores were open!).
The rotary switch on my input selector box does not switch ground wires, only the signal wires.
The input and output grounds are commoned and unswitched.
P.S. This is a commercial switch box (from Maplin when its stores were open!).
Switching GND as well can be done as no connection will be to the other inputs GND which is positive. However chances are likely that a small click can be heard because of GND potential differences. This can be solved by temporarily shorting outputs to GND by means of muting contacts or a relay.
If you don't want the added hassle of a relay then you could use a let's say 1 kOhm resistor to still have reference to GND. When the right input is chosen then the resistor is shorted. No clicks and separated GND from each input.
BTW input connectors GND is rarely connected to chassis GND directly as usually they are mounted isolated from chassis. GND connection is made elsewhere.
If you don't want the added hassle of a relay then you could use a let's say 1 kOhm resistor to still have reference to GND. When the right input is chosen then the resistor is shorted. No clicks and separated GND from each input.
BTW input connectors GND is rarely connected to chassis GND directly as usually they are mounted isolated from chassis. GND connection is made elsewhere.
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On non-double insulation devices (mostly PA gear) GND is connected also elsewhere to the PE wire. So GND is indeed connected to the chassis.
Not directly to the metal chassis as stated. Please check and see that insulated connectors are used (for a reason).
GND as in signal ground. GND can be connected to PE but this is not always so. It can also be referred to PE ("lifted"). No connection of GND to PE at all and only chassis connected to PE for safety is also possible.
GND as in signal ground. GND can be connected to PE but this is not always so. It can also be referred to PE ("lifted"). No connection of GND to PE at all and only chassis connected to PE for safety is also possible.
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No point I think - also if you do switch grounds too, you must ensure the switches used guarantee the grounds close first and break last, otherwise you'll get ear-splitting transients on switching. Such switches are specialized and rare.
However you can arrange to switch grounds but use a 100 ohm resistor across the ground contacts to lift ground enough to break ground loops, but prevent huge transients if the source is floating electrically. Not sure this would be useful except in some rare situations with ground loop issues.
This can matter if you switch often. If you'll switch it once (and you may do it turned off) then thats ok.
Hi jean-paul + mark tillotson
Thanks for the hints. I'm trying to get a picture, it's a bit over my head, so please excuse my banal questions.
- resistor (1K / 100r): resistor before entry points of the switch?
- close grounds first: Like the first deck for signal "break before make" (non-shorting), and the second deck "make before brake" (shorting) for the ground)?
thanks!
david
Thanks for the hints. I'm trying to get a picture, it's a bit over my head, so please excuse my banal questions.
- resistor (1K / 100r): resistor before entry points of the switch?
- close grounds first: Like the first deck for signal "break before make" (non-shorting), and the second deck "make before brake" (shorting) for the ground)?
thanks!
david