First note: I've looked through other threads but they seemed rather off-target or unclear to me (again :o).

I'm re-building an amplifier and one of its functions is switching between sources. This is consumer-grade line level (pro grade line level is hotter).

They're practically a two way switch, but two of them in once. A little like 1-Common-2.

My question is: if Pin 2 is connected to a common (SIGNAL) ground, do I connect the switch so that if it's in the 'on' state, passing audio from Common to 1 (To Output), and when 'off' from Common to 2 (Ground)?

Reading through other threads made it clear it's technically safe to do this but is it common and how you do it? I'm afraid if I make Common the common output, and lines 1 the 'input' that runs from rca to switch, that it'll cause some distortion. If I make it go to Ground when 'off' then there's no chance of interference because ground is a shorter path.

I just want to make sure, and is this right?

As a little side note: What gauge of wire would be the best for this application?

Thanks anyhow. :)



simulate this circuit – Schematic created using CircuitLab

  • 1
    \$\begingroup\$ Can you draw a schematic of the swtich? It might make it easier to understand the question \$\endgroup\$ – Joren Vaes Aug 23 '17 at 12:54
  • \$\begingroup\$ @Alex: Your last paragraph is a shopping question and is enough to have your post closed as they are not allowed. You should remove it. There is a schematic button on the editor toolbar so please add a schematic. Also, please tell us in the comments that "I don't need cryogenically cooled wires" is a joke. \$\endgroup\$ – Transistor Aug 23 '17 at 13:16
  • \$\begingroup\$ Your schematic seems to show the inputs being shorted to ground in one switch position - that seems like it's probably not a good idea. \$\endgroup\$ – Chris Stratton Aug 23 '17 at 18:07
  • \$\begingroup\$ That's actually what I'm asking about in the question. I know Audio-sources can and are built to be able to do that. What my relevant question then is, is this the way I need to do it to switch audio signals without 'residual current'? \$\endgroup\$ – AlexianaBritmonkey Aug 23 '17 at 18:23

" What my relevant question then is, is this the way I need to do it to switch audio signals without 'residual current'? "


First, that type of switch is called DPDT - Double Pole Double Throw. Each common terminal is a pole, and each pole can switch between two throws.

A better way is to make each switch pole the output to a volume control. Then, one of the switch throws goes to the input and one goes to ground. In this way, when an input source is "turned off", the input to the volume control and all downstream circuits is not left floating, as an antenna waiting to pick up noise, nearby ratio stations, other input signals, etc. Instead, it is grounded to eliminate random noise pickup, while the audio input is left open circuit so you are not loading the source with a short circuit.

  • \$\begingroup\$ Hmm, sorry, but I don't really understand that.. yet. Can you somehow simplify it with a schematic? \$\endgroup\$ – AlexianaBritmonkey Aug 24 '17 at 6:39

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