Shorting the secondaries provides a very smooth mute with no switch-pop noise. However, is this safe for the device connected to my input? The device in question is a Shure Wireless Receiver with a 100Ω output impedance.
Yes there is a transformer between device and this preamp. Galvanic isolation is nice. If you are worried you could use 100 Ohm resistors from R2 and R4 to the mute switch contacts.
Still the Shure Wireless Receiver should have power on/off muting by means of a tiny relay shorting its outputs to GND.
Still the Shure Wireless Receiver should have power on/off muting by means of a tiny relay shorting its outputs to GND.
Short the output, not the input, as long as there is a finite output impedance. That way it’s buffered from the source, and you also lose all the intermediate noise.
Or short after R2/4.
Or short after R2/4.
Maybe you can give info why you want to mute inputs. Not because of power on/off plops of sources I see.
If it is about just muting why not mute at the primary side of the transformer?
If it is about just muting why not mute at the primary side of the transformer?
It's an input selector. Six channels of Shure Wireless (for guitar) should be selectable with individual mute switches and summed to one output.
Can be done at each input with micro relays controlled by either switches or controlled electronically. Before the transformer or after the transformer. I would not use wiring from sensitive circuits to switches at all, keep connections as short as possible and leave the opamp circuit in peace. Hence the relays.
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