Preamp source selection using relays question.

[sjalloq]

Hi there,

I'm building a preamp and will be using relays to switch the inputs. Are there any best practices I should follow to minimise input crosstalk? Grounding etc?

I've seen designs that use a large resistor to signal ground on each signal input and others that don't.

Thanks.

[nigelwright7557]

If high impedance inputs are left floating they can pick up hum and noise.

[Jan Dupont]

See this thread;
preamp question

[AndrewT]

try searching the Forum.
This has been discussed many times.

[sjalloq]

Andrew, you are a very knowledgeable chap, but you aren't half a rude so and so some times. Was there any real need to post that?

I did search. Just for the wrong terms it seems. I actually spent 30 mins trawling through non-relevant stuff before posting. But thanks for your helpful input in any case.

[Juergen Knoop]

Originally posted by sjalloq


I've seen designs that use a large resistor to signal ground on each signal input and others that don't.

that's a usual precaution against dc over the relay contact, making switching 'pop- or clickless'. Otherwise a capacitor coupled floating source would charge the coupling cap over the contact.
regards