[sdiy] mixer

[Glen]

At 11:11 AM 11/2/01 , harry wrote:

>The self-noise of the resistor is proportional to resistance, so the bigger 
>we make the resistor, the worse the noise gets.
>
>The trade is to use the lowest input resistor we can stand, that does not 
>interfere with the driving stage.
>
>H^) harry

Thanks Harry. So I was basically correct? 

If one is only mixing typical, unbalanced line-level equipment, the noise can
be reduced by using a lower input resistance on the mixer. Instead of 47K, I
would probably use 5K, which I admit sounds extreme, but I'm very fussy about
noise. Remember, this assumes that the input will always be feed with an
unbalanced, line-level signal. If you need to feed this same input with things
like electric guitars, or low-impedance balanced mics, then you will need an
appropriate preamp to insert between the signal source and the mixing input.
The original post mentioned nothing about guitars or microphones, but only
line-level devices like synths and effects units. My suggestion should work
well for those devices.

Later,
Glen