a/b preamp switch

[j.d.roost]

Hello all.
I am building a a/b stereo preamp switch box (four inputs two outs) to switch my gsp2101 and my mesa studio pre. into my 2:90 power amp.
I will be using a 4pdt relay and switching it with BC557 transistor (latching switch controlled).

My question is..
Should I switch the non used preamp outputs to "open" or should I ground them with a resistor (putting a slight load on those outputs). Both 2101 and mesa inputs will be "hot" all of the time (y cable).
Does it harm a preamp if there is input signal and no output?
Does it harm a preamp to load it with a resistor and not a power amp input?
Also what value resistor do you think would work best?
Thanks for the help.

[j.d.roost]

Built it last night with the open (open on relay) preamp inputs being switched through a 50 Ohm to ground. Works good so far and I get zero switching noise.
Again if I am hurting anything on the preamps by doing this please let me know.
Thanks.

[Steve Conner]

Don't worry about it, the open-circuit thing is only a problem with speaker outputs of power amps.

[Enzo]

If you have no problem, then you have no problem.

The reason one would put a grounding contact on the output of the unused channel is so there is no high level signal flying around to be picked up as crosstalk. You wouldn't want to hear the distortion channel in the background while playing on the clean.