Concert Slave Question

[Isaac]

Anyone know the input impedance of the first generation, silver and black faced Concert Slave?

I'm looking your way, Joe...

[Soundfur]

I think it was 4, if you used the 4x12 cabinet, 2, if you used 2 cabinets.

[Isaac]

That's the minimum output impedance. I'm looking for the input impedance. That's the impedance a signal sees going into the amp. 10K ohms is a fairly common figure, but input impedances can go as high as 1M ohm.

[JoeArthur]

Hmm... never seen it "specked".

I can give you a quick and dirty guesstimate from the schematic - with the sensitivity control down (zero) it would be 100K (simply the value of the linear pot).... it's roughly 75K feeding into the first amp stage, so at max sensitivity it would be the parallel combination - roughly 40K.

That would be a ballpark.

Why does it matter... you got something sneaky planned? 

[Isaac]

I'm planning on making myself a passive low pass filter and using it for a sub amp. I figure that I'll be okay as long as the input impedance is over 10K.

Thanks!