Footswitch tone

[slippingglimpser]

So...  Can anyone with an rca reverb/tremelo footswitch do a little experiment for me?  If you have your footswitch hooked up to your Sunn, and the reverb switched off, does your reverb knob still change your guitar tone when moved from 0 to 9?  I have a 190L, and I made my own footswitch for it so that COULD be my problem.  But it works perfectly otherwise so I'm suspect.  Well if anyone could tell me how their setup compares (or if anyone just has a good idea of what's going on), thanks.

[JoeArthur]

It is possible for this to happen, due to loading of the reverb input to the power amp to ground when the reverb is off... and I believe that the 190L also has the "collector pot" reverb level control as most of the Sunn tube amps.

[slippingglimpser]

It is possible for what to happen?  What I'd like to know is:  Is it SUPPOSED to happen?  It's not exactly a desirable feature to have.  If this helps to know what I'm talking about:  Specifically, the tone changes just the way the reverb would normally change it: harsher, muddy, and trebbly.  It sounds just like the reverb is on, only there's no echo.  If anyone could just tell me wheather this does or doesn't happen to them, thanks, 'cause then I'll know if it's my amp or my footswitch.

[JoeArthur]

My point... in most amps that have reverb, especially the early Sunn versions, the reverb on-off footswitching function will affect the "straight" sound when they are footswitched off... and it will change depending on the position of the reverb control.  Turn the reverb control full up and the sound will be less muddy when off - but it will probably be too much reverb when it is switched on.  

This is "normal" based on the circuit - as the circuit is not entirely switched out of the signal path - just the reverb input signal.  Most amps don't provide a complete isolation of the reverb mixing when switched off... as it would cost too much.

The extra loading of effects circuitry (including but not limited to reverb) may or may not be noticible - it all depends on individual preference, and circumstance.  In most "performance" situations, no one will care - but if you are practicing alone... you will notice it more.