Internally jumpered channels on a plexi

[Silvio55]

Hi folks! I'm starting my next proyect, a 50 watt plexi. I would like to keep it as simple as possible (less room for mistakes ), and I was considering the idea of making it with just one input jack, and the channels internally jumpered at the tube socket. What I want to know is if I put the volume of on channel down to zero, would it sound the same (or almost the same) as if I was plugged to just the other channel?
Thanks!

Silvio

[pdf64]

I'm never quite sure which exact circuit is meant when people refer to a plexi.
I think a few different models were produced with the plexi panel, some will have more channel interactions than others.
With 2 input jack sockets, you can have either / or/ both, see Combined Auto-mix / Independent Inputs For 2 Channel Amp Photo by pdf64 | Photobucket
Pete

[Silvio55]

Sorry, I mean the early 70's 1987 Lead 50 watt, split cathodes, the mixer resistors are 470k, there are several variations of this circuit, but the changes are minor. Thanks pdf, I knew that schem for two inputs mix, but I was wondering if the amp would sound the same with the channels jumpered and one volume at zero, i would like to have just one input.

[pdf64]

With the 1987, the bright channel 470k mixer resistor has a 470pF bypass cap.
So with nothing plugged into the bright channel, its volume control setting causes the normal channel to go from muffled to normal as it's increased.
So, you will lose some tone flavours but it's probably not a big deal.
Pete

[Silvio55]

Ok! so the difference is bigger with the normal channel, I know there´s always some interaction between the channels, but that doesn´t bother me much, I´m more a treble channel guy, in fact I´m planning to mod the normal channel and make it more like the treble channel of earlier plexis.