Sluckey November Amp Shared Input

[mwelch55]

I was looking at Sluckey's November Amp and noticed that he tied the input of two triodes together and then mixed them together into the next stage.
I am building a two-channel amp (second schematic) and I wondered how it would work to tie the inputs together instead of switching?  I was hoping to do the channel switching right before the power amp.

[shooter]

the quick n not verified way;


once I did this "Plexi-ish", I never looked back, the last 4 amps have had this "style" preamp into a DCCF, TS, (possibly a driver) then PA
simple, easy to voice each section

[mwelch55]

Thanks for the reply.  That looks like it would work, but with the extra gain stage, the cathode follower, and the Marshall tone stack, it would sound more like a Marshall than a Fender.  I wanted a Fender Tweed sound for that channel. Also, I wanted each preamp to be completely separate, not blended.

If the two inputs were connected as in my schematic, would the amount of signal to each of them be reduced by one half?

Mike

[SEL49]

If the two inputs were connected as in my schematic, would the amount of signal to each of them be reduced by one half?

no

[passaloutre]

You could use a DPDT to switch the channel inputs on tandem, but I don’t think the unused channel is going to load down your input signal enough to matter.

[kagliostro]

You can tie together the input but not the output, there, as you draw, you must use a switch

That is because each triode in the schematic works as an inverting gain stage with the exception of the CF

In one branch of your circuit you have 2 triodes so the output signal is in phase with the input signal

On the other branch you have 3 triodes followed by a CF, as the CF isn't an inverting gain stage, at the end of this gain chain you find a signal that is inverted respect the input

It is clare that to connect in parallel the exit of the two channels won't work correctly

Franco