12AX7 output impedance - 2 x loads...

[diddymix]

Hi folks,

I was hoping anyone with technical knowledge of circuits and tube design could give me some pointers on what I'm doing, and if theres anything to watch out for.. much appreciated for your reading time.. Basically I'm about to finish rewiring a circuit in my amp, so that I have a newly arranged OD stage, and another clean option.. the only thing is, now the only route I could use (with the channel switching).. means that V1a plate now feeds two tubes instead of the one route that was stock.. so the OD stage basically means that V1 feeds (V2 + V3) even when im on the clean channel V1... so there are now 2 x 12ax7 loads. The channel switching just mutes the OD stage output so either channel feeds the PI. Is there an issue with driving 2 separate stages with one 12ax7??

I guess my question is, Is there an issue with driving 2 separate stages with one 12ax7?? is there anyway this is a bad idea in terms of the load impedance, and how does it change, does it half or double up?? Would this potentially change the tone/volume of that channel vs my stock V1 channel (1x load output)??

Thanks guys

[nworbetan]

Nobody is going to be able to give you a definite answer without a schematic.

In theory, yes, it's possible to connect the output of one tube to the input of any number of other tubes. The details are what matters, and we'll need to see a schematic.

[Stevem]

There are no special things to and or calculate in regards to what you want to implement.

Go take a look the schematic for example of the vibrato channel in a Fender Bandmaster reverb amp, or any Blackface or silverface Fender amp with reverb, as they all have a circuit in which the plate of 1 12ax7 is cap coupled to the grid of two other tubes, one 12ax7 and one 12at7.