Modified Deluxe questions for beginner

[dragonbat13]

I want to build an amp off of a deluxe 5e3 Schematic. I want to use the stage for the mic volume and input for a gain stage with a gain control. I also want a presence control. I would have a volume, tone, gain and presence knob. How easy would this be? Is this even possible? Thanks for your help.

[Alexo]

Well a presence control is usually a by-product of a negative feedback loop and the 5E3 doesn't have a negative feedback loop, you could add one but it would really change the character of the amp, it might also be a bit more complicated to implement in the cathodyne phase inverter that the 5E3 uses.

It sounds like you want to run your preamp stages in series rather than parallel...? That is not too difficult, just disconnect the top lug of one volume pot from the phase inverter input and the tone control and connect it to the input of the other tube in place of it's input scheme (68K/1M resistors).

BUT, I always say this and I think it is especially important if you are a newbie - build the amp stock first and THEN do your mods! It will be infinitely easier to troubleshoot and you will have a better understanding of the effect of your mods.

[dragonbat13]

I had intended to build the amp to the stock schematic first. I will probably leave the presence out. If I were to wire the stages in series as you suggest I wouldn't have controll over the amount of gain of the first stage if I follow you correctly. At least not with a Pot. How difficult would this be to do?

[rfgordon]

If you want to convert the 5E3 to a KILLER amp, use the wire the two 12AX7s per the Blues Express schematics in the Trainwreck files section. I would add a choke and an extra 33mF filter cap, but that's not imperative. You could then have volume, tone and a free control hole--you could put a presence control there, or, for more control over gain and dynamics, change the grid load resistor of V2A to a 22k in series with a 100k pot. I've built such a beast, and trust me--it kills. You can build the whole thing on a 5E3 board.