Using tubes in place of JFET's in an Citrus Graphic mkii build?

[dwrockdoctor]

Hi everyone!

I am in the process of building an Orange Citrus mkii pedal that is a jfet based emulation on the Orange OR120 preamp. I was wondering how much change would be in order to place two 12AX7's in place of the four JFET's in the circuit?

From some online searches I gathered that the 12AX7's would work best being powered by at least 100V so I would have to change all the components to a much higher voltage rating and find a relevant power supply. (And obviously take much higher precautions with safety!).

Is it simply a matter of converting the tubes triode connection points to the relevant spots where the JFET would usually connect and upping the voltage rating on all components?

Am I a hack that is in way over his head? (Most probably yes!)

Anyways, thanks for taking the time to entertain my whimsy

[Luke51411]

Why not just build an amp if you are going that route? You would have to build some sort of power section to get to that voltage, I think the tubes are biased differently so some of the resistor values would be different. At that point I'd think you would just go off of the original amp schematic. GrindcustomsFX has done something similar in porting an amp to a pedal format but it will take a lot of research on your part. This isn't something that can just be easily plugged in.
Here is what Grind has:
https://dl.dropboxusercontent.com/u/28586266/GCFX%20Build%20Docs/CleggsterPSU.pdf
https://dl.dropboxusercontent.com/u/28586266/GCFX%20Build%20Docs/STM800BuildDoc.pdf

Please note, extreme caution must be used when dealing with high voltage.

[dwrockdoctor]

Kind of what I was expecting, thanks Luke!

I wouldn't mind trying the citrus graphic through the power section of my ceriatone marshall superbass clone by going into the return on its effects loop. Might have to use my SHO clone between the citrus and ceriatone power section to drive it all properly. It'll interesting to see the results either way.

One day I will get an OR120 based amp, it's on my list of gear to own bucket list.

[Luke51411]

My answer is just pretty general, I don't know all the specifics and good bits of knowledge but I'm sure one of the really knowledgeable people around here will chime in with more info. And by power section I meant the circuit that is actually going to provide power (voltage) to the tubes not the power amp section that drives the speaker.

[dwrockdoctor]

Not to necropost but I thought I'd wrap up this thread to let anyone interested know that I ended up diving in the deep end and built an entire OR120 clone amp from a weber 6O100 kit.

It was a huge learning curve and a bit of trouble shooting but I finished it and it sounds amazing, everything I've wanted in a gain amp, no fuzz pedals required!

In the middle of a matamp GT120 build right now, just waiting on parts.

Next on my list is to design a citrus orange micro amp, maybe using a class D power amp section.

To think I wouldn't of built the OR120 if it wasn't for hearing the potential once I'd finished and heard the orange citrus pedal!

[J0K3RX]

Cool man!! Pics/demos... Please?