anyone ever thought/modded a regular sunn head into one of the pa heads?

[cosmic erosion]

I own a coliseum pa and owned a studio pa. Our drummer, who also plays guitar, just picked a solarus and while he loves it, wishes it breathed fire like my coliseum. We got to talking and was wondering since almost the 2 and 4 power tube heads are almost identical in circuit, could you mod the preamp stage to turn it into a more flexible studio pa head? How difficult would it be if you could? I miss my studio pa head at times and since the pa heads rarely come up, itd be nice to snag a sceptre or solarus and mod it into one. Thanks!

[loudthud]

It can be done but here are the problems.

For all four channels, you would have to add one preamp tube. If you can get by with just two channels, you won't need the extra tube.

Unlike most vintage amps, Sunn amps have a wiring harness like an old Tektronix oscilloscope. There are no layout drawings available for Sunn amps that show which wire goes where. This is a giant pain in the a** because you have to account for every wire.

Without the Reverb and Tremolo there will be a dozen or so extra wires in the wiring harness. To remove the extra wires, you will have to cut the harness apart or just cut the wires short and leave them. Kind of makes a mess inside the amp.

The one good thing is that the Reverb/Tremolo board can be removed. That will free up space for a filter cap board. You really don't want to use the exsisting filter cap or the really expensive replacements.

The bottom line is that it's probably easier to just gut the amp and rewire the whole thing. If you are going to do that, why not change the circuit to something else. Maybe a Fender Bassman 5F6A or a 60W Model T. This is not a job for the average hobby tinkerer. It requires a well planned layout for terminal strips or fabrication of eyelet or turret boards.

[cosmic erosion]

Thanks for the reply! We were hoping to just change the first input into a more pa style one where if you crank the head, it would break up like a cranked studio pa, but with the added bonus of having a mid control and possibly trem and reverb. Seems it's not as easy as we thought.

[loudthud]

Just get some kind of overdrive pedal and be done with it.

[cosmic erosion]

He's def got enough fuzz pedals. I def went through enough of them when I had my model t. Nothing quite overdrives like the tube pa heads. I always get asked what fuuz or od I'm running and noone believes its just the head. It goes from clean to mean with just the volume knob on my guitar. I appreciate all info tho.