'67 Fender Bandmaster--worth a shot for harp?

[sgfable]

I've got an injured '67 Bandmaster that's been gathering dust for years. Wondering if there's any opinions on whether or not it could make a decent harp amp with a few tweaks. I think its going to need a cap job and possibly a new transformer--some years ago I replaced the indicator light with a defective bulb an caused an apparent dead short; the wires coming out of the main transformer are melted which I assume is a bad sign. Any ideas?

[r0bo01]

i just recapped my bf bandmaster who might be a contemporary of yours - bought used in '71. http://music-electronics-forum.com/t13658/.
kit cost $69.99 from vintage amp south (ebay store), although u might be able to find cheaper at local electronic store.
schem (ab763) shows pilot light powered off heater winding of pwr trans. do the tubes light up (assume no short now)? if not, pt is in trouble i think. I was looking at them fearing the worst for mine - $180 seemed ballpark.
so, some bucks worst case...

[MWJB]

It can make a great harp amp. Either run it into 4x10" at 16ohms each in parallel (4ohms overall) or fit a 2ohm output transformer and run it with 4x10" at 8ohms each in parallel.

I'd use a larger preamp dropping resistor (56K to 82K at 3W insead of 10K stock?) in the power supply, look for 170vdc (+/-10v) on the plates of the 12AX7 in V1. Increase input load at Normal/Vibrato #1 input to 5.6Meg from 1Meg. Use 100uf bypass caps at V1 & V2 pins 3 & 8. Use 0.1uf coupling caps at V1 & V2 pins 6 and feeding pin 2 of the PI tube.

Experiment with a 1uf cap bypassing the NFB load resistor (100 ohms), acts like a presence.

If your amp has a 0.047uf middle caps, replace these with 0.022uf.

Rebias to between 8-15mA per tube if going 4x10", I'd use Sovtek 5881 WXT.

If you go with 2x10" then try 30-35mA per tube, some Phillips 6L6WGB would be cool, or maybe SED 6L6GC.

I like the JJECC83 for preamp tubes, be sure to compare a ECC83/12AX7 with the 12AT7 in the PI & go with what you like the sound of best.

Go for a PT that will give you between >470v (360-0-360VAC) and 510vdc (375-0-375VAC) at the power tube plates when biased up, I'd go with the higher voltage for best volume & punch.

[sgfable]

Thanks all,

Used that same VIntage Amps South ebay store to pick up a new power tranny. Hooked it up and everything came right on line. Pots and jacks need some cleaning, but otherwise the amp sings like a drunken angel. . .Thanks for all the advice on the mods/cabs. Will start messing around when I get some more time.