bf pr boomy tone

[scole]

my pr build has a really warm tone almost woofy. i need to put the tone on 8 to get it normal sounding. i used a 40,20,20,20 cap can. i wonder if i change the 40 to 20 will that brighten up the tone?

[txstrat]

I wouldn't think so. Since the filter caps are intended to smooth out the ripple of the B+ I think they wouldn't affect the tone too much.
Have you checked the values of the tone stack and the cathode resistors? Tubes? Cables? Don't laugh - tone pot on the guitar?

[Five_E35]

Even with an original, a Fender BF tone stack needs to be at 7-8 treble and 3-5 bass to get classic Fender sound, especially on the smaller ones. Back in the day, running the treble on 9-10 on the big BF amps was common for gigs. They aren't HiFi amps with flat frequency response when everything is at 6. I don't think they'll even produce flat response at any setting.

With humbuckers smaller BF amps also need the bass turned down even more to avoid flab, they also get darker sounding if biased really hot, as the higher idle current pulls down the plate voltage on the preamp tubes. BF amps use a 30% audio taper treble pot. If you have a 10% in there, you'll need to turn it up more.

[Jag]

You could try a smaller coupling cap before the PI, say .01uf or even .005uf. Or you could try changing the bypass cap on the first or second stage to 5uf or 1uf.