less treble on gibson ga-17rvt

[cshsfg]

i've had an early 60s era ga-17rvt for about a month now. it's a nice little amp, but my main issue with it is that it's ear-shatteringly bright. i can really only use my neck pickups with it, because everything else ice-picks big time.

i saw on the schematic that it's got a t-filter right before where it sends the signal to the reverb circuit, and i've been assuming that that's the main culprit. at first i was thinking that i could just bypass it, but i think that would increase the gain, which i don't really want, honestly. it's a great clean amp, and i want to keep it that way.

would the t-filter actually be responsible for the brightness, or is it something else? how could i lower the treble without increasing the gain?

TIA

[Tubenit]

coupling cap

I don't think it's the T-filter causing the treble.

Try changing C2 (coupling cap after 1st gain stage) from a .001 to a .0047 or .01.

Your ears will have to tell you whether that adds too much gain. I would not think that it will.

The original 10" speaker is pretty tinny sounding. An inexpensive speaker that may sound good with it is Emminence Ragin Cajun.

With respect, Tubenit

[cbarrow7625]

I agree with trying to change C2 first but if that doesn't get the job done, the next best candidate is C3 (around the T filter). Try putting a little bit of resistance in series with that cap. It should mellow it out a bit. You could also try changing the cap out with a new one of the same value. Silver Mica? Poly cap? I usually find that small poly caps are too mellow for a guitar circuit but they might be just what you need.

If all else fails try putting a 50-250pf cap to ground across the volume pot to mellow things out a little bit.

Whoa! I just realized that C5 (cathode bypass cap in the second stage) is only 0.1uF. Maybe try increasing that FIRST to 5-25uF. That should mellow things out a bit, especially if that 0.1uF is currently a ceramic cap.

[cshsfg]

this amp doesn't have a speaker. one of its previous owners decided to convert it to a head...





(the original ot died, as you can see...although i would've changed it anyway, since it was even smaller than the reverb transformer)

i don't have any close-ups of the actual "workmanship", but he basically just butchered the original cab.

but yeah, when i get the time i'll change out that one cathode bypass cap. think i've got a 25u around...and i might change that first cap and then see about making it switchable, because earlier today i was seeing how hard i could push the amp with different distortion/boost/fuzz pedals and the brightness is actually useful, it really helps it to cut through.