Gibson Falcon RVT-19

[andyjazz]

I've had this amp for awhile. thinking about buying some new filter caps. Is there some company that would sell a set like you'll find with the popular Fenders?

[Justin Thomas]

Not likely. Just checked three fairly popular sites, nada. Post a schematic? It's very possible that a comparable Fender set would work. Even if the values aren't perfect, caps had ratings like -20/+80 back when.

Justin

[andyjazz]

There is always the schematic from the tube Amp book

Trying to figure out how to post the schematic

[xtian]

Just go to tubesandmore.com and order exactly what you need. Do you need help interpreting the schematic?

[Justin Thomas]

I'd think 5 x 20 or 22uF @450V would do it... any brand will do. I like F&T, not too expensive, classy-looking, not overly big or overpriced like Sprague Atoms.

Were you going to do the cathode bypass caps, too?

Justin

Edit: tubesandmore.com has 10uF/500V Illinois caps for $3.55. Not too shabby.

[g1]

With all the variants of Gibson models, it would be best to make sure what you have in your amp matches up with what is shown on the schematic.
In case of discrepancy, replace with what the labelled value is in the amp itself.

[Enzo]

With Gibsons, I always think of the schematic as more of a suggestion than documentation. Cap values are not all that critical, so if you need a 20-20-20-10, and all you can find is a 20-20-20-20, it will do fine.

[andyjazz]

I had a house fire on 1/30/15 and my entire workshop became literally toast. Lost all my guitars. Lost a lot. But my '62 Falcon and a '64 Fender Pro made it through! I've finally gotten around to setting up a little shop space but a lot has changed...........I just didn't want to do anything with amps or electronics for a long time. Dipping my toes back in the water I guess. I'm going to pull the Falcon apart tomorrow and see exactly what is going on in there - I replaced the output transformer about 5 years ago. I put a CannabisRex speaker in it last year and that has made a big improvement - the old stock Jensen was a goner. I think I remember replacing a few components here and there. Just thinking this time to buy some nice new good quality high V caps and see what that does to brighten up the tone. It has become a bit murky. Isn't there some other thing about changing the caps on the tone wiper to lessen the high freq. tone dump that circuit is known for? The thing has been a real champ tho. Never been finicky like some old amps. thanks for your help guys!

[andyjazz]

Ok so finally had time to take apart the old Falcon. Posted a couple of photos here. I've ordered some caps: 3 450V 10u's and a 450V 20u. I don't think i'll mess with the old Sprague's on the tremolo circuit. The tremolo is working fine and I don't see why to bother. There is the curious little cap/res arrangement on the Bass/Treble (Tone) knob. This is what I referred to before. I've seen some suggestions to cut out this cap/res unit (Which I guess was Gibson's way of trying to be a high-pass filter) and just connect the vol and tone pot like normal - like it's just a treble knob. Haven't done anything yet, in fact I'm going to put it back together and play a gig tonight, wait for the caps to come in before i do anything.


image #341 shows the cap/res unit off the "bass" side of the tone knob.

Your thoughts?

[Daver]

That cap and resistor aren't in parallel and not a high pass filter "unit". They connect to two different lugs on the pot. The resistor doesn't look like it's on the schematic. The cap is part of the tone control. If you remove it, it won't work properly.

[andyjazz]

Ok here's some pics of the finished job. I used some copper plumbing straps for cap holders. Looks kinda heavy duty but.....I don't care, it fucking works. As Daver pointed out the one resistor on that tone leg isn't on the schematic. I took it out just to see if it would change a little of how this tone pot is functioning. Didn't make a whole lot of difference. The new high V caps didn't do a whole lot to change the way this amp sounds either. These old Gibsons are kinda cute and funky but they'll never be a Deluxe or a Princeton. Anyway, I've had enough dorking around with this thing. I DO like the tremolo unit - it's real silky smooth. The amp sounds great when paired with a Pro Jr. in stereo but I think at some point I might just sell it and get a Deluxe. $70 - $80 of parts and a bunch of time and what did I get? Well I know now that I should quit being a musician and become a drummer![ATTACH=CONFIG]44110[ATTACH=CONFIG]44111

[Leo_Gnardo]

I used some copper plumbing straps for cap holders. Looks kinda heavy duty but...

I like those copper straps, very kool makes it look like metal sculpture!

The small electrolytic cathode bypass caps in the preamp are often failed by now - replace them if you already haven't & you may find your Gibson can roar a bit.

[Randall]

Yeah, if you are going to the trouble to replace the filter caps, you should replace the cathode caps. They have more to do with tone than the filter caps.