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Gibson Falcon (GA-19RVT)

Discussion in 'Amp Central Station' started by Jack Clayton, Jul 15, 2019.

  1. dreadfulsnake

    dreadfulsnake TDPRI Member

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    I would not mod the amp or replace parts just because they're old*. You've already said you'd pit it against any Fender. Count your blessings - you've scored a great amp! Start with basic maintenance and proceed with repairs if needed. Clean and re-tension all of the tube sockets. Clean the pots. Tighten screws. Reheat any cold solder joints you see. That might be all that it needs. Enjoy the tone!

    * Couple of caveats: I'd consider installing a three prong power plug. And I'd probably replace the power supply electrolytic caps if they were 40+ years old.
     
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  2. Jack Clayton

    Jack Clayton Tele-Holic

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    The previous owner already did the three prong mod, so that's taken care of. I think the only thing that needs to be addressed other than a few new tubes, and maybe a cap job, is a tiny bit of speaker buzz. I'm hoping it's just a few loose baffle screws.
     
  3. arcanek

    arcanek TDPRI Member

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    Those are mica capacitors. The 'domino dots' are the color coded capacitance values. Haven't seen one of those in decades. I had a few from an old grab bag purchase from back in the 70s, from Olsen Electronics. I'd definitely look at replacing that with a new film capacitor. You should be able to find a polystyrene cap to match the value, which sound better, but an epoxy one is probably a better choice if if gets hot. Should be in the picofarad range.
     
  4. gbart14

    gbart14 TDPRI Member

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    Your GA is a great sounding amp and the reverb and trem are unreal. I would not alter anything in it. I am fortunate to have an original '63 that my buddy had since new. Since I got that one, I have found two GA77's a 1959 and 1961. Both tweed and neither have reverb or trem. The 59 I found for $350 and invested about $250 into it including a reconed original 15" speaker. It is very hard to beat the tone and overall sound quality from these amps at any price. The '61 I bought completely restored with very nicely done new tweed. Since it was restored, I keep my original 59 at home and gig with the restored one. Cannot beat it in my book. Good find.
     
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  5. cap47

    cap47 Tele-Holic

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    Don't start throwing out the old tubes in most cases they are better than new tubes! Like others have said clean pots, jacks and such and check Electrolytics. Get rid of the old 2 prong cord. Do not mod!
     
  6. 11 Gauge

    11 Gauge Doctor of Teleocity

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    The ones in my cousin's that I cleaned up all tested out good. Some were probably original tubes. IIRC, that one was a '66.
     
  7. Wally

    Wally Telefied Ad Free Member

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    +1 on just not throwing the old tubes outs in effect they could very well perform better in the circuit than would new ones.
    Re: testing....even the best testers will not tell one how a tube will perform in a circuit. The only ‘tester’ that will do that is an amplifier.
     
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  8. Jack Clayton

    Jack Clayton Tele-Holic

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    I certainly hope you guys are right. This amp sounds fabulous as is, and I'd be surprised if a set of JJ's would do it justice. There are definitely some tonal issues, but I'm crossing my fingers that the tubes aren't the issue.
     
  9. Wally

    Wally Telefied Ad Free Member

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    Until the amp electrolytics are replaced and good general service is done, one really doesn’t know what an amp is, ime....no matter how good one thinks it sounds before.
     
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  10. tombob

    tombob Tele-Holic

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    I like those amps. I would just make sure it’s had a cap job and the tubes are good and play it.
    I’ve got a “whiteface” ga15rvt that was the first amp I bought. The whiteface models have some weird tonestack, I believe they call it a Twin T that doesn’t sound good to me. I modded mine a few years ago and made a great amp but it’s a el84. The 6v6 ones are great stock in my opinion.
     
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  11. King Fan

    King Fan Poster Extraordinaire Ad Free Member

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    These threads get a bit tangled as they grow. For example, the OP said it has a 3-prong power cord.

    And Jack, it sounds like you're listening to the good advice here, which I always admire, but as the thread grows, let's review the most vital items: *Don't* throw out working tubes, definitely don't replace working transformers (bye-bye resale value), and don't say *maybe* you'll replace electrolytic capacitors. If the filter caps go, they can take your PT (bye-bye again), and as @Wally says (always listen to Wally) until proven otherwise, any and all tonal issues *may* be due to aging electrolytics.

    As an amazing detail, that Guitologist video (nice one, @rghill ) seems to ID the 'square domino shaped component' that various people here discuss, the one that sucks tone in some of these Gibson circuits. It seems it wasn't a domino cap after all, it was Gibson's whole 'tone sucking network' (probably not their name for it!) built into a little square component by Sprague. You can see it in the video around the 30:00 mark, and he shows its part number and schematic. It might be worth getting rid of *that* (if one's in there). But he also says they built out the network with individual components before Sprague started making these, so a sharp eye on the network's schematic vs. the amp is in order.

    TSN.jpg
     
  12. Mike Eskimo

    Mike Eskimo Telefied Ad Free Member

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    Everyone need two brown bark tolex GA-19RVT’s

    One stock for it’s weird clean original thing.

    And one modded.

    Dean Zink played through one that he had done (“this amp is an example of what happens when guys that are into hi-fi help design a circuit...”) and it was very crunchy and juicy and fantastic.
     
  13. King Fan

    King Fan Poster Extraordinaire Ad Free Member

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    FWIW, re general amp service steps you may need to do, Doug Hoffman has some good details. The input jack resistance figures are Fender-specific, but for things like if and how you want to clean pots and jacks, and re-tension sockets, it's good stuff.

    http://el34world.com/charts/fenderservice2.htm

    Also, on that page he links to the other pages in that section on general amp service -- worth a look for anyone bringing an old amp into service.
     
  14. Coop47

    Coop47 Poster Extraordinaire

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    Congrats!

    I was just listening to a podcast with amp guru Skip Simmons, and he raves about the Falcon. His general advice is to leave it as is as much as possible. He says he's willing to help people over the phone, so he might be worth a call.
     
  15. Jack Clayton

    Jack Clayton Tele-Holic

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    Can you give me a link to that podcast? Sounds like a great resource.
     
  16. Quacky

    Quacky Tele-Meister

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    I recently saw a video about a rebuild of that amp here's a link you might find it interesting. On a personal note I've been thinking about getting one myself for a while now.
     
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  17. nixdad

    nixdad Tele-Meister

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    Yeah, I think that tone-suck circuit is in a few Gibbys. Yanked it out of Minuteman amps; it helped one, din't help the other.
    Falcons is a different story. Had 3 and loved 'em all. Miss having one.
     
  18. Coop47

    Coop47 Poster Extraordinaire

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    Ugh, I'm not that savvy. But he did a lengthy interview on the Fretboard Journal podcast, and that resulted in a regular podcast called "The Truth About Vintage Amps". I'm sure you can find it by searching "Skip Simmons" in iTunes.
     
  19. Saxonbowman

    Saxonbowman Tele-Meister

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    I have an Epiphone EA-50T which is very similar to the double slant Gibson above, minus the reverb. It too was very trebbly when I got it. It does not have the Sprague network, but has a similar network with discreet components. This is basically the bass control circuit. So far I have bypassed that circuit. It just entailed unsoldering one end of a resistor and moving one wire, easy to reverse If I decide to later. It made a world of difference! It has way more volume, like 10db worth, and sounds much fatter. Bass is still a little weak. I'm going to replace the speaker and see where I want to go from there. There is a high-pass filter network right at the input that seems like it may be sucking some of the bass away. Not going to touch it for now until I get the speaker. I'll try to document all of this when I get the time.
     
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  20. tombob

    tombob Tele-Holic

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    Some Gibson amps have what they called a “Twin T” circuit in the tone stack. Personally I think it killed the sound of what should be a great amp. I was surprised just how much it helped my little ga15rvt. It spent years in my closet until I modded it. The 50’s Gibson amps are amazing, they always sounded very Tweed to me.
     
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