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ttocs

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About ttocs

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  1. I'm trying to load some photos of my amp and not having success. Photobucket doesn't like Win8, it keeps hanging and messing up my computer. I only have 500k on this forum for photo usage, not enough space. I then tried to use the Insert Image button above and I get the "You are not allowed to use that image extension on this board" message. So, no photos. sorry
  2. Wow! Great info! Thanks. Lucky I had a few minutes to read your post Murray. Yeah, I'm on the fence about the "originality" thing. I want it to function as designed firstly, and I want to be able to use it to its fullest. So swapping out parts so as to restore proper function is my main goal. If that means using more modern resistors, I'm ok with that. The capacitor types are a little more of a concern for me, especially those waxy ones. I absolutely want to maintain the speaker! Like I said, everything in the amp looks original from the factory except those caps and one resistor. I'd like to match the replaced caps to original if possible. The tubes are all Sylvania and appear to function normally, except the heater voltage is right at the 10% high mark, measuring about 6.93v. I'd like to clone it twice, once using a field coil speaker, and a second that is setup for a PM speaker. It's a really simple circuit to duplicate but the tubes are the biggest expense, topping out with the metal 6SJ7, which I think is the most important tube in this circuit. Also, it may turn out that the field coil speaker is additionally crucial to the sound of this amp (which I believe is true).
  3. There is a severe lack of information on early Gibson amps, so I thought maybe we can share information on the BR-6(F) models specifically - of course knowing that the sister and cousin models will gladly come into play. I am not an electronics guru, I'm just a tinkerer. I'm using this opportunity to learn more about the world of tubes. My BR-6F is most likely a 1951 production model. The volume pot and speaker were both made in early '51, and the power transformer was made in late 1950. I bought this at a guitar shop and it was very low on volume during the demo but the tone and cleans/distortion was kind of how I remember my '58 Les Paul Amp GA-40 that I had back in the 1970's. I've been looking for this sound for a long time. I got this for a good price and figured that I could work on the volume issue. DISCLAIMER: TINKERING WITH TUBE AMPS CAN BE VERY DANGEROUS! PROPER PRECAUTIONS MUST ALWAYS BE USED. UNPLUG THE POWER CORD. DRAIN THE CAPACITORS. USE THE "ONE HAND" RULE, one hand only is allowed inside the chassis. I opened it up and found that 4 capacitors and possibly 1 resistor had been replaced (it was the only one with a tolerance band on it). The volume problem was solved by re-seating all of the tubes (helped a little) and by re-soldering a broken connection from a pair of the new capacitors (helped a lot). Checking the resistors in-circuit showed that at least a couple of them were high out-of-spec, one of those by a lot. While it's difficult to determine if a resistor is in-spec or low while it's in-circuit, looking for the ones that are high is easy and the one that was way off showed signs of burning once I got a better look at it. It is a 2.2k cathode resistor and measured 2.9k while installed, but it measured 3.8k out-of-circuit! The new resistors I installed are carbon film, all of the original ones are carbon composition. Carbon film is supposed to be lower noise and I gotta' tell 'ya - there's less noise. There's still some hissing but it's pretty slight and only noticeable at no volume a foot away from the speaker. Now if I can just do something about that hummmmmmm. That's all for now. I'll post photos tonight.
  4. Great site! Those amps are in very good condition. Will you be adding information to go with the photos! (I know, lots of work!) I just picked up a BR-6f that I'm pretty sure was made in 1951. It's in rough cosmetic shape but works very well.
  5. I've read your posts with great interest due to my recent purchase of a 1951 or 1952 BR-6f. I haven't found much info on this series/era of amplifiers, so I'm interested in learning all that I can on these amps. My amp is almost totally original. The only items not original include the handle, 4 capacitors, and I "think" 1 resistor (it's the only one with a tolerance band on it). Thank you for posting.
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