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Meanwhile in Las Vegas...

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  • Meanwhile in Las Vegas...

    I haven't taken on many projects lately. I was pretty depressed after my storage unit was burglarized a little over a year ago. I lost all of my vintage amps, conversions, and kits. It was hard to work on anything without dwelling upon my treasured equipment that was gone forever. It's difficult to type this 15 months later, but I'm getting tired of my Vibro Champ SX that was the only working amplifier that I had left. Maybe that was the inspiration I needed.

    At the time I was robbed, I had on my bench a Silvertone 1482 that I was in the process of rebuilding, and in queue a Bogen CHB10A PA amp that I planned to convert. I've knocked the year plus layer of dust from them, and dug back in.

    I've got the 1482 running after replacing the filter capacitors in the power supply, and changing out cathode capacitors. It was kind of a mess. At some time someone had moved the inputs to the front of the amp. I guess they didn't like plugging into the back. I didn't like the look of it, so I moved everything back to the original locations. It's as quiet as a church mouse, and sounds pretty good, but I'll wait to do any other modifications until I get the speaker cabinet completed. I've got a vintage P12R that I plan to use, and want to optimize for it.

    I've just started on the Bogen, and haven't done much yet besides gutting the things that won't be needed. I tested the amp initially. It was working, but noisy, and after a few minutes it burned out R14 in the power supply. Today I plan to replace the filter caps, the bad resistor and change the input to something like a champ amp. It's cold here today, and the propane heater has been warming up the shop for the last hour. I'm going in...

    I'm not over it, but it's fun to get back into the amps.Click image for larger version

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  • #2
    I have the Bogen amp back together. I mounted the new filter caps on a pair of terminal strips. The input is now 67K on the grid with a 1 meg to ground.

    It doesn't sound bad. When it's dimed, it's a little farty, but rolled off a little the bass response is ok. It's a bit noisy, but for the first fire-up I'm happy. I'll check some voltages tomorrow.
    Click image for larger version

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    • #3
      Great that you're back on the horse Looking forward to seeing how it progresses.

      Sucks about the thievery. Especially so when it's stuff you've made or restored because you can't even quantify the personal value. It's happened to me too and there's definitely an added feeling of violation when you've loved and nurtured the things that were taken. I swore if I ever caught the bastards that I would peel them. A very unattractive thought to have, but I was seriously pissed.
      "Take two placebos, works twice as well." Enzo

      "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

      "Being born on third base and thinking that you must have hit a triple is pure delusion!" Steve A

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      • #4
        Thanks Chuck, The whole experience was one that I'd like to forget. I wen't through something similar about thirty years ago when my house was burglarized. This time was worse though. I lost less, but it felt like much more because of the personal nature of the items taken. Anyhow, I'm not defeated, and I can cobble some new stuff together.

        The shop's warming up. Today I'll probably be working on a couple of guitars. One is a parlor sized electric that was somewhat inspired by a thread a while back about B&G guitars, the other a Duo-Sonic replica.

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        • #5
          I made some progress on the Duo-S. Sunday wasn't the most productive, but I did get the fingerboard glued on. Yesterday afternoon we had nice weather, so I took the opportunity to cut up the material for the cabinets that I'll be needing, and for another that I'm doing for a friend. They're nothing special, just some birch plywood, nails, and glue. I assembled the head cabinet, and speaker enclosure for the 1482. It's going to get a brown/oxblood combination. For the Bogen, I think I'll use some python snakeskin tolex that I've got on hand.
          Click image for larger version

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          • #6
            Nice work, John!
            "Yeah, well, you know, that's just, like, your opinion, man."

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            • #7
              There's not much to report. I'm pretty busy working at the stuff that pays bills this week. I'm making some design drawings for the pickup on the parlor. I'm going to try something on a six string, six coil format. I've got some 2mm X 4mm neodymium disc magnets that I picked up just for this purpose a few months ago. It'll be mounted in the sound hole.

              Originally posted by The Dude View Post
              Nice work, John!
              Thanks Dude!

              No new pictures, but here's a guitar that I finished last month. It's my take on the Fender '51 with an ash body, and a one piece pao ferro neck.
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              • #8
                I don't have the tools, time, or inclination for the woodworking side of things. (Probably not the talent either). I do have great admiration for those of you who do. Thanks for the pics, John. I never get tired of seeing the awesome creations some of you are building.
                "Yeah, well, you know, that's just, like, your opinion, man."

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                • #9
                  What he said^^^^^^^^^^^^^^^^^^

                  I always find your builds very 'eloquent'. Designed to be eminently useful and not so much simple as well considered. If I'm ever flush you're going to hear from me.
                  "Take two placebos, works twice as well." Enzo

                  "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

                  "Being born on third base and thinking that you must have hit a triple is pure delusion!" Steve A

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                  • #10
                    You can get flush in Vegas!
                    "Everything is better with a tube. I have a customer with an all-tube pacemaker. His heartbeat is steady, reassuring and dependable, not like a modern heartbeat. And if it goes wrong he can fix it himself. You can't do that with SMD." - Mick Bailey

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                    • #11
                      Thanks guys, I'm looking forward to a day off on Monday to get back to things. I've been working 10-12 hour days setting up exhibits at the convention center all week. I may need the day to just heal.

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                      • #12
                        Yesterday was a short day. It was cool to be home early enough to make some progress. The speaker cabinet is moving along. I need to get some hardware ordered. It's nearly ready for covering.
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                        • #13
                          The weather over the weekend was much warmer than it had been here for weeks. For covering cabinets, I use a water based contact adhesive. It works great when it's warm, but it doesn't do as well in cold, or humid situations. Sunday was the day I'd been waiting for. I covered the shells, and screwed the shiny pieces on. I really like the color combo. The grill fabric was marked down in price because of irregularities. It's crap, and I'll be replacing it soon. Next up is beautifying the face of this mutt. Last night, I Listened to the old P12R in the new speaker cabinet for the first time. It all sounded very solid, and louder than I expected.

                          Here are a couple of necks that I'm working on as well. One will be for the Duo-Sonic, and the other is for a friend.

                          I went back to work full time mid January. I'm loving it, but I sure don't have much spare time anymore.

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                          • #14
                            Originally posted by John_H View Post
                            I have the Bogen amp back together. I mounted the new filter caps on a pair of terminal strips. The input is now 67K on the grid with a 1 meg to ground.

                            It doesn't sound bad. When it's dimed, it's a little farty, but rolled off a little the bass response is ok. It's a bit noisy, but for the first fire-up I'm happy. I'll check some voltages tomorrow.
                            Which cap did you change to roll off the low end? What did you change it to? Perhaps you should go even smaller. You should also play with the amount of negative feedback to see what you like best. Maybe change R11 to 51k in series with a 500k pot just for experimentation. (Is R9 really connected like that? (I'm no circuit guru, so it it is correct, I'm at a loss.)

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                            • #15
                              Which cap did you change to roll off the low end?
                              I was referring to rolling off the volume. The amp is a little better now that it's run for a few hours. I set it aside for a while to concentrate on other stuff. I'll get back to it soon.

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