Recent content by pavel

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    Jcm800 ef80 build. Part sourcing and chassis question

    I used a Hammond 12 x 7 x 3 chassis for my JCM800 EF80. I built mine with the toroidal PT, so a bit more compact I drilled all my holes with a bunch of step drills and a knockout punch tool and drilled/filed out the hole for the IEC plug. I do have a nice drill press but ended up doing most of...
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    Question about 5F1 baffle grille cloth stapling

    This turned out to be a bit of a headache, actually. A word of advice for others building a 5F1 cabinet -- I finally finished and covered my Champ cab, using the exact dimensions from the Dueltone Amps schematic. I got the very nice Jensen P83 and ran into a snag fitting everything in! It turns...
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    JCM800 Micro EF80 Build

    Cool, thanks for trying that! I have yet to finish my JCM 800/EF80 in the stock config, but this sounds like a cool avenue to experiment with down the line. Or maybe it will just go straight to eleven as-is right off the bat, cold clipper and all :cool: Either way I need to get on with it...
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    JCM800 Micro EF80 Build

    Curious about this -- is this because the half way rectifier only loads up the PT on one half of the waveform?
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    JCM800 Micro EF80 Build

    Meat & Potatoes :-). Presumably you could use a bridge on the tap and a half wave rectifier on the HT winding? The bridge would give less ripple for the higher draw of the EF80 power stage.
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    JCM800 Micro EF80 Build

    The AS-05T240 has a 240V secondary with a 220V tap. Maybe that coupled with two rectifier bridges?
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    Tweed covering with hide glue?

    Perfect, thank you Jason, this is super helpful. I like Behlen's as well, for one it comes in a nice can rather than a plastic bag. But, I believe BT&C is the original supplier that most other suppliers resell anyhow, so no worries. It's reassuring to hear that you can deal with the normal...
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    Tweed covering with hide glue?

    I am getting ready my first tweed covering job on my Champ cabinet and I'd like try to use hide glue like back in the day for some extra mojo (or more likely a big mess :-) ). I use hide glue a bunch for guitar builds but this will be a first for me for this kind of application. Question for...
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    First amp build - Rob Robinette's Micro Champ

    That's pretty impressive for a hand built Chassis.
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    EF80 Micro ???

    Sorry, don't have advice on cab building specific to an EF80 micro -- I am close to start on a micro JCM800 EF80 and was going to stay small, perhaps try an 8" Celestion. I do want to add a AC voltage switch to my build though, because even though I am US based, you know, one of these days I'll...
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    Question about 5F1 baffle grille cloth stapling

    Thanks for the insight guys, very much appreciated! So it sounds like the standoff was standard even on the thicker baffles on the larger cabinets huh? (Because presumably the grille would otherwise rattle regardless of the baffle thickness?).
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    Question about 5F1 baffle grille cloth stapling

    I am curious about the optimal and/or vintage correct way of stapling grille cloth onto a 5F1 Champ baffle. Using the ¼" (or more like 5mm) baltic ply, I see a lot of builders add a ~1" extra strip around the baffle edge to raise the grille above the baffle surface. This seems to also add to...
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    How Would You Fix This?

    You have some off-cuts of the top right? I agree with everyone here that it will be a tall order to make a hard to notice repair, but if it was me, I would take it as a challenge and try on the off cuts to see how close I can get, before going for the toggle switch or any of the other fine...
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    Rob's JCM800 Micro EF80, B+2, B+3, B+4, B+5 voltages?

    I took a stab at calculating the voltages, updated schematic with the hopefully more correct values:
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    Rob's JCM800 Micro EF80, B+2, B+3, B+4, B+5 voltages?

    Ah yes, thank you Dan, I indeed missed a couple of the key dropping resistors having a modified value for the lowered PT voltage. Here is an updated schematic that matches the values in the layout drawing. The heater center tap is different in the torroidal PT setup, I fused the two layout...




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