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    What would account for the low-gain input having vastly lower volume than the high-gain input on a JCM 800?

    While far from everybody said the amp sounds like it's behaving as it should, when you and some others did say you think the amp is behaving as it should, I replied with: Your narrative that I was uncivil and unfriendly to people, or to anybody at all, and that I stubbornly rejected their...
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    What would account for the low-gain input having vastly lower volume than the high-gain input on a JCM 800?

    Having thought about this a bit now, the part about installing inline sockets for the three resistors that configure a JCM 800 for either EL34s or 6550s, to make the amp easily switchable between them, I'm thinking this would be brilliant and very usable. Is there any reason to not do this -...
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    What would account for the low-gain input having vastly lower volume than the high-gain input on a JCM 800?

    This is a question that I think is worth answering. Despite its deserved reputation for its high-gain sound, the JCM 800 is an awesome pedal platform and does a gorgeous and very-chimey clean sound, if set right (master cranked, and use the preamp control for volume and thickness adjustment -...
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    Advice for removing PCB-mounted jacks? And is it important to charge new filter cans slowly?

    The soldering iron I bought some years ago from someone locally. It's 60 watts and has a temperature control that lets it be set from 200C up to 450C. I've built a bunch of pedals before, and after burning a solder pad or two, I've generally keep it at 375C and haven't encountered an issue. But...
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    Advice for removing PCB-mounted jacks? And is it important to charge new filter cans slowly?

    I put an extra layer of electric tape around the can in the "second one" photos, and tested the amp out. It seems to work just fine! I dialed in a rough bias, but found that the "matched" KT88 tubes I got for this amp are far from it, sitting right now with mA of 31, 33, 38, 36. Oh well, I'm...
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    Advice for removing PCB-mounted jacks? And is it important to charge new filter cans slowly?

    The bias caps I had been waiting for arrived today. They took a while, and the tracking showed they went back and forth between the same two cities a couple of times, so I guess there was a mail error. But I've installed them now, and reconnected the wires I had removed to be able to flip the...
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    For sale: 7 original vintage Marshall JCM 800 pointer knobs (1978 - 1984?)

    Asking $280 CAD. And the buyer is to pay the shipping. These came off a couple of vintage Marshall JCM 800s. If you sometime encounter a vintage Marshall with a missing original knob, these can be used to help restore them. And these are very rare to come by. Some of the knobs have slight...
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    Questions about forming new filter caps in an amp

    Great info. Thanks!
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    Questions about forming new filter caps in an amp

    With shipping costs, the lightbulb limiters on eBay would cost me at least as much as the variable voltage regulator on Amazon. I guess the voltage regulator is more capable, and I could use it for sound experimentation, too, under-volting (or slightly over-volting?) an amp. When is the time to...
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    Questions about forming new filter caps in an amp

    Can one of those be bought assembled, or is it something to be built at home?
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    Questions about forming new filter caps in an amp

    Do you always do it with high-voltage caps, and is it as simple as just bringing the voltage up slowly the first time the amp is powered on with new filter caps? This is the cheapest variable-voltage regulator I see on Amazon. Would this be fine for the job, or would you recommend something...
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    Advice for removing PCB-mounted jacks? And is it important to charge new filter cans slowly?

    I got the jacks off without damaging the solder pads using desolder braid, a few differently-sized screwdrivers, a couple now-scratched-up fingernails, and patience. And when I installed the new jacks, I did not bend the leads. So, should they need replacing in another few decades, whoever does...
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    Advice for removing PCB-mounted jacks? And is it important to charge new filter cans slowly?

    This is the first time I've done my own amp work. So far, on my 1985 JCM 800, I've replaced the filter cans, the bias trimpot (the original had been replaced with another kind using makeshift top-of-board soldering), converted the amp to 6550 spec, and removed the bias caps. Things have gone...
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    What would account for the low-gain input having vastly lower volume than the high-gain input on a JCM 800?

    I just tried a few different tubes in the preamp sockets, and the sound level was the same, as far as I could tel..
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    What would account for the low-gain input having vastly lower volume than the high-gain input on a JCM 800?

    No. I've ordered new filter cans, bias caps, and some resistors to convert the EL34 amp to 6550. I've also ordered some spare jacks and pots. When all of those things arrive, I'll install the filter cans, bias caps, resistors, and then do the recommended testing with the jacks. If I still am not...
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    What would account for the low-gain input having vastly lower volume than the high-gain input on a JCM 800?

    Definitely not. I own many amps and the JCM 800 sound is exactly what I'm wanting here, and I'm loving it. I'm just questioning the volume I'm getting it at, at a certain setting - after other JCM 800 owners, including my friend who uses their JCM 800 the same way I use mine, told me there...
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    Looking for some grounding connector assemblies for JMP-1 preamp - will happily pay your normal fee + shipping

    A pretty good thought. I'm in Canada. I appreciate the offer and wouldn't mind paying for shipping from the UK, providing it's not crazy. I've bought some pedals from the UK, for which shipping wasn't bad. If an offer from North America doesn't arise, I'll send you a message!
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    Looking for some grounding connector assemblies for JMP-1 preamp - will happily pay your normal fee + shipping

    I'm needing the three grounding connection assemblies for a JMP-1 preamp. If someone here has a JMP-1 for reference or parts, or is familiar with the JMP-1, and can throw the proper parts together, I'll happily pay for the service and the shipping. The wire is of a thick gauge. Two of the...
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    Are solid-shaft, PCB-mount pots for a horizontal-input 2203 still available?

    They work, but their turning resistances are worn mostly away, and their carbon pads will be worn down, lowering the values of the pots and limiting their functionality. I previously replaced the pots in a 1982 JCM 800, and the value difference between the old and new pots was huge, and putting...
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    Are solid-shaft, PCB-mount pots for a horizontal-input 2203 still available?

    Apparently, the earlier horizontal-input 2203s used solid-shaft, PCB-mounted pots, which use set-screw knobs, before Marshall switched to split-shaft / knurled PCB-mounted pots, which use push-on knobs. My 1985 2203 has solid-shaft pots and set-screw knobs. It seems replacement pot kits are...

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