Thrashman93
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- Joined
- Jun 25, 2017
- Messages
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Hello all,
Last year I was on the hunt for a JCM800 and I'd like to share what I found and what I discovered later about it.
I found a craigslist post in my neck of the woods of a guy selling a 1982 JCM800 4010 in 2017 and set up a time to visit the guy about the amp at a guitarcenter. We met up and I noticed it was a little beat-up but not horrible; as if it served it's purpose of gigging over the years which is a plus. It worked great at guitarcenter. Sounded good. Had original filter caps, drake OT, Drake choke, Drake Power Tranny. Unmodded. Etc. So I bought it. And played with it several months and over those months I noticed some weird things about it: It had master volume knob static when changing the volume, it hummed the entire time being on and warming up, the preamp volume had the same static and audio cut-out as the MV knob. It had preamp tube hiss, it would squeal at volume 2 and above even without striking the strings, it was very bright, the power tubes would light up like a roman candle and the sound would cut real low.
So after the issues stacked-up, I found a local amp tech and handed it to him. He then found the issues with this amp: 1. The power transformer was wired with wrong guage wire and cut and spliced together with electrical tape and routed OUTSIDE the chassi and back through the back; without using the grommets to run wires through and the only thing preventing it from touching the chassi metal was one strip of electrical tape. 2. There was NO bias set; no bias resistor at all. 3. There was ONE 25 amp house fuse that was bypassed. 4. The tube that would turn into a roman candle stick with electric was actually plugged into a HANGING tube socket internally; it was almost disconnected completely.
Shorten the story a bit--definitely had him fix the internals and he was able to save the original power tranny. New electro harmonix power tubes, only needed a new preamp tube which is now a NOS mesa boogie preamp tube. Has the appropriate .3 amp and 5 amp fuses. Bias resistor back in place. New JJ bran capacitors. Properly biased. Tube socket snugly fit. No more wires and horrible amp-killing wire job.
Conclusion: I have an electronically fixed to spec Marshall 1982 JCM800 4010 with original pcb, original transformers and chokes. I even managed to find a 1960B cab with it last week for only $300 bucks.
*photos aren't uploading for some reason*
Check out my Instagram for what it sounded like before the servicing and with an evm12l: cam_i_am2015
Last year I was on the hunt for a JCM800 and I'd like to share what I found and what I discovered later about it.
I found a craigslist post in my neck of the woods of a guy selling a 1982 JCM800 4010 in 2017 and set up a time to visit the guy about the amp at a guitarcenter. We met up and I noticed it was a little beat-up but not horrible; as if it served it's purpose of gigging over the years which is a plus. It worked great at guitarcenter. Sounded good. Had original filter caps, drake OT, Drake choke, Drake Power Tranny. Unmodded. Etc. So I bought it. And played with it several months and over those months I noticed some weird things about it: It had master volume knob static when changing the volume, it hummed the entire time being on and warming up, the preamp volume had the same static and audio cut-out as the MV knob. It had preamp tube hiss, it would squeal at volume 2 and above even without striking the strings, it was very bright, the power tubes would light up like a roman candle and the sound would cut real low.
So after the issues stacked-up, I found a local amp tech and handed it to him. He then found the issues with this amp: 1. The power transformer was wired with wrong guage wire and cut and spliced together with electrical tape and routed OUTSIDE the chassi and back through the back; without using the grommets to run wires through and the only thing preventing it from touching the chassi metal was one strip of electrical tape. 2. There was NO bias set; no bias resistor at all. 3. There was ONE 25 amp house fuse that was bypassed. 4. The tube that would turn into a roman candle stick with electric was actually plugged into a HANGING tube socket internally; it was almost disconnected completely.
Shorten the story a bit--definitely had him fix the internals and he was able to save the original power tranny. New electro harmonix power tubes, only needed a new preamp tube which is now a NOS mesa boogie preamp tube. Has the appropriate .3 amp and 5 amp fuses. Bias resistor back in place. New JJ bran capacitors. Properly biased. Tube socket snugly fit. No more wires and horrible amp-killing wire job.
Conclusion: I have an electronically fixed to spec Marshall 1982 JCM800 4010 with original pcb, original transformers and chokes. I even managed to find a 1960B cab with it last week for only $300 bucks.
*photos aren't uploading for some reason*
Check out my Instagram for what it sounded like before the servicing and with an evm12l: cam_i_am2015
