UPDATE-1983 JCM 800 2203 gut shot- normal or modded?

Here’s a quick pic of caps top side

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RedPlated said:
Yep your right. These are one positive and one negative rather than the typical dual can. Maybe these are 100uF single cans vs a paralleled 50uF dual can. They really should be dual cans as the voltage stability increases when done that way.

What's the value of the cans? And voltage ratings?
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My 74 came stock with Daly single can caps which was the reason one started to leak due to overheating/over voltage. I did replace it with properly rated modern single cans though.
 
Get those caps out and replace with ARS 50/50uF @ 500v.

Those caps are underrated in voltage. They are 175uF as they are in series. That's super stiff on the screens especially.

Good call on Chubbs. I think he found your issue.
 
glpg80 said:
I really hate JJ and F&T caps, personally. It’s good that it’s been recapped though.

Jeremy and I both swear by ARS both tonally and in reliability.

You should be proud of that amp. I prefer early 80’s JCM800s. Good score 👍
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I can definitely hear the goodness in it but can tell that my low end feels off
it’s not a fair comparison but my Hopkins just nails it in every way
the 83 seems like it will be pretty aggressive when right
 
RedPlated said:
Get those caps out and replace with ARS 50/50uF @ 500v.

Those caps are underrated in voltage. They are 175uF as they are in series. That's super stiff on the screens especially.
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That makes sense. I’ll order some and see when I can have them changed out. My tech isn’t asking on any new work right now due to overload. Ugh
 
RedPlated said:
Get those caps out and replace with ARS 50/50uF @ 500v.

Those caps are underrated in voltage. They are 175uF as they are in series. That's super stiff on the screens especially.

Good call on Chubbs. I think he found your issue.
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Well in series the cap value half’s and the voltage rating doubles, so they’re 175uF total at 775V total. That’s more than what I run in my Enmity mod by far capacitance wise for screens or B+

OP that amp likely just needs properly recapped.
 
glpg80 said:
Well in series the cap value half’s and the voltage rating doubles, so they’re 175uF total at 775V total. That’s more than what I run in my Enmity mod by far capacitance wise for screens or B+

OP that amp likely just needs properly recapped.
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Yep 350/2 in series for 175uF.

The reason there are dual cans in these amps is because of the voltage. One 50/50uF can paralleled equals 100uF total and then in series, back at 50uF at 1000v.
 
Ordered!
thanks to everyone who helped get this figured out today. That’s why I love this forum. You guys know your shit! Greatly appreciated
I’ll do a follow up after the cap job. Should be a bout a week or so
 
FourT6and2 said:
I believe that MIGHT be from ARS themselves. When I bought ARS caps a few years ago, I bought them on eBay direct from ARS. For some reason they don't sell them direct from their website. Only on eBay. I dunno... they haven't figured out web stores yet lol.
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RedPlated said:
For future reference, you can call ARS direct and order over the phone. That's how I do it.
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Over the phone is how I do it too. I prefer to use a size you can’t get online and have to order direct.
 
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