Can anybody help identify which mods I have in my 1987X?

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MrRGecko
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Can anybody help identify which mods I have in my 1987X?

Post by MrRGecko » Wed Jan 03, 2018 12:31 pm

So I know I have a switchable bright cap, cascade mod and coupling cap. It also has a PPIMV.
Can anybody help identify which version of the PPIMV and cascade mod I have?

Regarding the PPIMV; I find it HELLA bright and I think that's due to the "A1M" pot? I'm guessing that's an Alpha 1 meg potentiometer? The caps all read "223J 400A". Beyond that, which I'm gonna get switched out I think, what else is going on?

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Also, here's the cascade mod. Can anybody tell me what they see here?
Interestingly with this, when I switch it on, I have to switch to the normal channel inputs as it cascades normal into bright I believe. BUT, when I jump the channels as normal, input 1 still works? Can anybody see why?

Also, why is the PPIMV deemed imperative with the cascade mod? Is it because it's extremely hot and you want to limit what's going to the power amp to keep that cleaner? I always see that you must have one with the cascade mod.

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Thanks!

Littlewyan
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Re: Can anybody help identify which mods I have in my 1987X?

Post by Littlewyan » Fri Jan 05, 2018 9:57 am

Edited

He's used the PPIMV Type 1 shown here https://robrobinette.com/The_Trainwreck_Pages.htm on page 32. I think that's the one that George uses. I've only used Type 2 myself and didn't really like it.

The brightness could be because he's used .022uF Capacitors, which are in series and so are actually .011uF. He should have used .1uF really. Do both sets of capacitors definitely say 223?

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