#168075  by OsamaKeefe
 
Hey all, I've got a question about a mod that maybe someone can help me with.

Just scored a '76 Silverface Twin with two E-120s. The guy I got it from got it from another guy in New York I'm pretty sure. The first guy had done some kind of mod, obviously with Jerry in mind. The right-most side of the back "control panel" has a single input with a knob next to it labeled "pwramp in". Basically a power amp input jack. Any idea what it's for or how I'd utilize it? Don't know much about electronics but I'd love to hear some ideas on how I could use it in the future?
(I don't know how to post pictures yet otherwise there would be one)
 #168076  by Pointclear
 
It’s “probably” a preamp tap. Jerry famously used a line out to a McIntosh mc2300 as a power amp.
If you’re not confident about the mods or the previous owner can’t clarify what’s going on specifically, I’d post some gut shots on here and/or take the amp to a reliable tech that can service the amp and fill you in the mods.
 #168086  by strumminsix
 
Poweramp In is the opposite of preamp out.

The latter is Jerry. The former would be to use the combo as a power and speaker box like if using a modeling unit that needs amplification.
 #168090  by Gr8fulCadi
 
strumminsix wrote: Sat Sep 05, 2020 3:55 pm Poweramp In is the opposite of preamp out.

The latter is Jerry. The former would be to use the combo as a power and speaker box like if using a modeling unit that needs amplification.
That’s what I first thought of too. Then thinking about it, maybe it’s labeled in a way that, “this here jack ‘goes’ to a poweramp in? But that would be a very confusing way of labeling it, who knows, I highly doubt it. I would post picks to verify tho.
 #168091  by Jon S.
 
OsamaKeefe wrote: Thu Sep 03, 2020 8:18 pmThe right-most side of the back "control panel" has a single input with a knob next to it labeled "pwramp in". Basically a power amp input jack.
I'd be surprised if this were not actually a preamp out, i.e., "run from this jack into the poweramp."

If it were literally a "run the power amp into here" jack, one of two things would happen: the power amp would go directly to the speaker(s), i.e., the jack is really a speaker(s) jack; you'd blow the crap out of the amp you're running into!
 #168120  by OsamaKeefe
 
I've looked high and low and haven't found much on the subject. What I do find, I don't really understand :lol: I'm not in dire need of a solution, but I think it's an interesting thing that someone on here could make sense of. Plus, it sounds great as a combo, but if I could get a more Jerry-esque rig out of this (you know the type - Preamp, an expensive Mcintosh eBay find, and an even more expensive speaker cab) it sure would be neat. My logic is, I know all the parts necessary for a good Jerry rig. If I can kill two birds with one stone here utilizing this mod then I'll happily take it.