Metropoulos Forum

Has this been covered? I'm learning that the cap (aka as the Death Cap) plays a significant role in the tone of the amp. Does anyone know anything about this or have photo's.

BTW, Ed's amp had a polarity switch.

Do you have any pics? I did 2 of them a few months ago.

The pros think we are nuts putting these things in our builds and they are right! I've been shocked pretty good back in the day when gigging with my old 50w. Touch your lip to the microphone while playing and zap! Still, I put a dummy polarity in all my builds now. Here is a pic of the 50w, that is a .05uf 1000v cap. If it fails, your chassis goes live 120v. Ralle started all this nonsense and I was right on his heals. Forgot how I wire these at the moment, will look.

Cool, so you're electrically doing the polarity thing, but just not on a little tag board. Would love to see how it's wired when you get a chance. Thanks bro.

In that pic, that's just how it was wired stock in a 73 50w Marshall. The plexies had them wired on the tag board for the most part. I can post pics of how I have it set up in a new build grounded with a three prong plug and how they were actually wired in the old 68 plexies for a two prong plug.

Hmm. So even with a 3 prong grounded power cord, is the chassis going live if the cap fails? Or will that only be the case with the 2 prong?

Yeah man, pics of both would be great. Definitely going to use a little tag board and do the polarity switch/cap/thingamajiggy.

Does anyone have a schematic for this?
I don't think i have ever heard of this before and would like to understand what its for and what it does , maybe try it out myself.
Thnx.

If you do this then take some steps to prevent your guitar from shocking you. Some install a cap in the guitar. but I guess even a buffer pedal might help

I"m having a thought about this subject. The chassis I bought to build this amp doesn't have that 3rd hole for the polarity switch. But instead of drilling one, I have a switch that I used to use for dual B+ PT. Since the new PT is going to be a straight forward, non B+ optional type, I was thinking that I could still realize the polarity functions with that 3PDT switch. Thoughts?

jnew wrote:I"m having a thought about this subject. The chassis I bought to build this amp doesn't have that 3rd hole for the polarity switch. But instead of drilling one, I have a switch that I used to use for dual B+ PT. Since the new PT is going to be a straight forward, non B+ optional type, I was thinking that I could still realize the polarity functions with that 3PDT switch. Thoughts?

I think they have to be separate switches but maybe not....

Aren't they though? By that I mean, when switching from lower B+ to higher B+, they are two completely different circuits and safely segregated from one another. No?