Metropoulos Forum

I am well on my way to converting my JMP 50 to "JTM 50" specs. I did not necessarily set out to do that but that's the way it is going and I love the way it is sounding. I currently have 50uf mains, 32uf screens and pi, dual 33 preamp. My question is this:

Is it safe to use a 32/32uf for the mains and pi, while using a 16/16 for the screens?

So the setup would be one half of the 16/16 for the screens and then one half of the 32/32 for the mains and the other for the pi.

I realize I could also replace the screens/pi cap with a 16/16 but I was just trying to figure out a way to lower the screens filtering to 16uf while maintaining the 32uf I have on the pi. Thanks!

jtm50s have 32uf for everything. personally i prefer at least 47uf on the mains

I am with Roe on this, I actually prefer 100 on mains, with 32 screens, PI and x2 in pre-amp, but of course I prefer split cathode in preamp of 50 watters.

JTM50s had a 32+16uF mounted on the inside of the chassis. IIRC 16 for the PI and 32 for the screens.

I assume the earlier amps had 16uf on the PI while the later amps had 32uf

I have photos of a late '67 JMP with tube rectifier and the 16+32 cap. I'm 99% sure it's original.

interesting, I've seen pics with 32uf in all positions (I believe some were on the marstran page)

Oh wow this is interesting. I'm sure you're both right seeing as how much these amps seem to vary.

Is there anywhere to still find a 32\16 cap? I am curious to see what 16 on the screens would sound like on this amp. So to get 32 on the mains was there a dual 16 jumpered?

I am starting to think that I may build a black flag 100 watt. I love EL34's and low filtering! Ghosting and all.

I'm interested in a 32/16 can also, so I can get 32 on the screens and 16 on the PI. Right now I've got 16 on each and I think the screens want a little more tightness.

Edit: Found on here, it's pricey: http://www.vibroworld.com/parts/tech15.html" onclick="window.open(this.href);return false;
One thing you can do is get a 16/16 cap can, and get an axial 16uf cap, put that in parallel with the side you want to make 32.

http://cgi.ebay.co.uk/NOS-ERIE-HUNTS-16 ... 5d2b520474

OOoh that's purty looking! Thanks for all of the into everyone.