Metropoulos Forum

Hi all I am currently in the process of acquiring parts for a new build and have %90 in order to do a 1986. I would like to use a gz34 rectifier instead of diodes but I’m unsure about filtering. Would it be okay to use half of a 50/50 cap for mains 32/32 for Pi and screens and dual 33 on the board. Will be using marstran 784-139 ot and 1202-118 pt using metro 50 w layout just substitute The tube rectifier In place of the bridge rectifier

Yes, You should be ok with that...
I have a Hybrid JTM50/JCM800 combo (Bluesbreaker) amp that is Tube Rectified (GZ34) with a full 50/50 mains - no Problems.. I would not go any higher than the 50/50... Anything under that is fine.. A good GZ34 can handle about 60uf..

figgystardust wrote: ↑

Sat Jan 23, 2021 12:31 am

Hi all I am currently in the process of acquiring parts for a new build and have %90 in order to do a 1986. I would like to use a gz34 rectifier instead of diodes but I’m unsure about filtering. Would it be okay to use half of a 50/50 cap for mains 32/32 for Pi and screens and dual 33 on the board. Will be using marstran 784-139 ot and 1202-118 pt using metro 50 w layout just substitute The tube rectifier In place of the bridge rectifier

Sounds perfect.
Should not go higher than 64uF for first filter on a GZ34 as it will stress it unduly.
I tend to use 48uF (so 50uF you propose is fine).
The other values will be nice and tight but not stiff.
From a recent dalliance of mine might I suggest you consider using KT88s and lowering your output grid leaks to 100k. I built one of these recently and it was snapped up by a session/backing artist as it had all the balls of a JTM45/100 without being too loud.