Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: dude on November 26, 2018, 01:24:39 pm

Title: Size for first two filters
Post by: dude on November 26, 2018, 01:24:39 pm

If I wanted to make a 6V6 Plexi but wanted to be able to use EL34's too, instead of two filter cans at 32/32uf would it be better to use the first can at 50/50uf, other at 32/32uf ? Using GZ34 R tube or 5AR4 or diodes.
 
Also the bias caps, would 10uf @ 100v be good enough for the larger tubes, 6L6s, EL34's?


Thanks,
al

Title: Re: Size for first two filters
Post by: shooter on November 26, 2018, 01:48:57 pm

PS filtering depends 1st on what regulator, some tube type have max cap values, SS loves anything withing reason, I use 50 - 100uf.
next comes the magical PS sag, it's to complex for me so I design to have none, or very little, one less thing to fret about  :icon_biggrin:

Title: Re: Size for first two filters
Post by: mresistor on November 26, 2018, 02:52:11 pm

Doug uses 10uf in both the 6V6 plexi and Plexi 50 bias circuits  so you should be good to go with either one..


a good read on bias supplies is here  http://www.valvewizard.co.uk/bias.html (http://www.valvewizard.co.uk/bias.html)


In Dougs 6V6 plexi he uses a 40uf before the choke. In the 50watt plexi there is 100uf capacitance as the reservoir filter.   Since either one has a solid state rectifier then there are no constraints
placed by a rectifier tube as to input capacitance. I would think that using 50/50uf can up front would be ok for both. 

Title: Re: Size for first two filters
Post by: dude on November 26, 2018, 04:06:21 pm

That's what I was thinking, 50/50 first can, choke between the two 50uf's.


Thanks,
al