Goofing-around amplifier project

the thermionic watercooler

Goofing-around amplifier project

Postby Switch » Sat Jul 09, 2016 10:02 pm

So I already have too many projects going on right now...perfect time to add another.

I have a pair of hammond 1615 clones, built out of the remains of a pair I burned up due to stupidity. (Ignoring the DC current limit for a LONG time and by a LOT.)
I have piles of 12L6 and 12W6 tubes (Identical plate curves and typical op points, but the W's are rated for deflection duty)
I've got an aluminum chassis I folded and welded up and then realized was NOT 17" wide to fit the big radio project-it's 9.25"x14"x2.5"
An Antec 200V, 500mA toroid with 12.6V and 6.3V windings

And my first amplifier, from way back in high school, just shorted the power transformer a few weeks back.

Anyway, plan is 6BL8 pentode input/triode cathodyne, driving 12W6's in pentode class AB1. I've forgotten how to determine AB loadlines, so here's my drawings, complete with the erroneously marked Q-point.

Image

If I wind up in class A, I wind up in class A. No big deal. AB will just use the OPT's more effectively.
Switch
 
Posts: 5
Joined: Tue Apr 21, 2009 5:20 pm

Re: Goofing-around amplifier project

Postby Switch » Sun Jul 10, 2016 4:35 pm

Ok, so here's where I'm at now.

Schematic:

Image

Chassis:

Image

Total cost at this point: $0.57 for screws. All the rest was out of the "leftovers" pile.
Switch
 
Posts: 5
Joined: Tue Apr 21, 2009 5:20 pm


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