There's very little (if any) room inside these Dentron amps, so I think the best solution for tube selection is a single tube. Like a 3CX800/4CX800
Jan N8CBX

Okay, thanks for the comments.
I did a little calculation on plate dissipation:
1900V * 0.400A = 760W
760W - 400W = 360W (plate dissipation)
400W/760W = 52% eff.
Advertised value for p/d is 350W, so it looks like I'm right on track with the specs. And with a better anode supply, I could get better efficiency too.
Jan N8CBX
73

I have a one GI-7b, tube amp that I built and I was wondering what others are reaching in output power. On 40M and with about 30W drive, I get an honest 400W with 400mA Anode/100mA grid currents. I get about the same numbers on 80M too. I pushed Ia & Ig as far as I dare, as those are about the max according to the tube's spec sheets.
Anode voltage at the tube is 2162V unloaded; 1900V loaded. I know I'm a little short on HV filter capacitance, but there wasn't much room available.
Jan N8CBX

You say this has been asked (and discussed, I guess) before, and I would like to review those discussions if I can find them, but I don't think the FCC as any rulings against electronic "kits" manufacturers, do they?
Jan N8CBX

This is nothing new, I have heard 160M key clicks on 80M as well as listening to others saying that they hear them too (at a faint signal level). I actually heard some during the recent 160M contest a week or two ago.
I would think a Pi-L net, tank circuit in a legal limit, 160M amp would clean up any harmonics for good.
Jan N8CBX

Could one use electrical power lines as an antenna (doing it somehow in a very safe manner?). I remember my first cordless telephone (1.8 Mhz I think) used the house electrical wiring as the antenna.
Jan N8CBX

I'm sorry. The 2100v is the anode DC voltage out of the voltage doubler circuit that I am using now. The plate windings make about 800VAC @ 1.5A-1.6A, so the total AC voltage would be about 800 + 240 = 1040VAC, then connected to the doubler/rectify/filter circuit to hopefully bring it up to about 2700VDC, or close to that.
So you are saying there could be insulation breakdown in the secondary? I see that now.
Jan

I want to experiment with adding a 240 pri/240 sec transformer in series with the plate transformer of a 500w amplifer (using 572b tubes). The current anode voltage is about 2100v, and I would expect to see about a 400v-600v increase (getting close to 3kv). Anything I need to watch out for connecting the two transformers in series?
I can easily select the secondary transformer's rating to closely match the primary one (about 1.2A)
Jan

Ameritron sells the whole suppressor assembly for about $37, so I'm going to do just that.
Thanks Bryan, but why doesn't one buy the "Little Devil" Ohmite type which is an original carbon resistor?
Jan

Here's a picture of it from W8JI's website
http://www.w8ji.com/images/Amplifier/AL811H/AL811H-parasitic-top.jpg
Jan

I would like to know the component values of the AL-572 parasitic suppressor. I would to scratch build a pair for my pair of 572s
Thanks,
Jan N8CBX

The 3M foil tape looks interesting. I know MCM sells it.
The foil thickness that I quoted (0.0035") is true. The measurement was done with my 1" micrometer. Ebay has a tremendous amount of copper cladded boards.
Jan

I don't want to use any chemicals or milling. 20 years ago at the Hamvention, I purchased some one-sided circuit board material, that had about 0.0035" copper clad foil. I was able to score it with a #11 x-acto blade knife and then actually peel the foil off the board with pliers. Its all gone now, and I'm looking for of this type of board material to buy. Anyone know of a vendor that sells it?
(Again, I want to score & peel it manually, using NO chemicals and any milling)
Thanks
Jan N8CBX

Frank,
I found a 12.6VCT transformer from RF Parts that I'm going to buy. They have a wide selection, by the way.
http://rfparts.com/transformer.html#low
Jan

Bob,
Why? I aready restored a SB-200 (check out my QRZ.com page) and like it. I bought a CBer's version of a SB-200 recently (it was junk & burnt up, and paid too much) and I want to use & do something different than with the 572Bs.
Jan N8CBX