[600MRG] 630 meter Homebrew

[Kenneth G. Gordon]

On 28 Jan 2018 at 21:37, Dwight Blevins via 600MRG wrote:

> I used a 1625 for the final, much the same tube as the 6BG6, 807, 1625, 6l6, 
> etc. It produces about 20 watts output.

Hello, Ike.

First of all, a 1625 IS an 807....with a 12V filament. 6BG6 IS an 807 in a more compact 
octal-based package used for early TV horzontal output tubes. 

6L6 is about 1/2 of an 807...unless you get the metal ones, and run them upside down in a 
tub of oil or even water, if you dare. Then abuse the heck out of them. I knew a ham in 
Montana who got 300 watts out of a pair of 6L6s that way....for a while.... :-)

We used to buy 1625s for $0.10 each. The military had millions of them made for WWII and 
after. I think at least 1/2 of those millions are still around. :-)

Class C typical ICAS ratings for 807/1625 are 75 watts input, and ~50 watts output at up to 
60 MHz. at a plate voltage of 750 VDC, and screen voltage of 300 VDC. Grid bias -45 VDC. 
Driving power required 0.3 watts.

A pair of them in push-pull Class B or AB2 will output ~120 watts.

They are a good tube and very rugged.

There were uprated versions of the 807/1625 made too, the 5933, I believe.

At 20 watts output, your voltages must be a little low.

Good job, Ike.

Carry on.

Ken W7EKB

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