[SEDXC] Homebrew Amps

[Bill Coleman]

On Sep 22, 2006, at 8:34 AM, JT Croteau wrote:

> Anyone have any schematics/plans/ideas for getting ~200W from either
> 5W or 50W drive without breaking the bank?

There's not a huge difference between 50 watts and 200 watts. That's  
only a single S-unit.

>   I have acquired a nice
> Ten-Tec Argosy that I am cleaning up and it will have a really low
> noise floor and improved dynamic range when I am finished.  Some type
> of foot warmer would also be nice.

If 50 watts is not enough, consider finding a used older-generation  
tube amplifier. Something like an SB-200 can be had for less than $500.

Last year, I bought a used AL-80A from a ham's estate. I spent a bit  
more than $500, but what the heck. It uses a single 3-500Z and with  
50 watts drive will produce about 500 watts or so.

> I know Tokyo Hy-Power has some commercial pre-built options in this
> range but I, and my wallet, would much rather homebrew if possible.

Homebrewing an amplifier can be done, but it isn't cheap. Key  
components, like the HV transformer or tube(s), can easily run you  
over that $500 budget, if you buy them new.

Amplifier design and construction also requires a certain level of  
care and expertise. The voltages can easily kill you. The energy  
stored in the power supplies can be enough to explode components.  
Proper component choice is necessary to avoid catastrophic failures.

You're better off looking for a used amplifier. If you are totally  
focused on homebrew, you should consider buying used amplifiers for  
key parts.

Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901