john <[EMAIL PROTECTED]> made an utterance to the drakelist gang
----------------------------------------------------------------------
I may not be fast, but I'm stubborn. I just finished an amp "conversion"
...which really was more like "use the variable caps, meter , transformer
and case, and trash the rest. The patient in question was a $40 junker
GSB1000 Dentron amp. These were sweep tube jobs that weren't that great to
start with, and this one had been scrapped , taken apart and put in a
box. The good news was, the bits I needed (case, transformer, meter,
variable caps) were all good.
I added a tuned input circuit built on FAR circuits boards, rewound a new
tank coil, since anode Z of the replcement tube (a Russian GI7B ceramic
triode) operates at 2X the voltage of the original sweepers, built a
voltage doubler, built an "air chamber" to provide forced air cooling of
the PA tube, added a power sequencing circuit (again , a FAR circuit board
) using a 555 and a small DIP relay, and built and painted a new panel out
of .050 aluminum sheet.
The GI7B is good for 500W out, and this will do it, with just 40 watts in,
so perhaps my plan for using this on the output of my T4X is not a good
one! The GI7B is a bargin...less than $25 for a 500W out tube.
In any event, I've uploaded pix here:
http://old-radios.com/Temporary/amp2.jpg
http://old-radios.com/Temporary/amp1.jpg
....if anyone's interested. The indicated voltage is V/2 .....
I learned a lot, and didnt kill myself! Two important outcomes!
John K5MO
----------------------------------------------------------------------
Submissions: [EMAIL PROTECTED]
Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body
Hopelessly Lost: [EMAIL PROTECTED] - help in body of message
Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net
----------------------------------------------------------------------
