>At 02:13 AM 12/4/97 EST, KM1H wrote:
>>
>>On Wed, 03 Dec 1997 20:56:03 -0500 "Joe Subich, W8IK" <w8ik@ibm.net>
>>writes:
>>>
>>>The amplifier requires a non-inductive swamping resistor of
>>>aproximately 50 Ohms/25 watts ...snip...
> ... ... *I* learned my lesson about using the
>FT-1K to drive an MLA-2500 the hard (expensive) wasy ... by cooking
>a tube. The problem was most certainly due to overdrive, the "spike"
>on initial key-down, and not parasitics.
>
If you mail me the kaput tube, I will remove the anode, photograph the
insides, and post the pictures so that everyone can see whether the
cathode coating is damaged from overdrive, or the gold is sputtered from
parasitics.
>I still plan to rework my MLA-2500 to better swamp the input, install
>a 2.25:1 input un-un, install a HV "glitch" resistor, replace the
>carbon comp bleeder string, rework the output network ...snip...
Unfortunately, I haven't
>found a suitable replacement for the 8875.
There is nothing else even similar to the 8875, and the MLA-2500 was the
only commercial amplifier that used it. The 8873 was also unique.
Rich...
R. L. Measures, 805-386-3734, AG6K
--
FAQ on WWW: http://www.contesting.com/ampfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|