Greetings from Japan!!
I have an MLA-2500B working well, however worry about
degradation of the tubes of 8875, wonder triode.
It's difficult to find spare tubes now.
I am considering conversion to use Svetlana 3CX300A1
against 8875's will pass away.
3CX300A1 is designed for audio amplifier for AB1 class
with small grid dissipation of 1W.
In my conversion idea, a pair of 3CX300A1 is used as class
AB1 GG amp. If 170V winding of MLA-2500B transformer
is used for grid bias circuit with negative rectifying. The ALC
signal can be obtained easily from plus grid swing region
as we used to implement for 6146 AB1 GC amp.
I think the cathode driven impedance of two 3CX300A1's is
little bit less than 50 ohm, may need troid magnetics.
Any comments ?
'73 de JA2DHC/1 Kazuo Ohashi
QTH: Fujisawa, Kanagawa, Japan
PBBS: JA2DHC@JL1ZND.11.JNET1.JPN.AS
WebPage: http://www.ny.airnet.ne.jp/ohashi/
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