[Amps] 8877 in Alpha 9500

[Jim Garland]

	The Alpha 9500 uses a single 8877 with about 3600V (no load) on the
plate, dropping to about 3200V under load. The low plate voltage allows
Alpha to use air variable tuning caps with moderate plate spacing (.08" or
so), which lend themselves to stepper motor control. I believe the same
plate transformer is used in the Alpha 8410 (uses a pair of rebranded
4CX1000a), and weighs about 35 lbs.The amp will produce a maximum of 2000W
output (plus or minus), though pushing it above 1500W is not recommended. 
	 One can specify either a Chinese 8877 ($900) or an Eimac ($1500).
According to Alpha, they've had very good luck with the Chinese tubes and
see no user benefit in using the Eimac tubes. BTW, the Alpha 9500 uses a
pair Chinese-made Gigavac clone vacuum relays. I believe the Gigavac p/n is
model 41A, and they're a bit heavier duty than the common RJ1a, but also
somewhat noiser. Noisy relay clicking on QSK is a problem with the 9500
because of the way the relay board is mounted on the back panel of the
amplifier, which acts like a sounding board.
73,
Jim W8ZR