msg wrote:
cliff wright wrote:
snip

2. I would be quite sure that an 807 based linear would turn into slag
with 2Kv on the plates,...


Please see http://www.cybertheque.org/homebrew/837_linear

This design is not mine but I documented the layout, construction,
and circuitry of a quad 807 (837) linear from silent key
K9KLN. It used a 2KV power supply

Regards,

Michael
Had a look at the old quad GG 807 type linear.
COR! that's a real old bit of ham radio.
My own experience with 1625/807's is that with more than 1KV on the
plate they didn't survive long. Any mismatch or offtuning and flashover
happened pretty fast. Back in the 1960's I had quite a bin full of duds
that went just that way.
Recently I had a fault in my modified kenwood 820s which destroyed 2x
6146B's in a similar way. That's with only 850v plate voltage too.
However it is true that linear amps tend to work better in a high
voltage/low current mode, provided the finals can take it.
My old home brew 100watt linear used a TT21 (KT88 with a top cap plate)
and that worked fine with 1050 volts. Nice and linear and 66% effecient
on 14 Mhz (measured).
I once built an 811A GG linear but never needed the extra power so it
nevergot on the air.
Regards Cliff Wright ZL1BDA