Any of the 4X150/250 family can be run cathode driven, but not grounded
grid. The control grid is biased and grounded for RF. The benefit is less
power wasted in a swamped grid resistor and the driving power adds to the
output
See the Tokyo High Power HL-1K/A for an example, a nice compact well behaved
amp that sometimes shows up real cheap.
http://bama.edebris.com/manuals/tokyohpl/hl1ka
Carl
KM1H
----- Original Message -----
From: "Roger (K8RI)" <k8ri@rogerhalstead.com>
To: <amps@contesting.com>
Sent: Monday, March 25, 2013 4:14 PM
Subject: Re: [Amps] 8650AS Grounded Grid
On 3/25/2013 11:21 AM, Glen Zook wrote:
The 8560A is basically a 4CX250B with conduction cooling rather than air
cooling. Therefore, I would look at the various circuits for the
4CX250B.
If you have the BeO2 block, it's easy to machine a solid anode block to
match for the GI-7B
73
Roger (K8RI)
The Russian GI-7b and GI-7bT tubes work well in the SB-230. However,
they do require a fan or blower.
Glen, K9STH
Website: http://k9sth.com
________________________________
From: K4MT <k4mt@yahoo.com>
To: "Amps@contesting.com" <Amps@contesting.com>
Sent: Monday, March 25, 2013 2:03 AM
Subject: [Amps] 8650AS Grounded Grid
I know some tetrodes have been successfully run in cathode fed grounded
grid configuration. Is the 8560AS one that will run grounded grid without
going through the trouble of creating screen supply? I have been
thinking about putting one in my SB-230 to keep the silent operation.
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