[ARC5] 1625 question

[Robert Downs]

That was to use the tube in grounded grid configuration as an AB-1 or AB-2 linear.  In the 1625, the suppressor grid was internally connected to the cathode (unlike the 837 which wasn’t/isn’t cheap).  Only certain brands could be so modified because some had the connection made external to the tube but internal to the socket.  And some made the connection inside the envelope.

 

Robert Downs - Houston

WA5CAB

 

From: arc5-bounces at mailman.qth.net [mailto:arc5-bounces at mailman.qth.net] On Behalf Of jeepp
Sent: Tuesday, February 06, 2018 06:04 AM
To: 'Ron.K3PID'; ARC5 at mailman.qth.net
Subject: Re: [ARC5] 1625 question

 

The old PH linear, etc. amp used 4 1625s at about a kv.  I recall that one had to use certain physical variants of the tube such that one could drill onto the side of the tube base and tie pins together to change the tube to either a triode or tetrode?  807s could not be so modified, however.  But, 1625s are cheap....still.

Jeep K3HVG

 

 

 

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