[Amps] GS35B questions

[Jim W7RY]

I use SHV connectors.  They can be found on Ebay.

See a picture of them in use on my 8877 amplifier and power supply at:

http://s900.photobucket.com/albums/ac206/w7ry/8877%20Amplifier/

73
Jim W7RY



> -----Original Message-----
> From: rezycle.bin at gmail.com
> Sent: Fri, 10 Sep 2010 00:03:26 +0200
> To: amps at contesting.com
> Subject: [Amps] GS35B questions
> 
> Hi, I am working on a new GS35B HF amp design.
> 
> Some questions:
> 
> -I would like to buy some sockets instead of machining them myself.
> Could you gentlemen direct me to a person selling sockets that
> normally have them in stock or at least can deliver within a month or
> so?
> 
> -What is the proper "burn in" procedure for the GS35B? I was planning
> on running the filament of the tube for some time (how long time?)
> with proper airflow. Do I need to apply HV as well? I don't have a HV
> tester at the moment. I bought the tubes from UR4RLL. They look new /
> unused.
> 
> -I am planning to use the triode control board from WD7S. Any things
> that I should be specially aware of when using that board with the
> GS35B (apart from the mod for higher bias voltage)?
> 
> -I am planning 3650V on the anode. This is significantly higher than
> the "official" data sheets state, however I notice that the official
> data sheets rate the tube for military service with less cooling. Does
> 3650V look like an OK voltage?
> 
> -I am looking for a SAFE way of running the HV cable from an external
> HV PSU cabinet to the RF cabinet.  I know this has been discussed
> numerous times before, but again: what is the best cable I can use and
> what connector should I use? Did we reach a conclusion and some
> reccomendation on that question? I would like to avoid any possibility
> at all for the B+ (hv plus)connector connecting before the B- (hv
> minus) because that may place the RF deck at the HV+ potential if the
> grounding between the two boxes are broken. (I do not plan on hot
> plugging, of course). The minus lead should be isolated from the
> chassis since I plan on using a high wattage drop resistor from
> chassis ground to B- to be able to measure grid current.
> 
> -Should I place the grid drop resistor in the PSU cabinet or in the PA
> deck? I was thinking that placing it in the PA deck would be safer
> because in case only B+ is connected before B-, the grid drop resistor
> would connect B- to chassis ground and not keep the PA deck at B+
> potential (No I am not going to hot plug the B+ connector, but perhaps
> some other operator will attempt just that. You never know what can
> happen in the mid of a contest battle)
> 
> -I have read that running DC instead of AC on the filament is OK.
> However I have read somewhere else that it is not OK. I have an AC
> trafo, but if the primary voltage varies, the filament voltage could
> be too high or too low and this may hurt the tube. Instead I would run
> a regulated DC supply, since the filament current is not that high.
> Any comments on that? Alternatively, any clever way of regulating the
> trafo by a small series drop resistor or something?
> 
> 73
> LB3HC
> Marius
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