SHV connectors look like a good candidate. This reference
http://en.wikipedia.org/wiki/SHV_connector describes what I am looking
for: center pin is engaged after the casing is engaged. Center pin is
disengaged before the casing on removal. This prevents the whole rf
deck to reach Bpluss potential.
However on your linear, it looks like the ground (casing on the SHV
connector) is not isolated from chassis ground. On a grounded grid
amp, if one want to measure grud current, I guess one needs an
isolated Bminus lead? Alternatively, running Bminus in a separate lead
can be done as described (however I dont think I want to do that on my
amp). How have you solved grid current metering in your case? I know
metering the grid to chassis circuit can work, but that will not give
a low reactance RF circuit from grid to chassis and may cause
instability.
73
Marius
LB3HC
On Fri, Sep 10, 2010 at 3:11 AM, Jim W7RY <w7ry@inbox.com> wrote:
> 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@gmail.com
>> Sent: Fri, 10 Sep 2010 00:03:26 +0200
>> To: amps@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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>> [http://lists.contesting.com/mailman/listinfo/amps]
>
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