Thanks, Joe - your suggestion about EL-509 lead me to another prospect - the
GI7B triode. Looking at some data sheets, it appears to be characterized
between 700 and 1.5kv on plate, and has 300W plate dissipation. There are a
number of articles posted about using this in HF applications, including
somewhere the GLA-1000 itself. By the way, I was thinking of this as a monoband
amp (doing away with the existing HF tank circuitry.)
More reading to go.....
Tks,
Dave
> From: w4tv@subich.com
> To: wb0gaz@hotmail.com; amps@contesting.com
> Subject: RE: [Amps] Tube suggestion needed - 6 and/or 2M ~500W level
> with800-1kv on plate?
> Date: Sat, 21 Jun 2008 18:04:45 -0400
>
>
> If you really want to use the GLA-1000 on six meters consider
> converting it as a monoband amplifier with EL-509s. Yes, the
> 509 is a sweep tube but Far Circuits has a replacement circuit
> board, you should be able to add a tuned input and optimize
> a monoband output circuit. You will need to take some care to
> tame the tubes but as you point out sweep tubes can be made to
> work and since you have the GLA-1000 about the only thing you
> have to lose is your time if you can't make the conversion
> work.
>
> 73,
>
> ... Joe, W4TV
>
>
>
>
>> -----Original Message-----
>> From: amps-bounces@contesting.com
>> [mailto:amps-bounces@contesting.com] On Behalf Of david feldman
>> Sent: Saturday, June 21, 2008 3:15 PM
>> To: Harold Mandel; Carl; amps@contesting.com
>> Subject: Re: [Amps] Tube suggestion needed - 6 and/or 2M
>> ~500W level with800-1kv on plate?
>>
>>
>>
>> To take it back to the original interest - can the GLA1000 in
>> this case be used as a mule to build a portable tube-based 6M
>> amp (2M was something of an afterthought when I made the
>> posting) of middling power level consistent with it's power
>> supply. For this purpose, tubes are preferred over solid
>> state, small is important, and self-contained is important.
>> The GLA1000 is on hand, and from a project perspective, it
>> seems interesting to me. What I've gathered so far is that
>> there are probably no clearly-suitable tubes as a starting
>> point (the 1KV plate voltage being the main barrier), and
>> most likely the project will go no further (SB-200's
>> converted to 6M are common enough and although a little
>> larger, wouldn't have the new-design engineering challenges.)
>>
>> Thanks to everyone for the various insightful suggestions and
>> discussion!
>>
>> Dave
>>
>>> Subject: RE: [Amps] Tube suggestion needed - 6 and/or 2M
>> ~500W level
>>> with800-1kv on plate?
>>> Date: Sat, 21 Jun 2008 14:20:20 -0400
>>> From: hmandel@barantelecom.com
>>> To: km1h@jeremy.mv.com; wb0gaz@hotmail.com; amps@contesting.com
>>>
>>> {snip}
>>> One idea Ive not tried is to take a regular 4CX250B and remove the
>>> radiator (they are soldered on) and then make up your own
>> solid block.
>>> Or saw off one side of fins and replace with a brass plate.
>> Then mount
>>> a muffin fan on top of the cabinet to draw out some heat thru the
>>> remaining fins while another fan blows on the heat sink. {snip}
>>>
>>> Doesn't all this sound cost-inefficient, somewhat?
>>>
>>> Are you in desperate straits to get this particular
>>> machine configured with so irregular a design?
>>>
>>> My next question is directed towards the
>>> RF Circulating Current model, as yet-unbuilt,
>>> that extensive modifications in an untried
>>> cavity will produce......
>>>
>>> However, science for the benefit of learning
>>> is fruitful at any expense.
>>>
>>> "The operation was a success, but the patient died."
>>>
>>> Good hunting, "hals und beinbruch!"
>>>
>>> Harold Mandel
>>> W4HBM
>>
>> _________________________________________________________________
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>> Messenger.
>> http://www.windowslive.com/messenger/connect_your_way.html?oci
> d=TXT_TAGLM_WL_Refresh_messenger_062008
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