You must be joking Rich? I have in front of me en old manual on transmitting
tubes: The RCA AIR COOLED TRANSMITTING TUBES from 1938 and plenty of
grounded cathode neutralized finals there. We used neutralized high mu
triodes til up in the fifties, remember. Nothing unusual then, Rich?
I will try to test a grounded cathode, grid driven and a( high mu triode
connected ) 8072s or 8122s with 50 or 22.5 ohms dummy across the input.
Eventually with undecoupled cathode resistors to improve linearity and
stability. At least at 80 meters it may be stable. On other bands it may
eventually oscillate.
The above manual is for sale. Any bids?
Hej daa! de Hans SM5KI
----------
>Från: measures <measures@vcnet.com>
>Till: "AMPS" <amps@contesting.com>
>Ämne: Re: [AMPS] figuring tank Zbased on loaded Ep?
>Datum: fre 22 okt 1999 01.12
>
>
>>
>>As my kids used to say when little, "But WHYYYYY?"
>>
>Because roughly 250v-min. on the anode is what you have to work with.
>If you attempt to go lower that c. 250v, you make IMD go up. If you go
>for more than 250v, P goes down.
>
>>I'm thinking you are talking GG.
>
>yes
>
>>More P than plate V*I => Lower Z than plate V/I.
>>Source I is more than plate I.
>>Am I right?
>
>? I have no idea what "Source I" is.
>
>
>>What about a grounded cathode triode amp?
>>
>? Up to about 200kHz, it is possible to construct a grid-driven
>neutralized, triode amplifier, providing you use a triode with a Mu of 5
>- maximum. .
>
>later, Bob
>>
>>----------
>>| From: measures <measures@vcnet.com>
>>| To: AMPS <amps@contesting.com>
>>| Subject: Re: [AMPS] figuring tank Zbased on loaded Ep?
To: <amps@contesting.com>
>>| Date: Thursday, October 21, 1999 6:24 PM
>>|
>>|
>>| >measures wrote:
>>| >
>>| >>Ä u gotta look at the peak AC anode volts, loaded. For a triode, this
>>
>>| >>usually about 250v less than the supply.
>>| >
>>| >Why? Why 250V? .......
>>|
>>| Good question, Jon
>>|
>>| For 8877s, 3cx800A7s, 3-400Zs, 3-500Zs and similar high Mu triodes,
>>| roughly 250v minimum is what one finds on the spec sheets.
>>|
>>| cheers
>>|
>>| - Rich..., 805.386.3734, www.vcnet.com/measures.
>>|
>
>- Rich..., 805.386.3734, www.vcnet.com/measures.
>
>
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