Craig,
My guess is they lowered the anode voltage and current on each tube to help
with the IMD problems. Running sweep tubes at 1100 to 1200 Vdc sure isn't a
good idea as that's over their maximum rating. Around 900 Vdc at the most for
tubes like a 6LF6, etc. Smaller sweep tubes (6LQ6, 6JE6, ect) ought to be ran a
little less. I ran a quantity of eight 8908's or M-2057's G-G to get 1500+ kW
PEP out of a sweep tube amp using 900 Vdc on the anodes. They were capable of
300 watts PEP each being grid driven. The 8950 or 6LF6 was some amount less,
around 175 to 200 watts each grid driven. I built one using two of the EL519's
(6KG6A), and the most I could squeeze out of that little grid driven amp was
about 300 watts PEP, so figure them at 150 watts PEP out each maximum. Running
them G-G would probably yield a less on AM, but about the same with SSB. That's
just from my expeirence with them. I'd like to see the article my self and see
what tubes and voltages they used.
Best,
Will
*********** REPLY SEPARATOR ***********
On 7/7/06 at 11:50 PM zdtech wrote:
>Hi Dick
>
>Most interesting, i just wonder how they went about improving the
>terrible IMD from Sweep tubes? It would be great if the same technique
>could be used with some better quality transmitting tubes. What
>magnitude of improvement in 3rd order IMD could the author of the
>article achieve? I look forward to reading about it.
>
>Craig
>VK3HE
>
>
>Dick Hanson wrote:
>> It is a combination of TV sweep tubes with a HV switching supply.
>> Pretty decent 3rd and 5th order distortion products.
>> It only works on frequencies below 20 meters. It is quite small.
>> That's about it.
>> 73
>> Dick, K5AND
>>
>> -----Original Message-----
>> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
>> Behalf Of zdtech
>> Sent: Friday, July 07, 2006 8:22 AM
>> To: amps@contesting.com
>> Subject: [Amps] QEX Innovative Tube Linear?
>>
>> Anyone receive their July/August copy QEX? There is an article in there
>> called "A Innovative Tube Linear" I am just wondering what is so
>> innovative about the linear? My issue of QEX arrives quite late after
>> the US publication date, so i was wondering if its something to look
>> forward too.
>>
>> Craig
>> VK3HE
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>>
>>
>
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