I think I get Richs point.
Introduced by EIMAC in 1957 in an amplifier application using a 4CX1000, a
50 ohm dummyload was connected at the input of the grounded cathode tube.
The advantages are:
1.the exciter always is always connected to 50 ohms although you have to
compensate for the effects of input capacitance at the higher short wave
bands
2. no input filters
3.a more stable amp
This solution is used in several of the latest amplifiers using high gain
Russian tubes like the GU 74. By adding a undecoupled resistor beetween
cathode and ground, they get some negative feedback and lower distorsion.
This technique comes also from EIMAC in an 4CX600FJ application. Look at the
SVETLANA data sheet for the 4CX1600.
Prosit de Hans
----------
>Från: "Randall D. DuCharme" <randyd@specent.com>
>Till: measures <2@vc.net>
>Kopia: amps@contesting.com
>Ämne: Re: SV: [AMPS] possible amp tube
>Datum: lör 18 nov 2000 17.06
>
>
>Hi Rich, and group;
>
>measures wrote:
>
>> G-G is not very suitable for a 9-band amplifier. Tetrodes and Pentodes
>> in AB1 are.
>
>I'm not sure I understand what you mean here. Do you mean grids
>strapped to ground, or does G-G mean grounded grid with respect to rf?
>(ie: rf-bypassed but with proper screen voltage and bias)
>
>
>Thanks
>
>--
>Randall D DuCharme (KD5IZI) Proud to be 100% Microsoft Free!
>
>Unsolicited commercial email (SPAM) received at this email address
>will not be tolerated. All spam is subject to a $200 per incident
>processing fee and possible legal action pursuant to US Code, Title
>47, Chapter 5, Subchapter II, p.227.
>
>--
>FAQ on WWW: http://www.contesting.com/FAQ/amps
>Submissions: amps@contesting.com
>Administrative requests: amps-REQUEST@contesting.com
>Problems: owner-amps@contesting.com
>
>
--
FAQ on WWW: http://www.contesting.com/FAQ/amps
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
|