Re: Drake L-7
The 3-500zg tube with the graphite plate can handle 600ma ICAS ? The regular 3-500 rated 450ma CCS! ?With enough cooling (very important factor) you could run 2000 watts pep output SSB with a pair
By
Louis Parascondola
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#41003
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Re: Drake L-7
The original? C41 cap (47 pf) is failure prone.? ?Replace it with a 50 pf TX doorknob cap.? ?The original cap? was made from pc board.
C42? ( 307 pf)? is used to pad the TUNE cap on 160m
By
Jim VE7RF
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#41002
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Re: Commander HF-2500 Plate Choke
The 3 x section choke,? currently sold by ameritron,? is now screwed up.? Ameritron ran outa 28 ga wire...and started using 27 ga wire.? ?The pair of gaps is way less.? Steve at RF parts got a
By
Jim VE7RF
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#41001
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Re: Drake L-7
Hello
Thank you for this communication.
Even if it does not answer my question, this document is very interesting, both at the technological and implementation level.
I reformulate my
By
Fran?ois
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#41000
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Re: Commander HF-2500 Plate Choke
Dear Riki,
Tom, W8JI,
By
HaL Mandel
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#40999
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Re: Drake L-7
Dear Francois,
Attached, please find a great book about tubed amplifiers.
'73,
Hal Mandel
W4HBM
By
HaL Mandel
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#40998
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Re: Drake L-7
I am still studying a way to cook my 3-500Z which have not been hot for at least 15 years. The idea is to cook at high current with a low anode voltage, without HF.
The maximum rating of the
By
Fran?ois
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#40997
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Re: Drake L-7
Yes, a ¡°single diode path¡± would have made it clearer.
Thanks for the clarification. What I understood is that these diodes are used to protect the galvanometers in the event of an arc in the
By
Fran?ois
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#40996
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Re: Commander HF-2500 Plate Choke
Hi Riki
I own a 1990 HF-2500 which I got from the estate of a local ham many years ago. I had a question about it on this forum last week but through perseverance and much hair pulling, I managed to
By
Alek Petkovic
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#40995
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Commander HF-2500 Plate Choke
Somebody who previously owned my Commander HF-2500 replaced the carbon resistors in the plate parasitic chokes with a different type of resistor.? This worked fine on low frequencies 160M, 80M, and
By
Riki, K7NJ
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#40994
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Re: Drake L-7
Yes, a ¡°single diode path¡± would have made it clearer.
Here more then 0.7V are clamped, depends on the meter or meter shunt for
grid current.
Zener diode can be used as well or a germanium
By
Peter Voelpel
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#40993
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Re: Drake L-7
http://radiojim.exofire.net/pages/Glitch%20diodes.html
--
F1AMM
Fran?ois
De la part de Peter Voelpel
Envoy¨¦ : mercredi 29 janvier 2025 18:37
By
Fran?ois
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#40992
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Re: Drake L-7
That clamp diode is typically a single diode.
73
Peter, DJ7WW
-----Original-Nachricht-----
Betreff: Re: [ham-amplifiers] Drake L-7
Datum: 2025-01-29T13:33:50+0100
Von: "Jim VE7RF
By
Peter Voelpel
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#40991
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Re: Drake L-7
Does the following diagram correspond to your proposal?
What is the green diode used for?
--
F1AMM
Fran?ois
De la part de Jim VE7RF via groups.io
Envoy¨¦ : mercredi 29 janvier 2025
By
Fran?ois
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#40990
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Re: Drake L-7
A diode clamp is simply? a pair of REVERSE connected diodes, like 1N5408 / 6A10 / PM-600? type diodes.? ?They are wired between the B-? and the chassis.? Then the B- can never wander more than
By
Jim VE7RF
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#40989
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Re: Drake L-7
https://www.w8ji.com/vacuum_tubes_and_vaccum_tube_failures.htm
Anode systems should have series-resistance to limit peak current in the event of a tube arc or failure. That series resistance
By
Fran?ois
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#40988
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Re: Drake L-7
No problem Hal!
73, Evert
<https://www.qrz.com/db/PA2KW> PA2KW / <https://www.qrz.com/db/5T2KW> 5T2KW / <https://www.qrz.com/db/W8S> W8S
Sent: Tuesday, 28 January 2025 18:14
To:
By
Evert Bakker
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#40987
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Re: Drake L-7
Gentlemen,
My apology.
I was thinking you were talking about Grid
Bypass circuits of caps and chokes instead
of Anode Bypass.
As a compliment, the W8JI program of
analyzing and preparing Anode
By
HaL Mandel
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#40986
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Re: Drake L-7
Dear Everett et al,
There are those that believe a Pi-Wound, or even
a Solenoid-Wound inductor is the Saving Grace of
QRO amplifiers.
And there are those who think that monsters are
really hiding in
By
HaL Mandel
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#40985
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Re: Drake L-7
I was told that the original RF-choke could cause oscillation.
73, Evert
PA2KW <https://www.qrz.com/db/PA2KW> / 5T2KW <https://www.qrz.com/db/5T2KW> / <https://www.qrz.com/db/W8S> W8S
By
Evert Bakker
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#40984
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