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
Envoyé : 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
Envoyé : 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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Re: Drake L-7
Thanks Dave.
Always “good” to hear the issues!
In the L7 the RFC3 was ok (no issues in 15 years)
73, Evert
PA2KW <https://www.qrz.com/db/PA2KW> / 5T2KW <https://www.qrz.com/db/5T2KW>
By
Evert Bakker
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#40983
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Re: Drake L-7
I've just bought 4 from W8JI at CTR Engineering. Installed one in my AL-1500 and one in my home brew 2 x 3-500Z 160 to 10 amp. No problems on any band with those chokes.
73, Alek VK6APK.
By
Alek Petkovic
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#40982
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Re: Drake L-7
I found the RF-choke I used :
https://www.rfparts.com/rfc3.html
Thanks
225 ?H; that's a big value indeed. I thought you wound it yourself on the original mandrel.
Why did you have to
By
Fran?ois
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#40981
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Re: Drake L-7
From my own experience in blowing up two of those, is that RFC3 RF-choke purchased from RF-Parts is resonant on 30 meters when used in a 3-tube (8874) Alpha 76A amplifier. Use in other amplifiers may
By
Dave w6de
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#40980
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Re: Drake L-7
I found the RF-choke I used :
https://www.rfparts.com/rfc3.html
73, Evert
<https://www.qrz.com/db/PA2KW> PA2KW / <https://www.qrz.com/db/5T2KW> 5T2KW / W8S
By
Evert Bakker
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#40979
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Re: Drake L-7
Francois,
** Your capacitor 'A' went with your old RF choke.
Yes, you are correct.
73, Evert
<https://www.qrz.com/db/PA2KW> PA2KW / <https://www.qrz.com/db/5T2KW> 5T2KW / W8S
By
Evert Bakker
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#40978
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Dentron DTR-2000L info
Hi All,
I have a DTR-2000L that I'm trying to bring back to life.? It's the same one that I asked about last year.? What I'd like is IF someone that has one of these amps, that's working, would you
By
Kim Herron
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#40977
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