Hardy,
yes I made myself a Hi-pot tester as well. I forgot the specs, but I believe
I can go up to 20 kV. (It may be one of Richard Measures designs). I also
have a Hi voltage electrostatic voltmeter from a research lab. It can go up
to some 20-50 kV (sorry I might be off few kV). I used to work on HV testing
Power transformers for lightning tests and studied HV at the university, so
I do have some experience with HV, although it was now some 30-40 years
ago....
(When I manage to get inside the shed I will take some pictures of my HV
setup to get some comments from you guys.There is always lot to learn).
I will try your suggestion and will test all tubes.
I was planning to hi-pot test everything before I would switch the amp on.
Karel Ebenstreit, VA3KO
----- Original Message -----
From: "Hardy Landskov" <n7rt@cox.net>
To: "Karel" <kebenstr@bmts.com>; "Carl" <km1h@jeremy.mv.com>;
<amps@contesting.com>
Sent: Monday, January 27, 2014 10:18 PM
Subject: Re: [Amps] Tube swap
Karel,
I use a Hi-Pot tester made from a neon sign transformer and a few extra
parts. The one I just will go to 8 kV and unfortunately, found one of
my best? vacuum variables strarted arcing at 6.5 kV. You can use the
device by conneting plate to grid and increaseing the variac until arcs
start to happen--hopefully not.
73 Hardy N7RT
----- Original Message -----
From: "Karel" <kebenstr@bmts.com>
To: "Carl" <km1h@jeremy.mv.com>; <amps@contesting.com>
Sent: Monday, January 27, 2014 7:56 PM
Subject: Re: [Amps] Tube swap
How do you check if they leaked?
Should there be a whitish discoloration inside the tube?
I will check mine later next month. Right now my amp stuff in under 4
feet of snow here in western Ontario.
Karel, VA3KO
----- Original Message -----
From: "Carl" <km1h@jeremy.mv.com>
To: "Karel" <kebenstr@bmts.com>; <amps@contesting.com>
Sent: Monday, January 27, 2014 9:17 PM
Subject: Re: [Amps] Tube swap
People are still running HB 4X1 amps and others continue to build when
the tubes have been on hand for ages or can be found cheap.
The big problem, even with NIB, is the seals leak and the tube slowly
goes to air.
Carl
KM1H
----- Original Message -----
From: "Karel" <kebenstr@bmts.com>
To: "Hardy Landskov" <n7rt@cox.net>; "Fuqua, Bill L" <wlfuqu00@uky.edu>;
"Jack Taylor" <jack@n7oo.com>; <amps@contesting.com>
Sent: Monday, January 27, 2014 8:08 PM
Subject: Re: [Amps] Tube swap
I still have 5 tubes, 4-1000A, 2 of them never used, 3 used ones, is
there still demand for these?
I started an amp (2 tubes). So far I did not finish the project yet,
not sure if I will. Perhaps if I go with 1 tube only.
Karel Ebenstreit, VA3KO
----- Original Message -----
From: "Hardy Landskov" <n7rt@cox.net>
To: "Fuqua, Bill L" <wlfuqu00@uky.edu>; "Jack Taylor" <jack@n7oo.com>;
<amps@contesting.com>
Sent: Monday, January 27, 2014 5:58 PM
Subject: Re: [Amps] Tube swap
In addition to Bill's list, it will take about 30 to 40% more drive.
Been there, done that.
GL Hardy N7RT
----- Original Message -----
From: "Fuqua, Bill L" <wlfuqu00@uky.edu>
To: "Jack Taylor" <jack@n7oo.com>; <amps@contesting.com>
Sent: Monday, January 27, 2014 1:57 PM
Subject: Re: [Amps] Tube swap
Yes and no.
1. The 4-1000A is taller so the chimney may not fit.
2. The 4-1000A in grounded grid will require more plate voltage to
achieve the same output.
3. The input impedance of the 4-1000a is a bit higher so you may have
to make some changes to your input matching ckt.
4. The control grid pin needs to be grounded as well as screen grid
pins.
5. The output Z of the 4-1000A is higher but not so much that most
plate tank circuits can't deal with it.
73
Bill wa4lav
________________________________________
From: Amps [amps-bounces@contesting.com] on behalf of Jack Taylor
[jack@n7oo.com]
Sent: Monday, January 27, 2014 3:51 PM
To: amps@contesting.com
Subject: [Amps] Tube swap
Am in the process of bringing back to life a RF 102A. Should the
3-1000Z
turn out to be defective, can I directly
interchange it with a 4-1000A?
Jack - n7oo
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