[Amps] Tube swap

[Carl]

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 at bmts.com>
To: "Hardy Landskov" <n7rt at cox.net>; "Fuqua, Bill L" <wlfuqu00 at uky.edu>; 
"Jack Taylor" <jack at n7oo.com>; <amps at 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 at cox.net>
> To: "Fuqua, Bill L" <wlfuqu00 at uky.edu>; "Jack Taylor" <jack at n7oo.com>; 
> <amps at 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 at uky.edu>
>> To: "Jack Taylor" <jack at n7oo.com>; <amps at 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 at contesting.com] on behalf of Jack Taylor 
>>> [jack at n7oo.com]
>>> Sent: Monday, January 27, 2014 3:51 PM
>>> To: amps at 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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>>
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