[Amps] Replacement tube for 4-1000a

[Carl]

I guess it depends on what is meant by good. Used ones with gas can often be 
cooked at around 1000V and enough positive bias to get a nice glow to 
regetter. Run as a GG.

A chance incident this past summer yielded a NIB 4PR1000A and a slightly 
used 4-1000A for $20 and $10. I still need one more chimney.

Carl
KM1H


----- Original Message ----- 
From: "Bill Fuqua" <wlfuqu00 at uky.edu>
To: "Dennis Goebel" <radios1236 at yahoo.com>; <Amps at contesting.com>
Sent: Wednesday, December 08, 2010 3:33 PM
Subject: Re: [Amps] Replacement tube for 4-1000a


>I have a number of 4-1000A tubes. If you are willing to pay the price you
> can get new ones made by Amperex ( Covimag) which are more rugged than the
> EIMAC ones.
> I usually get them at hamfest and since I have my own portable tester I 
> can
> check them right there.
> The Amperex tubes have graphite plates and it is better supported than the
> EIMAC ones. I have often gotten EIMAC ones that were dropped in shipping
> and the anode bent off to one side. I have been able to straighten up
> almost all of them but it is a bit risky.  I think Triton has quit making
> them. They could never get the big glass triodes and tetrodes right.
>
> 73
> Bill wa4lav
>
> At 03:21 PM 12/8/2010 -0500, Dennis Goebel wrote:
>>I have found it increasingly difficult to locate good 4-1000a tubes. Just
>>wondering what would be a good replacement tetrode for the 4-1000a in grid
>>driven service. Not grounded grid.
>>Obviously it doesn't have to be the same socket or filament voltage as the
>>4-1000a.
>>It would be nice to come close to some of the other parameters so
>>recreation of the entire amp wouldn't be needed.
>>I have thought of the russian GS-23 or GU-74 series tetrodes. Or home
>>grown variety like 4CX1000 or the like. Most of these have pretty wimpy g1
>>and g2 parameters compared though.
>>Anyway I would like to get some opinions from the experts on the 
>>reflector.
>>thanks
>>Dennis
>>
>>
>>
>>
>>
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