Thats the first Ive ever heard of that, better tell the old BC engineers who
just used what came in the door.
OTOH, in parallel you are dealing with a single bias supply or lack therof
for zero bias. Matching became important since sweep tubes were all over the
place as were also RCA's 8122 disaster. With varying bias requirements for
the same idle current matching was needed to keep one tube from running away
to quick destruction.
Good transmitting tubes are built to repeatable tolerances that dont require
matching. Ive yet to find a need for matched 572B's from China even in a 4
tube amp. The quickest way to destruction is to keep using the old parasitic
suppressors, its simple to build much better ones and with no voodoo science
involved....get the parts from Mouser for a few bucks.
With 3-500Z's its the same, they dont need matching. Any uneven color is
usually uneven cooling, especially in a Heathkit. A slight real difference
is unimportant,tantalum plate 3-500Z's should be run with a little color
anyway for longevity.
Carl
KM1H
----- Original Message -----
From: "Al Kozakiewicz" <akozak@hourglass.com>
To: <amps@contesting.com>
Sent: Wednesday, January 19, 2011 10:26 AM
Subject: Re: [Amps] 572Bs
> In any realistic parallel application. matching is not important. You
> match tubes for gain in a push-pull configuration to ensure linearity as
> each tube only conducts for half a cycle.
>
> Al
> AB2ZY
>
> ________________________________________
> From: amps-bounces@contesting.com [amps-bounces@contesting.com] On Behalf
> Of Paul Manuel [k4pdm@yahoo.com]
> Sent: Wednesday, January 19, 2011 8:26 AM
> To: amps@contesting.com
> Subject: Re: [Amps] 572Bs
>
> --- On Wed, 1/19/11, Randall, Randy <Randy.Randall@uchealth.com> wrote:
>> Got mine from RF parts. Matched
>> quad for a Ameritron 811A. Working no issues.
>
> Thanks, Randy. That brings up another question, is matching important in
> grounded grid operation (a Clipperton L?) I read somewhere that it is not.
>
> 73, Paul K4PDM
>
>
>
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