[Amps] IM distortion and such

[Peter Chadwick]

Ken said:
>As I recall, it was an attempt to fill a gap between the bigger and more 
expensive Eimac offerings and the 811A offered by everyone.  Also, if I 
remember correctly, it was specifically created as an amateur service 
tube as was the 3-1000Z.  Interestingly enough, the 572B is still with 
us, but the 3-1000Z, with its much more elegant structure, is long 
gone. <

Ken, tnx for that. The 572B does seem a peculiar approach, though, because it would have been quite easy at that stage to have used a structure that provided a much shorter grid lead - the 826/832/829/7094 style construction, for example. The 832 (or even 5894) style base can't have been that expensive by the mid 1950's, considering the number that had been made by then. Looking through the ARRL Handbook tube data as it changed year by year, it does seem that the 572B appeared about the time of the 30L1, which,  so it is said, appeared because an engineer at Collins who was a ham, built one for home use as an experiment. And what happened to the 572 and the 572A - or did they ever exist? Who made the 572B other than Cetron? What else did they make, and does anyone know who they really were?
It's a bit frightening in a way, that things happened within the ham lifetime of many of us, are almost lost in historical terms!
73
Peter G3RZP




========================================
Message Received: Jun 28 2006, 12:23 PM
From: "Kenneth D. Grimm, K4XL" 
To: g3rzp at g3rzp.wanadoo.co.uk
Cc: "Tom W8JI" , amps at contesting.com
Subject: Re: [Amps] IM distortion and such

Peter Chadwick wrote:
> (a bunch of technical stuff in reply to Tom snipped)
> Slightly off topic, I never understood where the 572B came from for linear service. It seemed to appear in the 1950's: I sort of assume as a bigger modulator tube, being a pair of 811A, but that seems a bit late in the day for a purely audio tube. If designed as an RF tube, it surely would have been given a better structure?
> 73
> Peter G3RZP
> _______________________________________________
As I recall, it was an attempt to fill a gap between the bigger and more 
expensive Eimac offerings and the 811A offered by everyone. Also, if I 
remember correctly, it was specifically created as an amateur service 
tube as was the 3-1000Z. Interestingly enough, the 572B is still with 
us, but the 3-1000Z, with its much more elegant structure, is long 
gone. Sometimes the engineers get it right, but the bean counters get 
it righter. :-)

73,

-- 

Ken K4XL
k4xl at arrl.net

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