[Collins] 572B and the 30L1

[k6xyz]

The RF Parts website states that the Taylor Select 572B tubes have the
elements properly aligned for horizontal operation in the 30L-1.
They are probably Chinese too.
They sell a different 572B as well for upright installations.

Regards

Dave Harmon
CCA 97-535
K6XYZ[at]sbcglobal[dot]net
Sperry, Ok.

-----Original Message-----
From: collins-bounces at mailman.qth.net
[mailto:collins-bounces at mailman.qth.net] On Behalf Of w9hak
Sent: Thursday, March 29, 2007 10:20 AM
To: Glen Zook
Cc: Collins Radio Assn; roy.morgan at nist.gov
Subject: Re: [Collins] 572B and the 30L1

I second that Glen, these tubes have the plate alignment correct. One of 
the RCA 811's I took out of service had the plate about 15 degrees from 
vertical. They were code dated 1963. But as you point out, horizontal is 
just asking for trouble.

 Smith Bradford
W9HAK


Glen Zook wrote:
> Be VERY careful when using Chinese 572B tubes in
> amplifiers like the Collins 30L-1 and the Heath SB-200
> which have the tubes mounted horizontally. 
> Unfortunately, the Chinese tubes do not always have
> the tube elements mounted in the same plane as the
> original Taylor and other U.S. manufactured tubes. 
> The unfortunate result of this is that the elements
> often "sag" and short out taking power supply
> components with them.
>
> The Russian tubes generally do not suffer from this
> defect and they are MUCH safer to use in amplifiers
> with the horizontally mounted tubes.
>
> Glen, K9STH
>
>
> --- w9hak <w9hak at insightbb.com> wrote:
>
> I just installed the 572B in my 30L1. They tune the
> same as the 811's. I was able to install them via the
> top cover after unplugging the amp. The Chinese 572B's
> have a slightly longer guide pin and may not pass
> through the chassis hole. Enter the Dremel tool, just
> nip off  the amount required to get the tube to pass
> thought the chassis opening.
>
>
>
>
>
>
>
>
>
> Glen, K9STH
>
> Website:  http://k9sth.com
>
>
>  
>
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