[Collins] 572B and the 30L1
w9hak
w9hak at insightbb.com
Thu Mar 29 10:20:03 EST 2007
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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