[Boatanchors] Octal Metal Tubes

Wed, 12 Nov 2003 07:01:45 -0600

I just ran across that "MR" term within the past week.  Since it was on a
2A5, I thought, hmmm...who better to ask than the *ahem* audiophiles?:  Had
an answer in about a half hour on rec.audio.tubes:

"Maintenance & Repair. It was done during the last couple of years
of WW2, to set aside a certain percentage of tube production for
civilian use.  The idea was that once the tubes were branded MR, they
couldn't be diverted to a military contract that theoretically had a
higher priority rating".

Makes sense to me.  Anyone?

73,
Tom

----- Original Message ----- 
From: "Bill Pileggi" <[email protected]>
To: <[email protected]>
Sent: Tuesday, November 11, 2003 11:56 PM
Subject: [Boatanchors] Octal Metal Tubes

>
> I have an octal metal tube (currently in use), specifically an RCA 6SK7
which is stamped "Sub-standard M-R". It's printed with the same ink as the
rest of the legends. The "M-R" is twice as high as the rest of the
lettering. Does this message have any significance? Bill KA3AIS
>
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