[Collins] 6DF5 pin #7 not used in 75S3B?

Fri, 10 Jan 2003 15:44:04 -0500

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Dave, W3ST
Secretary to the Collins Radio Association
www.collinsra.com

----- Original Message ----- 
From: <[email protected]>
To: <[email protected]>
Cc: <[email protected]>; <[email protected]>
Sent: Friday, January 10, 2003 2:49 PM
Subject: Re: [Collins] 6DF5 pin #7 not used in 75S3B?

> HI DOCTOR JOHNSON. Re shielding, where can one get mumetal for that kind
> of a shield?
> jack..
> 
> On Fri, 10 Jan 2003 11:08:42 -0600 "Dr. Gerald N. Johnson, electrical
> engineer" <[email protected]> writes:
> > The tube grid is hooked to both 1 and 7. Doesn't matter which is 
> > wired
> > at the socket.
> > 
> > I found background AC hum in my 75S3B from hum modulating the noise
> > through the mechanical filter. I added a magnetic shield to cure 
> > that
> > back about 1965. The other hum source was a little heater cathode
> > leaking in the notch Q multiplier tube.
> > 
> > 73, Jerry, Technical Advisor to the CRA.
> > 
> > -- 
> > Entire content copyright Dr. Gerald N. Johnson, electrical 
> > engineer.
> > Reproduction by permission only.
> > Sponsored by the Collins Radio Association
> > http://www.collinsra.com
> > 
> > 
> Sponsored by the Collins Radio Association
> http://www.collinsra.com