[R-390] Some interesting info.

Thu, 11 Jul 2002 19:49:21 -0400

Hey Norm, I want to thank you for your 390 non-a tube list that
you posted May 30.  I printed it out this morning.  I was going to
compile the list myself but you saved me the work.  :-)  Thanks!!
I am particularly interested in the subbing of 5814a's for
12au7's.  I get the 5814a's for  $3.50 (NOS)  from my dealer but the damn
12au7's are going for $12.00 each.  That is a LOT of money for an
inferior tube!!  Oh, there I go again.  I am going to have my mailbox jambed
'cause I called a 12au7 inferior.  I have not looked into it, but I would
guess
all 12au7's could be subbed with 5814a's if equalizing resistors were used
to
balance the current properly through  each tube in the string.  This would
be a
BIG $$$$ savings in tubes.  What do you  think??

Scott

----- Original Message -----
From: "Norman Ryan" <[email protected]>
To: "scott" <[email protected]>
Cc: <[email protected]>
Sent: Thursday, July 11, 2002 7:02 PM
Subject: Re: [R-390] Some interesting info.

> Hi, Scott,
>
> Thanks for passing this on.  VERY enlightening.  Barry Ornitz is one
> smart guy.
>
> This is good material for the R-390A FAQ pages.  Al T., are you reading
> this?
>
> 73 de Norman KG4SWM
>
> scott wrote:
> >
> > I thought this was a really good post on cap
> > longevity.
>
> >
> > From: "Barry L. Ornitz" <[email protected]>
> > To: Old Tube Radios <[email protected]>
> > Subject: Re: Capacitor lifetime & a little info on new materials
> > Date: Wed, 29 May 2002 19:34:26 -0400
> >
> > Having spent most of my career involved in manufacturing
> > polyethylene terephthalate polyester (PET, Mylar� is
> > DuPon'ts variety), polypropylene (PP) and
> > polytetrafluoroethylene (PTFE, Teflon� is the most common
> > variety), and been involved in a few research projects on
> > other newer materials occasionally used in capacitors such
> > as polyphenylene sulfide (PPS), polyethylene naphthalate
> > (PEN), and cyclohexane dimethanol modified polyester
> > (PETG), I think I can address this issue.  I also am
> > familiar with polystyrene (PS) and polyphenylene oxide
> > (PPO) materials.
>
> Rest of text snipped.
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