[R-390] Fwd: Re: Alternative to IERC tube shields?

[odyslim at comcast.net]

 I have not been following this thread so please excuuuuuse me if this
has already been discussed.

 I think it is better to leave some tubes unshielded to see the condition
of the tube itself in service.

 I was pondering the thought of using a special metal tape used on heavy
truck exhaust systems. It is the perfect width to wrap around a 6082 for 
example and then tape it to the chassis. Let the heat dissipate onto the
chassis and everybody is happy. This is a very heavy metal tape. It then 
dawned upon me that I rely on looking at that 6082 to see what is going
on inside that hot tube. I have often HEARD something odd in the R390 
audio, then looking over to the 6082's to see a blue storm blasting away
inside one of the tubes. Then suddenly a quick glance over to the left 
and the same is happening to one of the 26Z5W's. After spending a weeks
lunch money on new tubes, I have learned to let those tubes go NAKED.

 

Regards, Scott

----- Original Message -----
From: Tim Shoppa <tshoppa at wmata.com>
To: Osamu Hazawa <pomerol at mocha.ocn.ne.jp>, R-390 at mailman.qth.net
Sent: Mon, 17 Aug 2009 12:59:28 +0000 (UTC)
Subject: Re: [R-390] Alternative to IERC tube shields?

> Considering the increased price for the IERC tube shields, can it be an
> alternative?
> Your thought?

Perhaps if IERC's are not a available, a better alternative for the
vast majority of tubes that don't actually need shielding, is no shield.

I agree that the IERC's are great if you've got them. I've picked some
Up over the years from hamfests etc. but that can be a painfully way slow
To get to the quantities needed for a 390A.

I am slowly learning sheet metal techniques and have worked my way
up to "make a chassis box". While I lack the skill, I think the thermal
and moral equivalent of an IERC tube could be reproduced by a
sufficiently enthusiastic hobbyist. As it is, though, it's usually
way more fun to mess around with radios and electronics than it is
to do sheet metal stuff (although it is highly satisfying when I actually
get the round tuit and do sheet metal stuff.)

IERC cans appear to be seamless, so they were probably deep drawn?
Is this likely the same process used to make the deep unseamed metal
Capacitor cans?

Tim N3QE
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