Tubes Asylum

RE: KT77s...

108.67.99.242

Steve O

A

In Reply to: RE: KT77s... posted by unclestu on February 16, 2014 at 13:12:06

Interesting take on the design of the mica spacers.

I always looked at the metal fingers as the primo method of locating the electrodes in the envelope. The first (and best IMO) 807s used the fingers as did the original metal base RCA 7027. And then there were the Bendix "Red Bank" series of tubes that used metal things well evolved beyond fingers that were used to locate the ceramic discs used in place of mica. If metal fingers were good enough for 60s era nukes, who am I to argue?

Follow Ups:

RE: KT77s... - unclestu 13:24:41 02/19/14 (0)
That's not what Morrison told me: Metal fingers were the cheapest way to make a centering system.

Later RCA 7027 used a mica centering mechanims, So did other premium 6L6's including EL37's and 5881's. Most of my 807's including the milspec 5932 uses mica as the centering device.

As for the Bendix, theirs is a metal spring tensioner, very much more complex than the simple fingers used by most others. In tandem with their extremely thick ceramic spacing element in lieu of the mica, it was much more expensive to produce and probably exerts a lot more centering spring action.

The role of the mica sheets are often overlooked, by consumers. Take a careful look at most JAN tubes: the common 5751 and 5814's are good examples. The mica sheets are much thicker than in the typical consumer
grade tubes, sometimes triple the thickness. These are obviously done for a reason.
Good to know. - jusbe 23:48:33 02/16/14 (0)
Not sure I would have noticed that heritage.

big j.

"... only a very few individuals understand as yet that personal salvation is a contradiction in terms."

Post a Followup:

FAQ

Post a Message!

Forgot Password?

Moniker (Username):
Password (Optional):
	Remember my Moniker & Password (What's this?) Eat Me
E-Mail (Optional):
Subject:

Message:	(Posts are subject to Content Rules)

Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:	Automagically notify you when someone responds.

To view your new posting or follow-up, click on the RELOAD or REFRESH button on your browser.

This post is made possible by the generous support of people like you and our sponsors:

VH Audio