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Author
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Topic: Troubled Twin Reverb
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Jim Smith
Member From: Plano, TX, USA
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posted 12 November 2001 10:34 AM
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quote:
There are standby switches on solid state amps as well as tube types.
Why, and on what transistor amps?  |
Bob Carlson
Member From: Surprise AZ.
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posted 13 November 2001 02:42 PM
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Blake Hawkins,
you say you like my comment about the flakes from the cathode falling to the bottom of the tube.And have I looked at the way the tubes are mounted in my Fender Twin? They are upside down! When a light bulb is screwed in, is it upside down? Wouldn't that be the ideal place (it can't get to the top) for the flakes to fall? Same ideal place for them to fall with a tube. What I meant by the last part was, the power amps at the station were on 24 hours a day and you said the tubes lasted for years, isn't that tellig us something?. Enough said from me, i got better things to do. Bob Carlson.
[This message was edited by Bob Carlson on 13 November 2001 at 02:54 PM.] |
Blake Hawkins
Member From: Land O'Lakes, Florida
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posted 14 November 2001 06:59 AM
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Bob Carlson,
I'm sorry, I didn't realize that you were unfamiliar with the differences between the construction of a light bulb and a vacuum tube.
In a light bulb the filament is located in the center of the bulb...there is nothing above or below it so if something falls and goes to the top or bottom it makes no difference.
A vacuum tube has many more elements;heater, cathode, grid or grids and plate or plates.
These are all mounted vertically on a support structure. At the bottom, the elements are supported by the glass seal or in come cases a reinforcing bead. At the top there is a support insulating element which holds the elements apart and adding strength. This is usually a mica washer.
If the tube is burned base down and something flakes off...it will fall into the base and probably cause no more trouble as long as the tube is not moved.
If the tube is burned upside down with the base up, then a piece falling material could be stoped by the mica washer and vibration and such cause a short or a degradation of the performance.
Also, a guitar amp is a special case in that it is moved frequently, tumbled, and bounced around. Anything that is loose will wind up causing trouble.
My point was not to attack you, but to point out, that whoever originally made that statement did not understand vacuum tubes nor their special use in guitar amplifiers.
Sorry if I am wasting your time...just trying to bring some understanding to an otherwise arcane subject.
Blake |
Paul Graupp
Member From: Macon Ga USA
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posted 14 November 2001 07:12 AM
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Still makes interesting reading, Blake. And a refresher course is always good for the memory factory. I'd say you are right on !!Regards, Paul  |
Blake Hawkins
Member From: Land O'Lakes, Florida
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posted 14 November 2001 08:17 AM
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Thanks Paul!
I have a question for you....Did you ever work with Curley Williams or Paul Howard?
I am originally from Georgia and was a fan of Slim Idaho. Did you know him?
Doug Seymore and I have been trying to pinpoint which year Slim had his fatal traffic accident. Do you by any chance remember?
Thanx
Blake |
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