Mic Kaczmarczik's TubeInformation - The Blue Guitar
Mic Kaczmarczik's TubeInformation - The Blue Guitar
Mic Kaczmarczik's TubeInformation - The Blue Guitar
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From robertc908@aol.com Sun Jan 18 10:20:14 CST 1998<br />
Article: 51415 of rec.audio.tubes<br />
Path: geraldo.cc.utexas.edu!cs.utexas.edu!newspeer.sprintlink.net!news.sprintlink.net!Sprint!newsfeed.internetmci.com!152.163.199.19!portc03.blue.aol.com!audrey01.news.aol.com!notfor-mail<br />
From: robertc908@aol.com (RobertC908)<br />
Newsgroups: rec.audio.tubes<br />
Subject: Sylvania answer to "<strong>Blue</strong> Light in Tubes"<br />
Date: 17 Jan 1998 13:51:52 GMT<br />
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<strong>The</strong> following quote is from a small book by Sylvania entitle "Radio Tube Hints"<br />
volume one dated 1943.<br />
Quote<br />
Three Reason for <strong>Blue</strong> Glow<br />
Many inquires are received relative to the blue glow which is present in a<br />
number of Sylvania Tubes. Most of these are based on the misunderstanding of<br />
the different types of glow that may be present in a tubes. <strong>The</strong>re are three<br />
different types of blue haze that may appear while tubes are in operation. <strong>The</strong><br />
are classed as: Fluorescent glow; Mercuty Vapor Haze; Gas.<br />
<strong>The</strong> fluorescent glow is usually of violet color, and is noticable around the<br />
inside surface of the glass blub. This glow is a phenomenon caused by<br />
electronic bombardment taking place within the tube. This glow changes with<br />
the intensity of the signal and may at time become quite brilliant.<br />
Fluorescent glow has absolutely no affect on the operation of a receiver. In<br />
fact, tubes with this characteristic are particularly good as regards gas<br />
content.<br />
Mercury vapor haze is a blue glow which is noticeable between the plate and<br />
filament in Types 82 and 82 rectifier tubes. <strong>The</strong>se are the only types of<br />
Sylvania receiving tubes in which this type of haze appears. <strong>The</strong> perfect<br />
operation of Types 82 and 83 is dependent upon a mercury vapor which comes from<br />
free mercury that has been placed in the bulb during the exhaust period.<br />
<strong>The</strong>refore this type of blue haze is in no way detrimental to the operation of<br />
these tubes.<br />
Gas is a blue haze which is usually confined to the vicinity of the plate and<br />
filament structure. Its presence, when of large content, affects the operation<br />
of a receiver to the extent that erratic performance is noticeable. Gaasy<br />
tubes should always be replaced with new tubes.<br />
Testing for the above conditions can be best accomplished by actual operation<br />
in a receiver. It is not necessary to test for the blue glow evident in Type<br />
82 and 83, since this is characteristic of these two tubes.<br />
When in doubt as to the blue content of other types of tubes a sure test can be<br />
made by using a strong magnet next to the blub. A gaasy tube will not be<br />
affect in any way by the presence of the magnet, while the fluorescent glow,<br />
which has no affect on the performance of the tube, will shift about as the<br />
magnetic filed is shifted.<br />
Unquote<br />
<strong>The</strong> above blue glow explanation is Sylvania's and is for your information.<br />
It is not to rebuke anything someone else has stated.<br />
Also if your are interested here is the table of contents for this volume of<br />
Radio Tube Hints. This is the only volume I have according to the cover there<br />
must have been additional volumes.<br />
Table of contents:<br />
Converter Tube Design Features.