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	<title>TubeSound &#187; Tubes</title>
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	<link>http://tubesound.com</link>
	<description>Vintage Audio Sales and Service</description>
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		<title>Testing VR (glow) tubes</title>
		<link>http://tubesound.com/2011/03/15/testing-vr-glow-tubes/</link>
		<comments>http://tubesound.com/2011/03/15/testing-vr-glow-tubes/#comments</comments>
		<pubDate>Wed, 16 Mar 2011 02:15:09 +0000</pubDate>
		<dc:creator>Bob</dc:creator>
				<category><![CDATA[Tubes]]></category>

		<guid isPermaLink="false">http://tubesound.com/?p=1045</guid>
		<description><![CDATA[©2011 Bob Putnak. I am frequently asked how to test voltage regulator (VR) tubes, which are sometimes called &#8220;glow regulator&#8221; or &#8220;glow discharge&#8221; tubes. Few tube testers test VR tubes, and most models that claim to test VR tubes do a worthless job at this task. They use AC voltages instead of DC the AC [...]]]></description>
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		<slash:comments>0</slash:comments>
		</item>
		<item>
		<title>NOS NIB NEW Arcturus Blue 071A tube (71-A)</title>
		<link>http://tubesound.com/2010/07/27/nos-nib-new-arcturus-blue-071a-tube-71-a/</link>
		<comments>http://tubesound.com/2010/07/27/nos-nib-new-arcturus-blue-071a-tube-71-a/#comments</comments>
		<pubDate>Tue, 27 Jul 2010 16:15:06 +0000</pubDate>
		<dc:creator>Bob</dc:creator>
				<category><![CDATA[Tubes]]></category>

		<guid isPermaLink="false">http://tubesound.com/?p=877</guid>
		<description><![CDATA[Here is something that you will not see everyday, an NOS NIB NEW Globe-style Arcturus blue-glass 071A audio output tube.  Type 071A is also known as 71-A, 71A, 171A, 271A, 371A. This tube has the star-logo on the top of the glass bulb with 071A inside the star logo. Engraved base reads &#8220;ARCTURUS &#8211; No. [...]]]></description>
		<wfw:commentRss>http://tubesound.com/2010/07/27/nos-nib-new-arcturus-blue-071a-tube-71-a/feed/</wfw:commentRss>
		<slash:comments>0</slash:comments>
		</item>
		<item>
		<title>when E283CC tubes are actually a 12AX7</title>
		<link>http://tubesound.com/2010/07/21/when-e283cc-are-12ax7/</link>
		<comments>http://tubesound.com/2010/07/21/when-e283cc-are-12ax7/#comments</comments>
		<pubDate>Wed, 21 Jul 2010 18:53:35 +0000</pubDate>
		<dc:creator>Bob</dc:creator>
				<category><![CDATA[Blog]]></category>
		<category><![CDATA[Tubes]]></category>

		<guid isPermaLink="false">http://tubesound.com/?p=874</guid>
		<description><![CDATA[This is one of many examples where tube testing requires experience to properly evaluate any tube.  In this situation, using a tube tester would yield a completely wrong answer. These tubes were factory marked as E283CC, but are actually 12AX7A tubes.  Hence, if you tested them in your tube tester using E283CC settings, you would [...]]]></description>
		<wfw:commentRss>http://tubesound.com/2010/07/21/when-e283cc-are-12ax7/feed/</wfw:commentRss>
		<slash:comments>0</slash:comments>
		</item>
		<item>
		<title>RMA Tube Numbering Code</title>
		<link>http://tubesound.com/2010/04/09/rma-tube-numbering-code/</link>
		<comments>http://tubesound.com/2010/04/09/rma-tube-numbering-code/#comments</comments>
		<pubDate>Fri, 09 Apr 2010 19:56:54 +0000</pubDate>
		<dc:creator>Bob</dc:creator>
				<category><![CDATA[Tubes]]></category>

		<guid isPermaLink="false">http://tubesound.com/?p=745</guid>
		<description><![CDATA[I am frequently asked to explain what all of the &#8220;letters and numbers&#8221; mean in a vacuum tube number.  In the early days of radio, tube numbers were haphazardly assigned to new tube types.  As more vacuum tube types were developed, it became more difficult for technicians to recognize any fundamental characteristics about a tube.  [...]]]></description>
		<wfw:commentRss>http://tubesound.com/2010/04/09/rma-tube-numbering-code/feed/</wfw:commentRss>
		<slash:comments>0</slash:comments>
		</item>
		<item>
		<title>Tube Testing &amp; How to Use a Tube Tester</title>
		<link>http://tubesound.com/2010/04/07/tube-testing-how-to-use-a-tube-tester/</link>
		<comments>http://tubesound.com/2010/04/07/tube-testing-how-to-use-a-tube-tester/#comments</comments>
		<pubDate>Thu, 08 Apr 2010 01:20:21 +0000</pubDate>
		<dc:creator>Bob</dc:creator>
				<category><![CDATA[Tube Testers]]></category>
		<category><![CDATA[Tubes]]></category>

		<guid isPermaLink="false">http://tubesound.com/?p=743</guid>
		<description><![CDATA[How to Use a Tube Tester&#8230; and Tube Issues (in General) by Bob Putnak, ©2010.  All rights reserved. Your tube tester is often the first test instrument that you reach for when diagnosing problems in tube gear.  All tube testers are a compromise in functionality, compromise in accuracy, and none are perfect.  No models test [...]]]></description>
		<wfw:commentRss>http://tubesound.com/2010/04/07/tube-testing-how-to-use-a-tube-tester/feed/</wfw:commentRss>
		<slash:comments>0</slash:comments>
		</item>
		<item>
		<title>Solid state replacement for #83 tube</title>
		<link>http://tubesound.com/2009/01/16/solid-state-replacement-for-83-tube/</link>
		<comments>http://tubesound.com/2009/01/16/solid-state-replacement-for-83-tube/#comments</comments>
		<pubDate>Fri, 16 Jan 2009 23:33:49 +0000</pubDate>
		<dc:creator>Bob</dc:creator>
				<category><![CDATA[Tube Testers]]></category>
		<category><![CDATA[Tubes]]></category>
		<category><![CDATA[83]]></category>
		<category><![CDATA[B&K]]></category>
		<category><![CDATA[Hickok]]></category>
		<category><![CDATA[replacement]]></category>
		<category><![CDATA[solid]]></category>
		<category><![CDATA[state]]></category>
		<category><![CDATA[tester]]></category>
		<category><![CDATA[tube]]></category>

		<guid isPermaLink="false">http://tubesound.com/?p=429</guid>
		<description><![CDATA[I am frequently asked by B&#38;K and Hickok owners to explain how to replace a #83 tube with a solid state version. This question is popular because #83 tubes are scare and expensive. Other benefits are increased reliability (no tube to wear down), less heat generated inside the tester case, and less load on the [...]]]></description>
		<wfw:commentRss>http://tubesound.com/2009/01/16/solid-state-replacement-for-83-tube/feed/</wfw:commentRss>
		<slash:comments>0</slash:comments>
		</item>
		<item>
		<title>brown-black getter flashing does not mean &#8216;Used&#8217;!</title>
		<link>http://tubesound.com/2008/09/30/brown-or-black-getter-flashing-does-not-mean-used/</link>
		<comments>http://tubesound.com/2008/09/30/brown-or-black-getter-flashing-does-not-mean-used/#comments</comments>
		<pubDate>Tue, 30 Sep 2008 15:15:36 +0000</pubDate>
		<dc:creator>Bob</dc:creator>
				<category><![CDATA[Blog]]></category>
		<category><![CDATA[Tubes]]></category>
		<category><![CDATA[discoloration]]></category>
		<category><![CDATA[flashing]]></category>
		<category><![CDATA[getter]]></category>
		<category><![CDATA[NEW]]></category>
		<category><![CDATA[NOS]]></category>
		<category><![CDATA[tube]]></category>
		<category><![CDATA[used]]></category>

		<guid isPermaLink="false">http://tubesound.com/?p=333</guid>
		<description><![CDATA[Discolored getter flashing (brown or black marks) does not mean that a tube was used. This fiction is believed by both uninformed buyers and seasoned tube jockeys. This myth seems credible because some new tubes have perfect shiny mirror getter flashing; therefore the assumption is that brown or black stains in the getter flashing must [...]]]></description>
		<wfw:commentRss>http://tubesound.com/2008/09/30/brown-or-black-getter-flashing-does-not-mean-used/feed/</wfw:commentRss>
		<slash:comments>0</slash:comments>
		</item>
		<item>
		<title>Marathon MX-280 Globe tube MESH PLATE</title>
		<link>http://tubesound.com/2008/02/26/marathon-mx-280-globe-tube-mesh-plate/</link>
		<comments>http://tubesound.com/2008/02/26/marathon-mx-280-globe-tube-mesh-plate/#comments</comments>
		<pubDate>Wed, 27 Feb 2008 03:01:19 +0000</pubDate>
		<dc:creator>Bob</dc:creator>
				<category><![CDATA[Tubes]]></category>
		<category><![CDATA[#80]]></category>
		<category><![CDATA[engraved base]]></category>
		<category><![CDATA[Globe]]></category>
		<category><![CDATA[Marathon]]></category>
		<category><![CDATA[Mesh Plate]]></category>
		<category><![CDATA[MX-280]]></category>
		<category><![CDATA[rectifier]]></category>
		<category><![CDATA[tube]]></category>

		<guid isPermaLink="false">http://tubesound.com/2008/02/26/marathon-mx-280-globe-tube-mesh-plate/</guid>
		<description><![CDATA[Here is a rare tube &#8212; a Marathon MX-280 Globe #80 rectifier tube featuring MESH PLATES construction!  Not only that, but each section tests very strong Emission, comparable to an NOS #80! In 18 years of collecting, I do not remember ever seeing another Mesh Plates #80 tube.  Look at that Glow!  You can see [...]]]></description>
		<wfw:commentRss>http://tubesound.com/2008/02/26/marathon-mx-280-globe-tube-mesh-plate/feed/</wfw:commentRss>
		<slash:comments>0</slash:comments>
		</item>
		<item>
		<title>Identifying NATIONAL UNION tubes</title>
		<link>http://tubesound.com/2007/12/16/identifying-national-union-tubes/</link>
		<comments>http://tubesound.com/2007/12/16/identifying-national-union-tubes/#comments</comments>
		<pubDate>Sun, 16 Dec 2007 17:58:55 +0000</pubDate>
		<dc:creator>Bob</dc:creator>
				<category><![CDATA[Tubes]]></category>
		<category><![CDATA[247]]></category>
		<category><![CDATA[code]]></category>
		<category><![CDATA[EIA]]></category>
		<category><![CDATA[factory]]></category>
		<category><![CDATA[manufacture]]></category>
		<category><![CDATA[NATIONAL UNION]]></category>
		<category><![CDATA[tube]]></category>

		<guid isPermaLink="false">http://tubesound.com/2007/12/16/identifying-national-union-tubes/</guid>
		<description><![CDATA[This article provides examples of NATIONAL UNION-manufactured tubes. NATIONAL UNION was another quality USA tube manufacturer with most production dating from 1930s to 1950s. Their production numbers were significantly smaller than the big name brands (RCA, Sylvania, GE). The NATIONAL UNION (EIA) code number is “247″. Here is an example: (Left = Sentinel brand 6SN7GT; [...]]]></description>
		<wfw:commentRss>http://tubesound.com/2007/12/16/identifying-national-union-tubes/feed/</wfw:commentRss>
		<slash:comments>0</slash:comments>
		</item>
		<item>
		<title>Identifying RAYTHEON tubes</title>
		<link>http://tubesound.com/2007/12/16/identifying-raytheon-tubes/</link>
		<comments>http://tubesound.com/2007/12/16/identifying-raytheon-tubes/#comments</comments>
		<pubDate>Sun, 16 Dec 2007 17:49:45 +0000</pubDate>
		<dc:creator>Bob</dc:creator>
				<category><![CDATA[Tubes]]></category>
		<category><![CDATA[280]]></category>
		<category><![CDATA[code]]></category>
		<category><![CDATA[EIA]]></category>
		<category><![CDATA[manufacture]]></category>
		<category><![CDATA[Raytheon]]></category>
		<category><![CDATA[tube]]></category>

		<guid isPermaLink="false">http://tubesound.com/2007/12/16/identifying-raytheon-tubes/</guid>
		<description><![CDATA[This post provides examples of Raytheon manufactured tubes. Raytheon was an extremely high quality USA tube manufacturer with prolific output, covering both civilian issue and a vast majority of US Military parts production. The Raytheon (EIA) code number is “280″. Here is an example: In this photo, we see three Raytheon-manufactured 6SN7GT tubes featuring Black [...]]]></description>
		<wfw:commentRss>http://tubesound.com/2007/12/16/identifying-raytheon-tubes/feed/</wfw:commentRss>
		<slash:comments>0</slash:comments>
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