7027a testing

brucedc · 8th August 2011, 02:49 PM

Just arrived here and left a short introduction. Looks like a great forum.

This is my question: When I'm out checking on possible tube buys I take my little EMC 213 tester with me for quick quality and short checks before buying. Problem I have is there are no settings listed for 7027/7027a tubes. They will not test properly on 6L6 setting, I assume because of the 2 extra pins. Can someone tell me what those settings would be or where I could find them? I'm having no luck at all..thanks..bruce

danFrank · 8th August 2011, 08:23 PM

7027 is electrically the same thing as a 6L6 but has higher voltage / dissipation ratings. You are right about the two pins, that is probably giving you troubles on testing. They would be pins one (1) and six (6). If you have a tube tester that you can select what the different pins of the tube under test see, make sure pins 1 and 6 are NOT connected to anything. Then it should test like any other glass 6L6. The other thing you can do is cut pins 1 and 6 off of the 7027 and then it will test correctly on the 6L6 setting. This will devalue the tube though.
Daniel

SY · 8th August 2011, 09:06 PM

Dan, specifically, it's a slightly re-pinned version of 6L6GC. One can rig up an adapter socket to use it in 6L6 tests or amplifiers.

brucedc · 9th August 2011, 12:05 PM

SY..could you tell me how to do that?

SY · 9th August 2011, 12:42 PM

Sure. Get yourself an octal plug and an octal socket. Using a relatively stiff wire, you can connect the two, with the socket floating about 1 cm or so above the plug. Care must be taken when plugging and unplugging! If you're a real studboy, you'll find some high voltage potting material and make it into a monolithic assembly which will be considerably less fragile.

Tom Bavis · 9th August 2011, 01:23 PM

In most cases, 7027 and 6L6GC are interchangeable. Amps with 7027 seldom used pins 1 and 6 (but check!). 6L6 amps may have used pins 1 and 6 as tie points - move these wires to a new terminal and either will work. I don't have an EMC tester any more, but I believe it has a switch corresponding to each pin. Set for 6L6, set switch #6 to the same position as #5, set switch #1 to the same position as #4, and test. Pins 1 and 6 may test "short" - ignore.

brucedc · 14th August 2011, 12:52 PM

Thanks Tom that worked perfectly!

8th August 2011, 09:06 PM	#3
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	Dan, specifically, it's a slightly re-pinned version of 6L6GC. One can rig up an adapter socket to use it in 6L6 tests or amplifiers. __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

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8th August 2011, 02:49 PM	#1
brucedc diyAudio Member Join Date: Aug 2011	7027a testing Just arrived here and left a short introduction. Looks like a great forum. This is my question: When I'm out checking on possible tube buys I take my little EMC 213 tester with me for quick quality and short checks before buying. Problem I have is there are no settings listed for 7027/7027a tubes. They will not test properly on 6L6 setting, I assume because of the 2 extra pins. Can someone tell me what those settings would be or where I could find them? I'm having no luck at all..thanks..bruce

8th August 2011, 08:23 PM	#2
danFrank diyAudio Member Join Date: May 2005 Location: California	7027 is electrically the same thing as a 6L6 but has higher voltage / dissipation ratings. You are right about the two pins, that is probably giving you troubles on testing. They would be pins one (1) and six (6). If you have a tube tester that you can select what the different pins of the tube under test see, make sure pins 1 and 6 are NOT connected to anything. Then it should test like any other glass 6L6. The other thing you can do is cut pins 1 and 6 off of the 7027 and then it will test correctly on the 6L6 setting. This will devalue the tube though. Daniel

9th August 2011, 12:05 PM	#4
brucedc diyAudio Member Join Date: Aug 2011	SY..could you tell me how to do that?

9th August 2011, 12:42 PM	#5
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	Sure. Get yourself an octal plug and an octal socket. Using a relatively stiff wire, you can connect the two, with the socket floating about 1 cm or so above the plug. Care must be taken when plugging and unplugging! If you're a real studboy, you'll find some high voltage potting material and make it into a monolithic assembly which will be considerably less fragile. __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

9th August 2011, 01:23 PM	#6
Tom Bavis diyAudio Member Join Date: Jun 2002 Location: Macedon NY	In most cases, 7027 and 6L6GC are interchangeable. Amps with 7027 seldom used pins 1 and 6 (but check!). 6L6 amps may have used pins 1 and 6 as tie points - move these wires to a new terminal and either will work. I don't have an EMC tester any more, but I believe it has a switch corresponding to each pin. Set for 6L6, set switch #6 to the same position as #5, set switch #1 to the same position as #4, and test. Pins 1 and 6 may test "short" - ignore.

14th August 2011, 12:52 PM	#7
brucedc diyAudio Member Join Date: Aug 2011	Thanks Tom that worked perfectly!

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