Home » Audio » Thermionic Emissions » please help?
please help? [message #9993] Wed, 12 September 2007 15:46 Go to next message
Gilipsie is currently offline  Gilipsie
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Registered: May 2009
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My friend just bought a quad of Alpha branded E84L tubes to test. They seem fine tested as a 6BQ5 but gave him a loud hum in his guitar amp as soon as they came up. Any idea why?

Re: please help? [message #9994 is a reply to message #9993] Thu, 13 September 2007 12:21 Go to previous messageGo to next message
metasonix is currently offline  metasonix
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Registered: May 2009
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usually this is due to a bad tube dragging down the plate supply. I never heard of "Alpha". It is probably a junk brand from the bad old days (before the industry collapsed in the late 1980s).

JJ EL84s seem to be the best ones being made today. Unfortunately good NOS EL84s are almost impossible to find, so you'll have to use current production.

Re: please help? [message #9996 is a reply to message #9993] Sat, 15 September 2007 18:29 Go to previous messageGo to next message
granch is currently offline  granch
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Registered: May 2009
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I would wonder why did your friend buy the new tubes? Maybe his amp "went west" and blew the prior set. Is he sure the problem is the new tubes or the old amplifier?
-Dick

Re: please help? [message #9999 is a reply to message #9994] Tue, 02 October 2007 10:21 Go to previous message
Crystal is currently offline  Crystal
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Registered: May 2009
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Alpahs aren't any good at all. So I think that may be one of the reasons why your tube might be bad. My brother use to have one. He bought it from the flea market and every single time he attempted to use it, he got the same results which was that great old humming.

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