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Post by carrjimi on Feb 24, 2013 20:50:17 GMT -7
JAN Phillips NOS about 20 Hours on them. When I touch them to stop the rattling they howl like crazy.
They still sound fine otherwise. The howling/screaming thing was really weird. They also glow blue purple. Are they on their way out?
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Post by digiTED aka 'Ted' on Feb 24, 2013 20:54:42 GMT -7
The prognosis is grim.
How hot is your bias?
Do you have an alternate 'known good' pair to pop in just to check?
Has your amp or the tubes themselves been jostled around to your knowledge?
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Post by carrjimi on Feb 24, 2013 21:09:00 GMT -7
I've got them biased at 29ma. I'm usually pretty careful with the amp. Hate to have to buy a new pair so soon they were pretty expensive!
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Post by digiTED aka 'Ted' on Feb 24, 2013 22:43:08 GMT -7
I hear you, man. Bummer on the spendy glass. Do you have a cathode bias 6V6 x 2 amp around to test those tubes to see if they behave somewhere else?
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Post by carrjimi on Feb 25, 2013 5:42:38 GMT -7
unfortunately no. I just ordered a new set. $80 ouch!
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Post by "Z" Steve on Feb 25, 2013 17:44:13 GMT -7
I went through the same thing about a year ago. The vendor was great about letting me return them and sending me a new set of the same ones but they did the same thing. The consensus here was that the reissue Tungsols are a great buy for the price and the tone is great (which they are) so I went ahead and bought those instead and used the NOS for a friends old Champ. It bummed me out because the reviews were great, but just as with NOS rectifiers (for me anyway) it seems the larger the glass the more likely you are to have rattling or other issues.
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Post by myles on Mar 1, 2013 14:14:03 GMT -7
Physical microphonics has nothing to do with bias. You have a bad set of tubes. Replace them. Perhaps they incurred shipping damage or handling damage.
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