|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
108.43.129.62
My tube preamp started acting up in the left channel. I tested the tubes (CJ ART, 5 6922's per channel) and one of the 6922's showed grid emission "reject" immediately on the meter. Replaced that tube and all is well.
Over the years I've had a few tubes short on me but never had a grid emission failure. I'd like to know what it means if someone could explain it in not too technical of terms. Thanks.
Follow Ups:
Three possibilities, all giving the same symptoms:
1) Gas can result in current flow, upsetting grid bias
2) Conductive deposits inside (on the mica insulators mostly) or outside.
3) Actual grid emission - the grid is close to the cathode and gets heated - and some cathode material can get transferred onto it. If it emits electrons, it's going positive.
A tube tester can only measure the effect - can't tell you the cause. Some say "Grid Emission", some say "Gas", some just "leakage".
It's the result of a gassy tube. Positive ions are created by current through the tube. The ions are than attracted to the negatively-charged grid, creating grid current. Not sure how well simple testers differentiate between this and a shorted grid.
--------------------------
Buy Chinese. Bury freedom.
h
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: