How do i tell if i have a failed tube in my preamp?


Today after firing up system I noticed a distortion from all three drivers on one channel. Next I went from turn table to cd.Same thing,so I tried moving /wiggling all cables. No help or any change whatsoever.Could this be a tube going out in my BAT pre? Can I get an answer without a tear down please.I have extra tubes .6922s I believe.Thanks,R.W.
128x128rickw062
tubes are just like drugs -- reach pinnacle for short period of time than go to withdrawal symptoms :-)

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