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Tube Troubleshooting

Hi all. I just moved across the country, and when I set up my stereo there was a loud sound of rushing air coming through my speakers. When I played music, the sound of the air was louder than the music at medium-low levels, and interfered with the sound quality regardless of how much I turned up the volume.

After some troubleshooting I determined the 6sn7 tubes in my Modwright Oppo 95 were the cause. When I swapped those two tubes out the system became dead quiet. Is this a case of tubes becoming microphonic, and if so, are tube dampers likely to help in this situation?
aggielaw
mcintech
128 posts
 
Old school method of repairing rush-afflicted and iffy tubes:

Suspend the tube upside down, and thoroughly heat up all the pins with a soldering iron (say 10 seconds per pin), if solder runs out of the end of the pin, stop as you've gotten it. (most tube pins are hollow tubes with the actual contact wire running from inside the glass envelope down into the tube, and sometimes the solder joint between pin sleeve and contact wire gets compromised).

Common repair for tubes dating back to my stint in the Navy.
aggielaw OP
267 posts
 
Abucktwoeighty: fascinating. I've enjoyed the Sophias, but now I might start looking for an alternative.

Mcintech: awesome - thank you! As the son of a former Machinest Mate, I am grateful for both your service and your passing along that handy skill!
schubert
7,386 posts
 
Everybody can't be a Fire Controlman.
abucktwoeighty's avatar
abucktwoeighty
1,079 posts
 
Mcintech, 2 years in the Navy at a NATO base repairing old tube gear that was handed down from various branches. So vintage just moving it was likely to break connections. Lots of fun with that.
One of my best friends was an MM.
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