My old faithful Laney VC30 has been letting me down in recent times...

In the 4-5 years I've had it, I've changed the pre-amp tubes around once a year and never had any issues. However, since I changed them about 2-3 months ago the one in slot 2 (which controls the drive channel) has let me down & had to be replaced 3 times. As it died again during band practice this weekend, I figured it was time to see if anyone has any ideas what could be going on.

I've been using JJ 12ax7 tubes, nothing out of the ordinary & no different to what's been in there the whole time I've had the amp.

Have I just got unlucky with buying a bad batch of tubes, or could there be something more seriously wrong with my amp that needs looking at by a technician?
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