Heavy duty 12AT7 for a reverb driver

[skankdelvar]

Ghastly to bring it up on a bass forum, I know. But I keep blowing up 12AT7's in the reverb socket of an old Silverface Pro Reverb (Ed Jahns UL transformer / MV type).

Before I hoick the offending Fender off to a solder-covered gnome bloody miles away, does anyone have any recommendations for a seriously heavy duty 12AT7? That way, if it blows, I'll know it's probably a fault rather than crappy tubes.

Thanks in anticipation.

Edited July 25, 2011 by skankdelvar

[brensabre79]

If there is a fault it could blow even the most hardy tube - check out watford valves though they give pretty good advice on their site as to how fragile or not the different tubes are. instinct says get something russian

[skankdelvar]

Thank you brensabre.

Any more for anymore?

[Mr. Foxen]

Know how to work a multimeter?

[url="http://www.hobby-hour.com/electronics/resistorcalculator.php"]Usning this handy resistor calculator[/url] you can test the resistors relating to that valve are in spec, in case they are the issue.

[Subthumper]

If it keeps blowing the valves then I'd recomend getting the reverb transformer checked out along with the reverb tank. There could be a breakdown in the windings causing a short that is too much of a load on the driver valve. The circuit is basically a single ended amp that drives the reverb springline and will have the same effect on the valve as a bad speaker load on an amp. Best get these checked by a tech than keep throwing valves at it.
Good luck
Cheers Just