Mesa Boogies Blew up my HRDeluxe

Ok so it didn't blow up, but it did blow a fuse. Here's the deal, I got some Mesa 6L6GC STR-440 tubes for christmas and I put them in to replace the stocked Groove Tubes from Fender (GT6L6B). I put them in and let the amp warm up to check the bias which I had placed in the center of the pot at the time. When I turned the standby off the tubes lit up completely and after a second or two the amp lost all power and I found out the fuse was blown. I got a new fuse and tried again, this time with the amp's bias pot set as cold as possible and the same thing happened, only I shut it off before the fuse blew. I put the Groove Tubes back in and they work fine, or at least they work as well as they did before I should say. Anyways I could really use some help here guys. What could cause a problem like this? Is it just a faulty set of Tubes from Mesa or did I do something wrong? I didn't do anything differently with the Mesas than I did with the GTs so my guess is its a tube problem :confused:
Anyways, any help would be greatly appreciated. Happy Holidays from Cincinnati

Most of the time when a fuse blows it is a faulty power tube. i have bought a few sets of mesa boogie tubes where they either blew the fuse or one of the just didn't work. i only have mesa amps but i don't buy there tubes anymore. it probably had more to do with the store i bought them from not handling them carefully.

a while back I put the same mesa tubes in a HRDx and it gave the amp more balls. never harmed it though. Must have a bad tube there.

+1 on the faulty power tube diagnosis. I don't buy Mesa tubes either. I used to work for a major gear dealer. We had more Mesa amps go down than all of the other lines we carried combined. The repair shelf/area was stacked with them 24/7. A good portion of the faulty units were DOA from the factory, and aside from the Nomad series, nearly 100% of the busted ones were tube problems. We actually used to joke that "Mesa Boogie" was spanish for "crappy tubes".

Sorry to hear about your misfortune. It sucks to get a present that doesn't work right. Takes all of the excitement right out of it.

Had some bad experiences with MB tubes also. Bought four new EL84's a number of years ago. One blew after less than an hour. The others went down one by one in less than a year. Switched to JJ's and haven't looked back. However, I'm still running a couple of 12AX7's a bought at the same time. Go figure.

I've never had problems with Boogie tubes and I've been using them for at least 20 years. I have had numerous JJ's go pop though.

You got a defective tube. Shorted internally, no doubt. Return the pair under warranty.

Thanks for all the input guys. I just got back from the Bengals game but Im gonna head out to the store in a bit and exchange them. I think I may just stick with the Groove Tubes and get a new pair of those. Thanks again.

So I got the Groove Tubes put in and biased around .69-.70 and they seem to be fine, and they sound good except for the fact that the volume is now going out every fifteen minutes or so. My amp has always had a bit of a hum to it that I don't think belongs there, but it has never had problems with the volume going out like this. Does anyone know what this could be caused by?

Does anyone know what may be causing the constant hum in the amp and Volume loss?

try going here: http://www.geofex.com/ampdbug/ampdebug.htm