Damsel in Distress with Jadis DPL

Caught the tube rolling bug and acquired a pair of 12AU7 "supposedly" NOS Phillip Mullard collaboration tube along with a RCA 12AX7 for my Jadis DPL preamp. Experienced a loud crack from left channel through my loud speaker. Left speaker went completely dead. Removed all 3 tubes and re-installed original compliment. Everything is back to normal. Or so it seems. What happened? Did I do any damage? Any comments welcome ~ Deb
Is the sound back to normal Deb? If so then it would seem like you simply had a tube go bad...these things happen, and you should have no more worries. If the left speaker is still dead, perhaps the tube took a driver or two with in with some DC leakage.

FWIW, I've found that some equipment, like my BAT VK-75SE amp, are not too friendly to NOS tubes. I spent some big $$$ on a few NOS Sylvania 6SN7's, the right channel (3 per side) crapped out after about a week. The BAT preffered the more durable Russian tubes....lesson learned.

I agree that it was probably a tube failure. I've used the same set of Telefunkens in my JPS2 for 13 years and never had a failure.
As long as everything is still in balance between your channels, the bad tube didn't take anything with it. New production tubes go bad just as often as NOS tubes, and some defects are hard to find until the tube has full operational voltage applied to it. Always purchase tubes from reputable dealers(with stringent test procedures) to avoid the occasional high-dollar, NOS counterfeit(from China, etc.).
I should have mentioned: Don't let this experience dissuade you from pursuing NOS replacements for your unit. Their sonic benefits over what's being manufactured today will make your efforts well worth it.
Some NOS tubes may have a lower voltage rating. Take 6SN7 as an example. The NOS 6SN7GT has a max plate voltage of 300V. The newer 6SN7GTA/B have a higher voltage at 450V.
Vett- Look at this data sheet for the old Sylvania 6SN7GTA (http://home.comcast.net/~tubes/Syl55/Get_Page.html?175). It's plate voltage is also 450V. The tube you mention is a 6SN7GTA/B- same designation with a "b" added. That's what the different suffixes refer to on tubes: Slight variations in the basic design. The plate voltages on NOS 6sn7 tubes can vary from 275V to 450V, depending on the design, and the typical contemporary 6SN7 circuit delivers 250V. MS N's unit doesn't take 6SN7s though, and miniature nine-pins don't vary much at all in plate voltage specs(new or old)within the same family. Here's a site that lists the various plate voltages of the most popular NOS tubes within the 6SN7 family (just FYI): (http://home.att.net/~chimeraone/6sn7sound.html)
Damsel...Im not sure what 6sn7 tubes have to do with your Jadis pre(focus guys !)I strongly suggest Mullard 7025 in place of the 12ax7(late 1950s/early 1960s issue)..Higher gain,less strain but still warmth..IMO,Forget that RCA 5751 someone suggested,will take the Jadis to a lower performance level .. No point in doing that..Install Mullard 12au7s (again from the late 50s or 60s,go to ebay and buy from solid seller only,make sure to check their output before installing)..If you want a more sterile less Jadis sound try the Tele tubes...oh did you see the knobs on sale for 100 each,a deal these days..
Mr M- If you'd bother to read the posts: I was trying to teach Vett(or anyone else that might be interested in NOS tubes) a little something about 6SN7s(a subject HE brought up). Or- isn't that allowed on your site? OH! What exactly do "knobs" have to do with Damsel's problem BTW? Focus Mr M, focus!
my mistake..sorry to step on your educational toes...go ahead with your leason....BTW , she has asked about getting knobs in a previous post..keep up now