preamp tube not working

[mesanomad100]

Hi there,so here it is
My question to you guys

I have been recording with my band in the studio I work at,All our gear has been left in Studio A,nobody else has been in all week as our stuff has been left mic'd up,well we record most fridays and last Friday everything was working swell,got some guide tracks done with my dual rec.

So,I came into the studio early Friday morning to warm up,go through my warm up regime etc etc,and get the amp sounding sweet,I plugged in done all the start up as usual,turned the amp on waited about a minute till I went to retrive my coffee and flipped the standby on,not pop or bang or anything like that went to turn it up...............Nothing not a peep,checked all cables,checked round the back of the amp,I then turned the amp master volume to aroung 3 o'clock yeah this should tear the walls down I know but only the slightest sound could be heard it didnt even sound as if there was any amplified sound at all,I routed the problem down to a preamp tune of course it would have been a preamp tune,

V1 was out,Its a 12ax7-a Russian 2 mesa tubes,but here's the problem all the chemical metallic substace fro around the tubes head(the stuff that looks like mercury)has disapeared and left a milky residue where the metal stuff used to be!!!!!!

What has happened to my preamp tube??????????????

I did replace it with another preamp tube I had from the Nomad so that is curently out of action but the dual rec is still roaring away

anybody came across this before and what causes it???

cheers guys any help would be great

Euan

 

[stokes]

Sounds like the tube cracked or somehow lost vacuum.This is why I prefer NOS,they just dont make them like they used to.

 

[mesanomad100]

is there any explanation as to why a tube has done this,it hasnt even moved so I dunno how it could have cracked,sould it have been when powered up the flow of electricity cracked it????

 

[edgarallanpoe]

is there any explanation as to why a tube has done this,it hasnt even moved so I dunno how it could have cracked,sould it have been when powered up the flow of electricity cracked it????

Could be one of about 1million reasons. Flaw in the glass, bad internal part, etc.... It happens, that is the nature of modern day tubes.

 

[Russ]

GREMLINS!!! :lol:

 

[recto-robbie]

yea it sounds like somehow your preamp tube lost its seal somehow???
I read somehwere that, that silver chemical you see on the top inside of the tube is put there to rid any remaining air left in the tube after the factory makes its final vaccume seal of the tube.
If your amp runs fine with another 12ax7 in its spot I would consider myself lucky and replace it with another,,maybe try some others,,you may find you like the sound way better with something else.

 

[treelifeUK]

I was camped by Loch Nness one night - sober! - and when I woke in the morning all my amplifiers had gone! Some monster had come in the night and chewed up all my pre-amp tubes! Does any one know of any monster repellent that may stop this happenning in the future? This also happened to me when I camped up in the top of Oz - Crocodiles?

 

[ThunderMonkey]

Any and all thermionic valve devices or tubes are just that, they are mechanical devices designed to achieve and do a specific job, over and over and over again, something is bound to give.

The phrase "They don't make 'em like they use to IS unfortunately an everyday part of our culture as it keeps people working.

There is a company that manufactured light-bulbs, there is one from the early 1900's still glowing in a New England firestation,I believe the Company has long since gone out of business. Hmmmmm.. :roll:

I like to use the analogy of any tube as metal show moshpit, just as aggressive, especially if you play more aggressively/heavy/brutal ! :twisted:

A small current of electricity (people) comes in through the pins (streets) to the filament (doors) when volume (band) is added the electrons (people) start bouncing and slamming all over the floor (grid) sometimes filling the place to capacity (plate) and heating the whole place up and getting crazy (cathode) to the point where you might get kicked out or beat up (blown tube) or not (tube good)

:wink: