Valve Shelf Life...

[Lavox]

Sup guys,

Very quick question for you here. I work in a guitar store and was rooting around the old filing drawers in the back office and found some old Mullard EL84s. They're not the reissues and have the original boxes (which are covered in dust). They were well wrapped up and sparkle as clean as any 'new' valve does. Does anyone know what a valve's 'shelf life' is? How long can they be stored for not being used and still give full performance when they finally get installed?

Also, if they're still good, can I put one into my class 5? Doesn't need to be biased does it?

Thanks in advance folks.
Lavox

[surfnorthwest]

If they are truly old Mullards that's is a nice find. The way those tubes were constructed back then the shelf life would be many years. I is not unheard of to find NOS tubes from the 50 and 60s that are new. Unless the tube was damaged or leaked they are as good as new.

Have the tubes tested by someone that has a good tube tester if you want to know for sure. There is a good market for Mullards that test high.

[Lavox]

Unless the tube was damaged or leaked they are as good as new.

Really? There's 6 in particular that had never been opened until I took them out. All look absolutely fine. There are around 12 altogether I think (I'm back home now so this next bit might be bullshit!) and they all have the Mullard logo that looks like a diamond with the words MULLARD written in capitals through the middle. I'll try to find a pic.

There is a good market for Mullards that test high.

My boss said that I can have two of them and he's keeping the rest so looks like when I pulled them out of the back room it rang a bell! He had a look as if to say 'I haven't thought about those for 40 years!!!' He's taken them all home and is going to test them all tonight. How much do they go for now anyway? Maybe I shouldn't be pissing around putting a NOS tube in a class 5 if they're worth anything.


Thanks for the reply man, I'll try to find a pic of that old logo.

-- Fri May 07, 2010 5:41 pm --

Here's a pic from a tube site. They're exactly the same as the middle one I think. There were also 3 EL34s there too but they weren't in boxes or anything, just rolling around the back of the drawer.

[surfnorthwest]

Yep those all look to be all old EL84 Mullards. The factory made tube under a few different names also. If they all test well you have some money there. $75+ for a new Mullard is the going price.

I would definitly plug one into the C5 and see how it sounds. These old Mullards will also last longer than modern production tubes

[Lavox]

Jeez! $75 each for a good 'un? That should keep our beer fund going for a while back at the shop! Will get bring one home tomorrow and give it a shot in the Class 5.

Do you have any recommendations for a complementing pair of ECC83s for it?

[surfnorthwest]

I am not that familier with the C5 but I would think the stock tube would be your best bet. You should hear a difference with that Mullard in there though.

[LivewireBlanco]

I think those tubes about have a 5 year shelf life. They are no good any more and you should give them to me for proper disposal...

Awesome find!

[Lavox]

Bwahahahaha. My face actually dropped when I read the first words of your sentence! I'm going to keep looking around that old room when I get back to work tomorrow. Who knows what other little treasures are hiding in those drawers.

If I happen to find an old '59 Les Paul kicking around or maybe a Tweed '57 Champ then I think this is the last you'll hear of me! If I don't, then I'll update you all in the morning

Thanks for the input gents

[Ron Vogel]

They pretty much last forever. I deal with a lot of old tube stuff...40's, 50's, 60's...most of the stuff I get has original tubes in it...still working.

I have a mid '60s JAN EL84, and late '50s RCA 12ax7's in my Class 5...it's a whole different (and better) amp.

I keep trying to like new production tubes...just haven't run across any near as good as 50s and 60s production.

I also have a few "new" tubes from that era...just have to go to the right estate sales:


As far as EL84's go, the Mullard's are good...but the Amperex Bugle boy (made in Holland) are the best. Once the new baffle is finished for my Class 5, the JAN is coming out for the Amperex.

[MartyStrat54]

Just a quick note on Philips made tubes. Philips was the largest tube manufacturer and it was very common for various Philips brands to make tubes for each other. An example would be Amperex tubes that are actually Mullards. Valvo's and MiniWatts are other tubes that can be made at other Philips plants. The best way to tell is the guts of the tube and the codes that are etched on the lower side of the tube.