Just found some old tubes

Len Amaral · Post by **Len Amaral** » 25 May 2008 6:26 am

I just found an old box of tubes that have been buried in my shed under a pile of junk. Mostly 6L6, EL-34 and EL-82 and maybe 40 12AX7. No heat in this shed so these tubes have been frozen in the winter and baked in the summer for 15 years or more.

Ya think they are still good?

David L. Donald · Post by **David L. Donald** » 25 May 2008 8:03 am

Yes, they may well be fine.

They are even doing cryogenic freezes
on some New Old Stock tubes.
Asl long as they didn't crack, they should be OK.

Well are you sure this is an
EL82 AND NOT AN EL84?

So.. these are standard types BUT
what brand names..??
That's where the rubber meets the road.

Inquiering minds want to know.

Donny Hinson · Post by **Donny Hinson** » 25 May 2008 12:24 pm

As long as the glass isn't broken, and the pins aren't too corroded, they're fine. The shelf-life of tubes is essentially "forever". I have hand-blown glass tubes made back in the '20s that still work fine! Most here aren't even old enough to remember 27's, 34's, 45's, and 80's. (They were the most popular tubes in the 1920's.)

Len Amaral · Post by **Len Amaral** » 25 May 2008 4:55 pm

Hi guys, thanks for the informatiom. Donald, they are EL-84 tubes. Time for new glasses.

David L. Donald · Post by **David L. Donald** » 25 May 2008 5:15 pm

Thought as much.

Though there IS an EL82 Pentode Philipes 1947-64

AKA 6DY5

What BRAND NAMES do you have?

Jim Sliff · Post by **Jim Sliff** » 25 May 2008 9:27 pm

The tricky part will be testing them. A Hickok 6000A or other popular tester will do a decent job on preamp tubes, but power tubes are more problematic. Tube testers only hit them with 180 volts or so on the plates, not nearly enough to know if they'll handle a guitar amp's plate voltage. You also have no way of matching them that way.

I suggest you use a tube tester to do basic screening for duds, and then do final tests and close matching using a Weber Bias Rite or equivalent tool (I us an Allesandro Bias and Matching meter).

Make sure the tube tester is calibrated before use - virtually 90% of the used ones on eBay are not calibrated, which runs about $100. Also be sure you get a transconductance (or mutual conductance) tester and not an emission tester. A cheap emission tester is useless in this type of application.

Johan Jansen · Post by **Johan Jansen** » 25 May 2008 10:40 pm

Boogie pre-amp players would love the AX7's

David L. Donald · Post by **David L. Donald** » 26 May 2008 3:03 am

Most preamps are using 12AX7s
or their euro name ECC83
or the 70-- version of better grade.
Pretty much the most common tube.

If you got some Mullard's
please send them MY way!

John Billings · Post by **John Billings** » 26 May 2008 6:01 am

Also note: The label may say a manufacturer's name, but the country of origin may tell the real story! I have many EL-84s labeled Hammond, but they also say "Made in Holland". Hammond Organ company didn't make tubes, but they used enough of them to have the actual tube manufacturer label runs of tubes as "Hammond." Look for old tubes made in England, Holland, Germany, and even France.

Jim Sliff · Post by **Jim Sliff** » 28 May 2008 9:15 am

What John said.

Most brand names of older tubes do not necessarily indicate what they actually are. I have vast collection of tubes, and there are so many variations of what look to be identical tubes it's amazing. As an example, I'm selling a pair of Sylvania El34/6CA7's on eBay (no, I'm not shilling the auction!) and there are some technical details I added to the description that seem silly, but they mean a lot to collectors and serious players - the shapes and number of holes on the plates, welding marks, even whether they have a tiny hole in the end of the plastic centering pin - all those things identify which of 4-or-5 actual *manufacturers* made the "Sylvania" tube and what it will sound like.

A stash like you found needs to be gone through first with a decent tube tester to weed out the duds - then preamp tubes tested in an actual amp for gain and microphonics, and power tubes matched using a Weber Bias Rite, Allesandro Bias and Matching Meter or similar. It might be worth the $100-125 for one of those tools to match the tubes (the EL84's are a little tougher to match - I genrally just test them and then give them the "ear matching" test combining pairs in an amp that uses them) - a Deluxe Reverb is a good amp for checking both 6V6 and 6L6 tubes - most 6L^ amps will kill 6V6's, and 6V6-powered ones not supply enough voltage to 6L6's...but a DR is right on the edge and a good test bed amp.

I say all this because you can almost certainly sell pairs or quads of US and Western European power tubes for some pretty decent $$, and some preamp tubes go for $20-50 each. But you have to test them to know is they are good enough to sell or use. DO NOT stick them in an amp untested - that's good way to blow a cap...or even an output transformer!

Len Amaral · Post by **Len Amaral** » 28 May 2008 12:27 pm

Hey guys, thanks for the feedback. I have to go through theses tubes and clean them up. The preamp tubes are mostly 12ax7 with a few 12at7. I guess the best way test these tubes without a testing device is to fire them up and see what happens.

Andy Zynda · Post by **Andy Zynda** » 28 May 2008 12:35 pm

When you clean them, dont use glass cleaner or any solvents. Just a very minimal amount of water on a damp cloth. The glass cleaner may remove any inked lettering. (spoken from experience

)
Even water can dissolve some lettering.
Congrats a bunch on the tube motherlode!
-andy-

T. C. Furlong · Post by **T. C. Furlong** » 1 Jun 2008 1:55 pm

At a flea market, I just picked up a number of new looking tubes (12AX7s and 6V6s)that are labeled Bell & Howell made in Great Britian. Does anyone know who may have made these?
TC

John Billings · Post by **John Billings** » 1 Jun 2008 1:56 pm

Could be Mullard's. They'll be good fer shure!

Dan Tyack · Post by **Dan Tyack** » 2 Jun 2008 5:46 am

If you have any Tung-Sol 5881 tubes (6L6 type with brown base) I'll take them off your hands!

Because most of the amps I use are class A single ended (don't need a matched pair) I usually just stick them in the amp and see how they sound. One of my favorites is an old Tung Sol 5881 which is just about worn out. It doesn't put out much power, but man does it sound good!

John Billings · Post by **John Billings** » 2 Jun 2008 5:56 am

Dan, those are great tubes! I use them in my Tweed amps. I work for a water company, and I used to do everything, including reading the meters. I went into this old guy's house, and saw a few Hammonds and a lot of electronic equipment.
We got to talkin' and I told him I liked tube amps. He showed me into his supply storeroom. One whole wall was stacked with boxes of tubes. NOS, pulls, everything. When I went back to read his meter at Christmastime, he gave me a dozen NOS Tungsol 5881s! I've gotten hundreds of tubes from him. Speakers too.

Len Amaral · Post by **Len Amaral** » 2 Jun 2008 6:01 am

Most of the tubes (50)were 12AX7, a few 12AT7 a one 12AU7 with a quartet of 6L6, a quartet of EL-82 and a few EL-34. I'll clean them up and and hold onto them for future use.

Dan Tyack · Post by **Dan Tyack** » 2 Jun 2008 6:13 am

John,

This older guy at an electronic store told me that the Tung-Sol 5881 was designed for use in the gun turret of a B-36 bomber...

(tube trivia)

Jim Sliff · Post by **Jim Sliff** » 2 Jun 2008 6:43 am

I guess the best way test these tubes without a testing device is to fire them up and see what happens.

That's a really bad idea. At bare minimum spend $40 on an emission tester to at least check them for shorts and whether they are alive or dead. Inserting a shorted tube, the "see what happens" part will probably be quite expensive.

Ditto on the Tung-Sol 5881's. I have a good stash of 'em. Just don't put them in a Twin or other high plate voltage amp - they're not designed for 460V on the plates and can cook off rather quickly.

The Steel Guitar Forum

Just found some old tubes

Just found some old tubes

Cleaners!