ID these valves

DiscoStu

Whilst clearing out my dad's old shed recently (he passed away 2005) I found these old valves.
Don't know what they are, can some of you valve spods ID them?
Are they any use for guitar amps and how would I test them to know if they're working?

Over to you!

https://i.imgur.com/ekgcKCs.jpg
https://i.imgur.com/MLzBsbX.jpg
https://i.imgur.com/EB5XU5c.jpg
https://i.imgur.com/oHAkjI9.jpg
https://i.imgur.com/M1yvZ2x.jpg

ecc83

From the top,

6BR7 low noise pentode, similar to, might be pin for pin to an EF86. Prized by the  audiophool brigade I shouldn't wonder?

UY85 . SIngle diode power rectifier for series heated applications. Pretty useless for guitar amps but the vintage radio guys might give y ou a few quid for it.

12AX7 need I say more?

EL84? But might be a UL84, series heaters again and not useful.

Octal magic eye tuning indicator?

Testing? You either need a universal valve tester or the bit of kit they fit!

Dave.

DiscoStu

Cheers Dave. Some were loose in a box and some others came out of a home made record player! I recall dad getting an electronics magazine back in the 70s.
There is blackening on the glass of some of them, does that mean they're blown? I really don't know anything about valves.

Maynehead

DiscoStu said:

Cheers Dave. Some were loose in a box and some others came out of a home made record player! I recall dad getting an electronics magazine back in the 70s.
There is blackening on the glass of some of them, does that mean they're blown? I really don't know anything about valves.

The “blackening” is the getter flash, and is actually a sign of a healthy valve. It’s only a problem if they turn white, which means the valve has lost its vacuum.

That Brimar 12ax7 is one of the more desireable preamp valves for guitar amps so I’m sure someone here will snap it up.

DiscoStu

Maynehead said:

That Brimar 12ax7 is one of the more desireable preamp valves for guitar amps so I’m sure someone here will snap it up.

Oo! Is it indeed? 

Funkfingers

That assortment could be the mortal remains of an old television or radiogram. (Ask your grandfather!)

tekbow

That's an old old Brimar too. Long plate by the looks of it.

Any other numbers on it than the 320? If there's something with a letter, that'll be a date code.

Nerd moment. Who knows why Brimar's have the 12ax7 label whilst other European Manufacturers called them ECC83's?

olafgarten

tekbow said:

That's an old old Brimar too. Long plate by the looks of it.

Any other numbers on it than the 320? If there's something with a letter, that'll be a date code.

Nerd moment. Who knows why Brimar's have the 12ax7 label whilst other European Manufacturers called them ECC83's?

This might be wrong, but I think it's because Brimar were created to replicate American valves.

tekbow

olafgarten said:

tekbow said:

That's an old old Brimar too. Long plate by the looks of it.

Any other numbers on it than the 320? If there's something with a letter, that'll be a date code.

Nerd moment. Who knows why Brimar's have the 12ax7 label whilst other European Manufacturers called them ECC83's?

This might be wrong, but I think it's because Brimar were created to replicate American valves.

Correct! AFAIK anyway.

BRItsh Made American Radio valves. They made american pattern valves in the UK as they were originally owned by Standard Telephone and Cable (STC).

I've got some 60's Brimar's. By that stage they were mostly making stuff for the MOD, so weren't a lot different from Mullard CV tubes as they were using the same specifications.

Maynehead

tekbow said:

That's an old old Brimar too. Long plate by the looks of it.

Any other numbers on it than the 320? If there's something with a letter, that'll be a date code.

Nerd moment. Who knows why Brimar's have the 12ax7 label whilst other European Manufacturers called them ECC83's?

Because they were designated for the American market?

I’m guessing this one is mid 50’s.

tekbow

@Maynehead I'd say that's about right. They seem to have switched to shorter plates around the same period Mullard and everyone else did.

DiscoStu

Well you've lost me!
Other than the 320 on the front of the Brimar 12AX7, there is 3A6/573 on the rear.

tekbow

3 week of January 1956 or 1966. And because that looks like a long plate, I'll say 56.

The second set of 3 after the slash are an internal code (engineering code?) For that version of the 12ax7.

http://www.g8hqp.me.uk/audio/brimarcodes.html

There's a 571 (12au7) on that list, then later a 1571, 1572 and 1573, which are a later 12au7, a 12ax7 CV492 spec 14mm plate and a 12ax7.

So I'll bet the 1 is an engineering change code associated with shorter plates.

So @Maynehead was bang on the money with mid 50's.

DiscoStu

Nice one @tekbow . So that's good, right?

tekbow

If the valve tests good, then it's good from a certain point of view.

NOS long plates of certain brands go for silly money. Mullard, Telefunken, Raytheon black plates etc. Brimar don't seem to have the recognition that Mullard do, at least yet, but I prefer them (and a couple of other tubes) to Mullard.

There's a lot of tone mojo talk about long plates, but the there's a reason everyone switched to short plates. Less microphonics, which I guess in the applications they were designed for (not guitar amps) meant better signal to noise ratios? Or something.

It would generally be said that long plates perform better in heads than combos from a microphonics point of view. At least that's the prevailing wisdom. Plausible to me anyway.

tekbow

But yes, if tests as new, or good, should be worth a few quid.

Maynehead

DiscoStu said:

Nice one @tekbow . So that's good, right?

Only if it works 

If it was tested with a valve testing kit and found to be strong and balanced however, it’ll fetch a lot more, but just knowing it works would be a good start.

DiscoStu

tekbow said:

But yes, if tests as new, or good, should be worth a few quid.

Maynehead said:

DiscoStu said:

Nice one @tekbow . So that's good, right?

Only if it works 

If it was tested with a valve testing kit and found to be strong and balanced however, it’ll fetch a lot more, but just knowing it works would be a good start.

So how do I do that cost effectively?

DiscoStu

I have a Blackstar HT60 Stage. It has 2xECC83 and 2xEL34.
I'm showing my naivety here but could I put the 12AX7 in my amp to see if it works or would I be risking my amp?

tekbow

If there's a good amp tech you're friendly with in your area they might have an old school valve tester they'd check it on for you for the fun of looking at an old tube.

I can't stop my tech. Every time I take an amp to him, he has all the tubes out, tests them on an AVO tester. I think he enjoys it.

Maynehead

DiscoStu said:

I have a Blackstar HT60 Stage. It has 2xECC83 and 2xEL34.
I'm showing my naivety here but could I put the 12AX7 in my amp to see if it works or would I be risking my amp?

Yep, just stick it in there and see if you notice any difference... More/less gain? Brighter/darker/clearer? Smoke/fire? All useful information 

Edit: I was joking about the last part, it should be safe.