Help Identifying Useful Tubes?

[Theashe]

Hey all,

I've been a lurker here for a few months now, while I've been putting together the know-how to design and build my first tube amplifier. I recently came across a big box of old tubes, and since I'm only familiar with a few various types of tubes common in guitar amplifier circuits, I was wondering if anyone here could help me identify the historic and/or current uses of some of the tubes that I've found (to give me ideas for projects down the road, or tell me whether I should sell some of the tubes that I'll never use).

Here's a list of the tubes, starting with small bottles:

1S2A
1X2B
2BN4A
2FS5
35C3
35C5A
3AL5
3AU6
3BU8A
3BZ6
3CB6
3GK5
4EH7
4ES8
50B5
5642
5879
5T8
5U8
6399
6AK5
6AQ5A
6AT6 (already familiar)
6AU8
6AU8A
6AV6 (already familiar)
6BA8A
6BC8
6BH8
6BL8
6BR8A
6BU8A
6BW4
6CB6
6CL8A
6CS6
6CU5
6CW5
6CY5
6CY7
6DE6
6DE7
6EJ7
6GH8A
6HG5
6JU8A
6JV8
6S4A
7ES8
8DX8
8LT8
9A8
12AQ5 (already familiar)
12AT6A (already familiar)
12AU6 (already familiar)
12AU6A (already familiar)
12CU5L8
12CW4
12DT5
12FX5
12HG7
12X4
13CW4
17Z3

And large bottles:

6AV5GA
6CD6GA
6DQ6B
6GE5
6HV5A
6JM6A
6JN6
6KM6
6KN6
12GE5
17DQ6B
21GY5
21JZ6
21LU8
22JF6
22JU6
24LQ6
25CD6GB
29KQ6
33GT7
33GY7A
36KD6
38HE7
38HK7
40KD6


I just want to say thank you for all of the indirect help that I've gotten from members here getting started as a DIY hobbyist. None of these are tubes that I plan to use in my first tube amp build (I've got a few 12AX7s and TAD 6L6GC's lying around for that), but hopefully I can find some use for them in other projects down the road (maybe a hi-fi stereo amplifier?).

Best,

Dave

[Leo_Gnardo]

6AQ5 is a dandy little power tube, works similar to an EL84. Nice for making "little screamers."

Can't say I see much useful on the rest of the list, except the ones you're already familiar with.

[tubeswell]

Best datasheet site is http://frank.pocnet.net

http://www.r-type.org is useful for a potted history of certain types

[gui_tarzan]

Most of those are radio/TV tubes and aren't good for much. I have a couple of big boxes of them too. You could always solder them to a pair of low volt wires and have an interesting Christmas tree this year.

[Theashe]

Just for interest's sake, I found a thread on another forum about using horizontal TV tubes in audio amplifiers. There's some neat talk surrounding 6AV5, 6CD6GA, and 6JN6 tubes. I'll have to look into it more in the morning.

http://www.diyaudio.com/forums/tubes-va ... ier-2.html

You could always solder them to a pair of low volt wires and have an interesting Christmas tree this year.

They're glorified lightbulbs anyway.

[Leo_Gnardo]

Just for interest's sake, I found a thread on another forum about using horizontal TV tubes in audio amplifiers. There's some neat talk surrounding 6AV5, 6CD6GA, and 6JN6 tubes. I'll have to look into it more in the morning.

http://www.diyaudio.com/forums/tubes-va ... ier-2.html

You could always solder them to a pair of low volt wires and have an interesting Christmas tree this year.

They're glorified lightbulbs anyway.

Yes, some folks like to make amps with "sweep tubes." Most are kitted together by hobbyists for a lark. Notice sellers like Antique offer short or no warrantee on them. OTOH I think the venerable McIntosh 3500 used a rack of 8 tubes, 6LQ6 if I'm not mistook, usually used as "sweeps" to good effect, 350 watts mono, with a wonderful tone.

Glorified lightbulbs, consider the Russian term on their tube boxes: Elektronika Lampa, that about says it all. Ah but they're so much fun.

[shoggoth]

Most of those are radio/TV tubes and aren't good for much. I have a couple of big boxes of them too. You could always solder them to a pair of low volt wires and have an interesting Christmas tree this year.

They can all be used in guitar amps in some way, shape or form - but will require a ton of work, as probably every aspect of the design is going to be novel.

Personally I love oddball tubes.

[Phil_S]

From what I see 5879 is a pentode/triode. The triode seems to be similar to a 12AU7. The pentode might be used for an input tube, similar to an EF86.

6AK5 might be used as in input pentode.

6AQ5 or 6AQ5A can be used like a 6V6, but not more than 300V. Great tube.

6AU8 pentode/triode. Might be OK to use the triode for a gain stage and the pentode for output.

6AV5GA possible output pentode (OK, beam tetrode.)

If this sort of thing floats your boat, have at it!

[Bob S]

Yup - I've seen 5879's get some loving on TAG.
ToneMerc or 10thTx used them on some designs as an alternate pentode.
I bought a few to try but haven't gotten around to it yet.
A lot of us must have mystery boxes of tubes - I delved into mine a while back when I was restoring an old Grundig radio. Didn't find what I was looking for but I did find a Mullard short plate ecc83 & an ef86. Pleased I didn't drag the box out to the road when I was shop cleaning.

[tubeswell]

the 5879 is a small-signal pentode only. I have used 5879s in a modified version of Merlin's small signal pentode morph control. In the following schematic the 12AU7 triode forms a CF buffer that drives the morph control in 'triode mode', as well as buffering the following load.

[Stevem]

Those 6GH8A tubes can be used with a common adapter socket to replace a 7199 in a lot of vintage amps that use it a the driver and PI!

[dorrisant]

As mentioned above the 5879 is a wonderful little Pentode!! Look at this link:

http://el34world.com/Forum/index.php?topic=5901.0

A lot of the guys on there are also members here.

Most of these guys agreed that the 5879 was magic. They also tried a bunch of different (some oddball) power tubes... Maybe you could find a good starting point there. I built a sweet "beaks and feet" single ended amp by studying that thread.

Oh yeah, welcome to the forum. Glad you are joining the conversation!

Tony

[dorrisant]

As mentioned above the 5879 is a wonderful little Pentode!! Look at this link

http://el34world.com/Forum/index.php?topic=5901.0

Most of these guys agreed that thaw 5879 was magic. They also tried a bunch of different (some oddball) power tubes... Maybe you could find a good starting point there. I built a sweet "beaks and feet" single ended amp by studying that thread.

Oh yeah, welcome to the forum. Glad you are joining the conversation!

Tony