Old tubes

[HaerdenC]

I have received from my granddad a box of radio tubes ... as he is cleaning up his house. These are really old tubes:
- can they have any vallue?
- can I use them to create some preamp or something?
- will they still be usable or do they age and die?
- is it easy to test them?

 

[JonSnell Electronic]

They can have value, depends on type numbers.
You can use most to create equipment.
They do not age with time on no use.
With a valve/tube tester they can be tested.

 

[HaerdenC]

Adzam EAF42
Adzam UF41
Adzam UY41
Adzam UL41
Adzam UAF42
Adzam DY87
Adzam PI81
Adzam PL36
Ates ecc83 12ax7
5963 usa selectron
Phillips Miniwatt pcf80 made in holland x5
EAF42 774
Phillips miniwatt uf80 made in holland x8
Phillips miniwatt PL84 x2
Phillips miniwatt PCC88
Phillips miniwatt UCC85 x2
Phillips miniwatt brand new in box no label vx9 47j
Phillips PCL82
Phillips PL83
Phillips PL36
Mub*rd UCH42 tk3 501
trona usa 5879
telefunken ech 42 made in germany
telefunken ecf 82 made in germany
telefunken ecc 82 made in germany
telefunken ef 183 made in germany
telefunken eabc 80 made in germany
telefunken ef 80 made in germany x3
telefunken ecl84 made in germany
telefunken ech 81 made in germany
telefunken el84 made in germany
telefunken el11 made in germany
telefunken el*4
telefunken small one unknown model 332 b4c*
Raytheon 0a3a made in usa 16: 280... 71-15...
unknown pcf80
on big unkown with glue form the connector solved so not fully attached anymore looking amizing doh

 

[pcan]

ecc83 (12ax7) , ecc82 , PCL82 and EL84 are audio tubes. You may build a preamp with the ECC83 or ECC82 tube - plenty of schematics are available. Other tubes useful for audio purposes are 5963 , 5879 and EL11. Most of your tubes come from B/W TVs and radios, commercial value is low.

 

[mctavish]

Not too much of value there...... Maybe the EL84 and ECC83 but otherwise.....

 

[HaerdenC]

Thnx still keeping them maybe as decoration lateron and will have a look at the usable ones

 

[PRR]

Did granddad _fix_ TV sets?

Then 90% of these tubes are high-hour tubes removed "for a reason" yet kept because they were not totally dead.

 

[Refugee1]

All the U and P numbers have various heater voltages but can be used with the correct voltage. They are made to have the heaters wired in series so that all Us take 100ma and all Ps take 300ma.

 

[HaerdenC]

Did granddad _fix_ TV sets?

Then 90% of these tubes are high-hour tubes removed "for a reason" yet kept because they were not totally dead.

Many of them are unused it was his stock ... we have a lot in common we both love diy projects and fixing old stuff

 

[Eli Duttman]

While the 2X PL84s are not EL84s with a different heater, they do seem to be OK for a low power SE stereoblock. Each channel would employ a section of the 12AX7/ECC83 as its voltage amplifier. A 36.3 V./300 mA. series heater string is a possibility.

 

[HaerdenC]

While the 2X PL84s are not EL84s with a different heater, they do seem to be OK for a low power SE stereoblock. Each channel would employ a section of the 12AX7/ECC83 as its voltage amplifier. A 36.3 V./300 mA. series heater string is a possibility.

Stupid question but can I somewhere buy a board and just pop them in ... like aliexpress or something? Or Do I really need to solder myself some board? How complex will it be ...

 

[Eli Duttman]

No PCB off the WWW, but this sort of product eases the burden of point to point wiring.

The signal circuitry is straight forward. Cap. couple a 12AX7 section voltage gain block to the power O/P tube. Use full pentode mode, with regulated screen grid (g2) B+. A (global) NFB loop connects the O/P transformer secondary to the cathode of the 'X7 voltage amplifier.

 

[AquaTarkus]

Telefunken EL84s are greatly sought after, possibly even more than Mullards and to for quite high prices on eBay.

 

[MEPER]

Is it nostalgia that some people wants the old tubes?
With todays technology it should be possible to make tubes as good as in the old days?


But I can understand that some people wants to pay 50.000 USD for a pair of 1950 300B's.......so there must be something......

 

[PRR]

....With todays technology it should be possible to make tubes as good as in the old days?......

Not really.

There is a LOT of obscure and not well understood chemistry and metallurgy in a tube. When tubes were THE electronic device, for both consumer and military electronics, they worked out supplies and processes to get very excellent results. There was volume and money in the business.

Much of that machinery and some of the material got passed-down to East Europe and China. But not the old men who could not possibly teach all the small details they had learned. By this time the big bucks were in transistors. Tubes lingered as small-market specialties, primarily guitar amplifiers. And this market is LOW-bid. The typical new-made tube may be OK, or may be worse than the cheapest old tubes.

 

[Eli Duttman]

For S&Gs, I checked EBone for the PL84=15CW5. Look here and see that both availability and cost of spares is favorable. 12AX7s are a non-issue, with several good variants in current production. Therefore, the OP can build a quite nice 5 WPC stereoblock using grandpa's gift and be reasonably certain that the amp will remain viable, for the foreseeable future. 95 or so dB. sensitive speakers are in order, but that is not especially problematic.

With g2 B+ regulated at 150 V. via a 0A2, full pentode mode PL84s will easily tolerate a minor liberty on the anode B+ limit. In any event, self (cathode) "bias eats" a few volts. With that in mind, voltage doubling the O/P of a "universal" Triad N-68X disposes of the B+ PSU, in a low cost/high performance manner.

2500 Ω O/P transformers are needed. Edcor's GXSE15-2.5K is light enough to ship long distance and is favorably priced. Sowter's SE05 is, undoubtedly, better and at 208.13 UKP each costs it. Perhaps an EU based winder can better Edcor's performance while not doing great bank balance violence.

The 300 mA./36.3 V. heater supply remains. Triad's VPS36-2200 should prove highly satisfactory and is reasonably priced.

 

[toriversen]

Many of the tubes you list is useable for audio, even if they are TV tubes, some examples:
PCF 80 can be used for a headphone amp, see, among others: https://www.circuitsonline.net/forum/view/75850/1
UCC85 is the same as ECC85, but with a 26v heater, this tube can be used in a preamp, or RIAA. Just google it, and you will find several.
PCC88 is the same as ECC88, but with a 7 volt heater.

 

[Eli Duttman]

Further review of the 15CW5 datasheet leads me to conclude that 12AX7 sections in the voltage amplifier positions will produce excessive gain. The PCC88 should be fine in the voltage amplifier role and some decent 6922s are currently being produced that will serve as replacements.

With O/P tube g2 B+ regulated at 150 V., the option of "fixed" bias should be considered. It's easy to set anode dissipation below 12 W. and ensure tube life is satisfactory.

 

[Kay Pirinha]

A 15CW5 (http://www.mif.pg.gda.pl/homepages/frank/sheets/010/p/PL84.pdf) will work happily at screen grid voltages up to 200 Vdc unregulated. Self biasing is also possible and rather common. I'd prefer it in output stages of that small power. Makes things much easier .
Best regards!

 

[Eli Duttman]

Certainly, the PL84/15CW5 will survive with 200 V. on g2. Equally certain is the fact that full pentode mode yields the most linear open loop behavior, when g2 B+ is regulated.