NOS Telefunken EF12 steel tubes found!

[mateus]

UPDATED TABLE

MODEL	QTD	SOLD	FREQ	BASE	EQUIVALENT	TOPOLOGY	BRAND
12BY7A	6		TV	B9A	EL180/12BV7/12DQ7	TETRODO	(6)RCA
6AL5	15		RF	B7G		Two separate signal diodes	(10)RCA (5)РАДИО AАMПA
6BQ7A	8		RF	B9A	Próxima da 6922, conferir diferenças.	DUPLO TRIODO	(8)TOSHIBA
6CA7	77		AF	IO	EL34/KT77	PENTODO	(77)SAMSUNG-NEC
6SA7	5		RF	IO	6A7	HEPTODO	(4)РАДИО AАMПA (1)RAYTRONIC
6SK7	3		RF	IO	Rádio	PENTODO	(3)RAYTRONIC
6SN7	14		AF	IO	Rádio	DUPLO TRIODO	(7)RCA (7)РАДИО AАMПA
6U8A	4		RF	B9A	Rádio	TETRODO	(4)TOSHIBA
C3M	6		AF	B8B		PENTODO	(6)TELEFUNKEN
CV3884	6		AF	B8A	ECC40	DUPLO TRIODO	(6)foreign made(???)
E80CC	9	4	RF AF	B9A	Próxima da ECC87, conferir diferenças.	DUPLO TRIODO	(4)PHILIPS (5)WESTINGHOUSE
E83F	1		AF	B9A		PENTODO	(1)SQ
EAF42	5		RF AC	B8A	6CT7	Single diode variable μ pentode with a common cathode	(5)MINIWATT
ECC40	88		AF	B8A	CV3884	DUPLO TRIODO	(12)TUNGSRAM (76)MINIWATT
ECC81	5		RF	B9A	12AT7	DUPLO TRIODO	(5)MINIWATT
EF12	4		RF AF	FOOTLESS		PENTODO	(4)TELEFUNKEN
EF40	107		AF	B8A	Sucessora da EF12, conferir possibilidade de fazer mic.	PENTODO	(107)TUNGSRAM
EF41	19		RF	B8A		PENTODO	(2)MINIWATT (10)NATIONAL (8)TUNGSRAM
EF42	114		RF	B8A		PENTODO	(114)TUNGSRAM
EF89	6		RF	B9A		PENTODO	(6)TELAM
EL34	16		AF	IO	6CA7	PENTODO	(4)TESLA (6)UNITED (6)RSD
EL41	13		AF	B8A		PENTODO	(10)TUNGSRAM (3)ORION

EF12 PICS

VALVE 1:







VALVE 2:








VALVE 3:









VALVE 4:







---

ORIGINAL POST:

Hello there guys!
Not sure if this is the right place for this topic, so please let me know!

Here’s the deal, I just found 4 Telefunken EF12’s, all 4 completely new, unopened, super well protected steel valves in an old university radio station and a whole bunch of other valves, 100’s, but I know those are the really rare ones in this treasure!

I’m an eternal beginner to DIY but at the same time I do dream about being able to make my own stuff, almost impossible in today’s brazil and in my situation, but anyways, here it is.

What do I do???

Cheers!

 

[moamps]

Not a good place, maybe the administrators will transfer your post to the drawing board.

Using the EF12 tubes you can make a microphone preamp, something in the style of IRT V41. You can find the schematic here:
http://audio.kubarth.com/rundfunk/index.cgiEF12 can also be used as an impedance transformer in condenser microphones.
You need to list all the tubes (maybe some are more expensive than EF12) you have and probably if you sell the ones you don't need you will earn enough to finance such a microphone preamp project.

 

[MaxDM]

my favourite microphone tube. I prefer it to any tube I have tried in a U47, including a couple of old VF14's

Also, the V41 is a fantastic-sounding circuit, and it can easily be made to be flatter on the bottom end.

 

[mateus]

Not a good place, maybe the administrators will transfer your post to the drawing board.

Using the EF12 tubes you can make a microphone preamp, something in the style of IRT V41. You can find the schematic here:
http://audio.kubarth.com/rundfunk/index.cgiEF12 can also be used as an impedance transformer in condenser microphones.
You need to list all the tubes (maybe some are more expensive than EF12) you have and probably if you sell the ones you don't need you will earn enough to finance such a microphone preamp project.

That would be amazing!!

Lemme post here all I got so far.

MODELO QTD
12BY7A 6
6AL5 15
6BQ7A 8
6CA7 77
6SA7 5
6SK7 3
6SN7 14
6U8A 4
C3M 6
CV3884 6
E80CC 9
E83F 1
EAF42 5
ECC40 92
ECC81 5
EF12 4
EF40 105
EF41 19
EF42 14
EF89 6
EL34 16
EL41 13

As I was talking to another friend, I have been going around so much with the idea of building stuff I would never be able to get my hands on that it would be amazing if I could find a way of trading some of this stash for some of these amazing kits we have around the community!

 

[moamps]

As I assumed your stash is worth a lot of money, 2000-4000 Euro or more depending on the condition of the tubes and brands, especially these

6CA7 77
6SN7 14
E80CC 9
ECC40 92
EF12 4
EF40 105
EL34 16

One 6CA7 or EL34 Philips in new condition costs more than 50 Euro.

 

[mateus]

Maybe I could build or loan a tester and check one by one? Is there any tester circuit around?

 

[moamps]

https://www.dos4ever.com/uTracer3/uTracer3_pag11.html

 

[mateus]

https://www.dos4ever.com/uTracer3/uTracer3_pag11.html

Cool! The site says there are 5 of these in Brazil, I’ll try checking if I can locate any of these close to me.

 

[abbey road d enfer]

Cool! The site says there are 5 of these in Brazil, I’ll try checking if I can locate any of these close to me.

This tester will tell you only the basic parameters, such as slope/Ra/Mu,but it won't tell you how good it is for audio, particularly if you want to use it in a mic head amp, where noise and grid current are paramount.
To my knowledge, these parameters have always been tested in a circuit that mirrors the intended application.
I don't think this tester tests grid current.
It would help you sorting the wheat (tubes that work) from the chaff (those that don't), but the final judge will be plugging them in a real circuit.

 

[mateus]

Got it! I doubt I’ll have a chance of having the real deal circuit at hand to test those unfortunately, but I would love to! Is there someone out there selling a mic kit for a u47 or some other one in wich I could test those?
The blant honesty is I don’t have the money for affording such things right now, too many taxes, brazil money worth nothing now a days, etc., but I would gladly get into trading so I could end up with some new gear. Maybe some serious builder would be interested in something like this?
Cheers!

I will do my best into cataloguing (not sure this word exists) all of them with all info I can gather.

 

[Winston OBoogie]

As I assumed your stash is worth a lot of money, 2000-4000 Euro or more depending on the condition of the tubes and brands, especially these

6CA7 77
6SN7 14
E80CC 9
ECC40 92
EF12 4
EF40 105
EL34 16

One 6CA7 or EL34 Philips in new condition costs more than 50 Euro.

Yep. And although there are only 6 of them, his C3M's (nice tubes) are worth about 25 Euros apiece if NOS. It all adds up

 

[moamps]

This tester will tell you only the basic parameters, such as slope/Ra/Mu,but it won't tell you how good it is for audio, particularly if you want to use it in a mic head amp, where noise and grid current are paramount.
To my knowledge, these parameters have always been tested in a circuit that mirrors the intended application.
I don't think this tester tests grid current.
It would help you sorting the wheat (tubes that work) from the chaff (those that don't), but the final judge will be plugging them in a real circuit.

I suggested this tube tester because it is necessary to check the condition of all other tubes except EF12, especially 6CA7 and EL34 which are probably the most valuable and easiest and fastest to sell. For such a purpose, this tester would be more than enough.

 

[abbey road d enfer]

I suggested this tube tester because it is necessary to check the condition of all other tubes except EF12, especially 6CA7 and EL34 which are probably the most valuable and easiest and fastest to sell. For such a purpose, this tester would be more than enough.

Agreed. Making paired sets (pairs, quads,...) would allow selling for more.

 

[cyrano]

I suggested this tube tester because it is necessary to check the condition of all other tubes except EF12, especially 6CA7 and EL34 which are probably the most valuable and easiest and fastest to sell. For such a purpose, this tester would be more than enough.

Why no need to check the EF12 tubes?

I have one of those. Came from one of several containers tubes that were sent to scrap when my local electronics supplier (in Antwerp, Mandola) stopped doing business two decades ago. Nobody wanted those tubes.

I collected some, until the police stopped me...

 

[mateus]

On the EL34 side there's 77 6CA7 (Samsung-NEC) and 16 EL34 (4 Tesla, 6 United and 6 RSD).

On the 6SN7 there's 7 RCA and 7 РАДИО AАMПA.

On the E80CC there's 4 Phillips and 5 Westinghouse.

On the ECC40 there's there's 12 TUNGSRAM and 76 MINIWATT.

On the EF40 they're all TUNGSRAM so far.

More to come.

PS: The 6SN7's are of the same brand of those 6SA7s and almost exact box.

 

[mateus]

Sold some already, gonna edit the 1st post with total findings and what's still up.

 

[mateus]

Managed to make some good pictures of the EF12s but I'm no photographer, so don't blame me.
Still couldn't find someone, close to where I am, with a good and regulated tester however examining those tubes really close they really seems as they have never seen any kind of use, nor the pins nor the center socket thing have no sign of use.

 

[PermO]

What an amazing find ! congratulations !

 

[mateus]

What an amazing find ! congratulations !

Thanks man! High hopes they can help me making some cash for some new dream gear!

Found some interesting data about the metal RCAs 6SN7s today, since a friend here asked about them.

Repeated Buyers described they are great sounding. "The sound is wonderfully sweet and very good bass! Simply wonderful !" RCA Brazilian Technology quite different from all other 6SN7s 2A3

Other ones are Russian, Foton factory originated. All of them looks to be completely NOS and are in pristine condition, not even slight markings in pins or central lug.

Cheers!

 

[mateus]

Took some pics of the C3Ms.