Help identifying a Telefunken(?) tube... - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 26th January 2011, 12:05 AM   #1
pyrotas is offline pyrotas  Italy
diyAudio Member
Join Date: Jan 2011
Default Help identifying a Telefunken(?) tube...

Dear all,

I have found a very old tube, with noval socket, which I believe is a Telefunken. Markings are almost all gone, only the top triangle of the logo and the "EC" letters remain. At the bottom, a diamond shape is engraved in the glass. Plate is nowhere similar to twin triodes such as 12AU7 which seems to suggest me this is *not* a twin triode I attach a zip with some pictures which could help.

Anyone knows what this tube is? Any help would be greatly appreciated!

Thanks in advance
Attached Files
File Type: zip (725.2 KB, 81 views)
  Reply With Quote
Old 26th January 2011, 01:16 AM   #2
singa is offline singa  Singapore
diyAudio Member
Join Date: Apr 2004
Location: near
Send a message via AIM to singa Send a message via MSN to singa Send a message via Yahoo to singa
Default and

Hi, As far as I can see it has two anode stuctures so it's should be a twin
triode.Most probably ECCXXXX and if you say it's not ECC82/12AU7
then a ECC83? 81? just test with meter for continuity of pin4,5 which is the

Just wire it up and test if it amplify a signal.Just don't exceed anode
voltage of 300V for signal tubes. Singa.
  Reply With Quote
Old 26th January 2011, 01:16 AM   #3
diyAudio Member
Join Date: Nov 2010
I don't know if its my computer, but everytime I click on the attached file, my media player opens up. You can post pictures directly.
  Reply With Quote
Old 26th January 2011, 01:35 AM   #4
diyAudio Member
Join Date: Nov 2007
Location: Nelson, NZ
Looks identical to Telefunken ECF82 (==6U8) triode pentodes that I have here. Mine have a getter flash on the glass over the aperture in the pentode plate which makes it hard to see there, but the rest is identical.
The triode plate looks like it is bent and separating as well, but it might just be distortion in the pic.


Last edited by rotaspec; 26th January 2011 at 01:43 AM.
  Reply With Quote
Old 26th January 2011, 01:44 AM   #5
gullaz is offline gullaz  Italy
diyAudio Member
Join Date: Jul 2010
Location: bologna, italy
Looks very similar to an ecf82... must have an ecf82 tfk somewhere, I see if I can find it to compare with your pictures.
  Reply With Quote
Old 26th January 2011, 07:43 AM   #6
diyAudio Member
Join Date: Aug 2008
it is an ECFxx for sure. A smaller triode structure alongside a bigger small signal pentode.
  Reply With Quote
Old 26th January 2011, 07:45 AM   #7
pyrotas is offline pyrotas  Italy
diyAudio Member
Join Date: Jan 2011
Default Yay, thanks!!!

Thank you all for the replies! If the bend is the one displayed in IMG_3111 yes, it is there. Does it mean the tube is near the end of its life ? Concerning the audio-test, I am currently playing with a "Valvecaster" project which runs tubes in starved plate mode with 12V anodic voltage. I have indeed already tried it in my circuit (just crossing fingers and hoping not to blow out the whole house) works, flashes at the beginning and amplifies the signal. It has the lowest gain I have ever had in this circuit - sounds essentially clean even at "maximum gain". Sound is smooth and velvety and...well...I just love it! The only problem is I don't know the heater voltage: currently I apply 12V between pins 4 and 5, gotta see if this is OK or there's risk to burn it down. Possibly the circuit would need to be adapted a bit if this is not a twin triode but...just sounds great for clean tones!

I attach the schematics for the "Valvecaster" if anyone is interested.

Thanks again!

Attached Images
File Type: gif MatsuminValveCaster.gif (18.3 KB, 140 views)
  Reply With Quote
Old 26th January 2011, 07:46 AM   #8
pyrotas is offline pyrotas  Italy
diyAudio Member
Join Date: Jan 2011
Forgot to mention that! The tube warms up much more than any other double triode I have ever tried in my circuit...
  Reply With Quote
Old 26th January 2011, 08:00 AM   #9
diyAudio Member
mastodon's Avatar
Join Date: Jan 2011
Yes, most likely ECFxxx, but another possibility is an ECHxxx. Check if the cathode of the triode and the pentode/heptode are connected. If so, it's more likely to be a triode/heptode combination (ECHxxx). But due to a lack of shielding, I think ECFxxx is more likely.
  Reply With Quote
Old 26th January 2011, 04:38 PM   #10
diyAudio Member
Tubelab_com's Avatar
Join Date: Jul 2005
Location: West Virginia panhandle
It looks like a member of the 6U8 triode / pentode familly to me too. It probably has a 6.3 volt heater and it won't live too long on 12 volts.
Tubelab, it's 5 year mission. To explore strange new tubes, to seek out new circuits and topologies, to boldly go where no tube has gone before......
  Reply With Quote


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Telefunken V69B - Tube Amp refference Tubes / Valves 11 1st January 2009 07:56 PM
Telefunken Consoles: not just for tube and iron scavenging! pjanda1 Tubes / Valves 3 20th August 2008 09:40 PM
WTT: One Telefunken EF804 tube for one WE 5842/417A GordonW Swap Meet 0 15th April 2008 02:00 PM
telefunken EL 34 audio tube first Tubes / Valves 3 27th September 2007 06:36 PM
Telefunken Console Tube Receiver (stereo): $75 pjanda1 Swap Meet 5 22nd September 2007 10:21 PM

New To Site? Need Help?

All times are GMT. The time now is 07:32 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2