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Penegal 15th January 2012 12:45 PM

6E2 vacuum tube compatibility
Hello, everybody.

I am considering buying a vacuum tube amplifier, which includes a 6E2 (EM87) magic eye for retro look, and I wonder if I could safely exchange this tube with the pin-compatible EM85? By safely, I mean without any modification of the amplifier device.

For memory, here are these tubes data sheets :
Thank you in advance.


DF96 15th January 2012 02:12 PM

You might need to change the resistor on pin 9, the triode anode. EM85 says 470k, EM87 is 100k. Failing to do this probably won't do any harm, but the indication may be wrong (e.g. cramped at one end of the range).

Jebem 15th January 2012 02:18 PM

They have the same pin out and similar electrical working voltages, so it should be possible to use either one without circuit modifications.

Penegal 15th January 2012 04:31 PM

If I understand, changing the 6E2 with the EM85 will lead to an decreased sensitivity of the magic eye?

In this case, can I put on of these tubes instead of the furnished 6E2 :
They seems to be pin-compatible, as they have both noval pin, but I have to admit that my electronics learning are far in my college years.

By the way, if somebody knows a magic eye tube which has a shadow sector pattern and is pin-compatible with 6E2, I'll take it! :D

the_manta 15th January 2012 05:14 PM

EM85 is very rare and was used in some Schaub-Lorenz and SABA radios. It is really a better idea to hand them over to some collectors or something.

Why don't you use russian magic eyes ? There are tons of them out there. 6Е1П has a nice shadow sector pattern and is available from ebay. Here is a nice page where you can see nearly every magic eye ever produced.

Penegal 15th January 2012 06:15 PM

6Е1П (EM80)? Да, товарищ:rolleyes:; nevertheless, do its characteristics fits to replace an EM87 tube without any modification of the host circuit? No sensitivity problem to expect?

Blaireau 16th January 2012 08:03 AM

To replace an EM87, you can directly use an EM84 or a 6Е2П without any problem. I've already tried that several times. The anode résistor was 470K in each case. The patterns are quite similar, although not always perfectly centered, by this little defect is inherent to the eye's machanical construction. In a stereo amp, the main difficulty will be to find two eyes whith exactly the same pattern. EM84-6E3P

Penegal 16th January 2012 04:36 PM

Concerning the EM84, I was under the impression that it has a similar pattern than EM87, and yet I would like another pattern than the light band pattern of EM87, something similar to EM80 (preferably), EM81 or EM85; is the 6Е2П tube matching with what I'm looking for?

Blaireau 16th January 2012 05:43 PM

"is the 6Е2П tube matching with what I'm looking for? " Sorry, I made a confusion between 6e2p and 6e3p. 6e3p has a pattern which is similar to EM87 and EM84. (variable length luminous strip) 6e2p is really different, more looking like a magic eye.

Penegal 18th January 2012 06:27 AM

Er... You lost me here : are some of these tubes matching with what I'm searching?

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