How to adapt mag.eyes like EM34 or EM85

Omer, a new member from the U.S. would like to get an answer on this topic:

Even though I haven't become an official member yet, I might suggest a page or a link on your site that shows how to adapt an em34 socket to use a 6E5C tube or a link that shows how to adapt an em85 to a em80. The way vacuum tubes are available and the way audiophools are jacking up NOS tubes, I think there should be a discussion on solid state rectification as well, circuitry that wouldn't harm the vacuum tubes on start up as replacement modifications to keep old radios running. Vacuum Tube Valley in California has some recommendations.

For the discussion on solid state rectification he will open a new thread (I hope).

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The following is taken from my homepage and translated into english:

EM34 -> 6E5C

Usually both screens of the EM34 are used parallel. Therefore you´ll find two resistors mounted from PIN5 (L)to PIN3 (a1, d1) and from the same PIN5 (L) to PIN6 (a2, d2).

6E5C has only one screen hence only one resistor ( 1 MegOhm) will be used:

One Resistor is mounted from PIN6 (L) to PIN3 (A).

PIN6 (L) gets the wire which was originally mounted to PIN5 (L).

PIN5 (G) gets the wire which was originally mounted to PIN4 (G).

The socket has to be turned by about 45 degrees since the 6E5C Screen is aligned different to the EM34 ones.

We recommend keeping a sketch of the original wiring with the set.

Pinning EM34:

Pinning 6E5C:

EM80 -> 6E1N

It is quite easy to swap a worn out EM80 with a new 6E1N. The pinning is identical so just replace without any changes to the existing wires. Bear in mind that the dimensions of the russian type are slightly different to the EM80 but in most cases this won´t be a problem.

EM85 -> 6E1N

This can be a tricky one since the EM85 has, in addition to the Magic Eye, a seperate Triode System which could be used for other purposes in your radio set. So please be carefully and check schematics first !

To avoid damages to your radio set we do not propose any changes here. 

Below are pictures and pinnings of EM85 and EM80, taken from Franks Tube Page which is highly recommended to any radio collector http://frank.pocnet.net/sheetsE2.html. Possibly you can find a way of changing wires for your set. Above example with EM34 may help.

EM85


EM80

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Ich habe dieses Mail von unserem Mitglied, Frau Marianne Gibson aus Santa Rosa, USA erhalten.
Hello Mrs. Gibson

EM34 = see in the above article
EBC41 = ?
EBF89 = 6FD12
EAA91 = 6AL5
EL95 = ?

What do you mean with "Mystic Mystro Connection" ? Do you mean the connection on the rear, it is for a cable-remote-control.

Regards to you
Wolfgang Bauer

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I am quoting the "Essential Characteristics" by General Electric:

EM34 = 6CD7
EBC41 = 6CV7
EBF89 = 6DC8
EAA91 = 6AL5
EL95 = 6DL5

This is in accordance with information from the German "Franzis- Roehren-Taschen-Tabelle", 11th edition

Kind regards
KoBi

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Dear Konrad
Thank you for the information.
I have entered those as equal types.

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Is it possible to buy a 6E5C tube in the US?  The only 6E5 tubes I have found so far do not have an 8-pin base.

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Please check out the site, http://www.thetubestore.com/ru-6e5c.html

You might want to check EBay too.

I hope that members of this forum again can make a collective offer to purchase vacuum tubes/valves for members, like last year!

I hope this helps.

Omer

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I've found a very comprehensive page concerning 'magic eye' tube substitutions.
It is called magiceyetubes com

The tube numbers listed in a 'green' color have been tested/verified, those in the color 'red' are from various published sources, but have not been tested/verified by the website author.

 

Using the information contained at that page, I decided to buy an inexpensive 6DG7 to replace the much more rare EM85 from a Ducretet radio I am repairing for a friend.  The 6DG7 is in fact an exact electrical match to the EM85 and works flawlessly.  I was able to purchase the 6DG7 for a mere $9 US from a vendor on the NET. 

 

Thank you,

Bob

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Dear Bob
According to our tube date pages, the only 6DG7 known to us, is a pentode, which is a noval base version of the well known 6BA6 / EF93. The pictures clearly prove, that this

pentode 6DG7

really exists, as well as it is mentioned in current data books.

Your sentence: "I was able to purchase the 6DG7 for a mere $9 US from a vendor on the NET." Looks to me as if you would get that pentode - but I might be quite wrong. Have you received the 6DG7 as a magic eye? What is the brand and where did you buy it if it is a magic eye?

In any case: We want to have full information (self efficient) here and not links - which may be true or may not be true, wich can be changed or deleted ... We don't want to build up link graves. I therefore have deleted that link. But because the site can be quite useful, I have written the name of it.

If you have information on that tube, can you please give it to Jacob Roschy or Otmar Jung? You find members eMail addresses in the member list. He will then create that new tube and you can upload the picture. You can also offer more tube data or replacement hints etc. Our tube pages should be most complete and reflect all known facts.

Would be nice if you would load up a new portrait picture of yours in the "normal size".

Thanks for your cooperation. You are welcome.

 

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Hello Ernst,

 Thank you for the information.  After reading the data you provided, the one I purchased most likely IS a pentode!  The brand of tube was not listed. I will let you know once it arrives.

This the base diagram they listed for both the 6DG7 and the EM85 (as well as others):

I had never heard of this supposed "eye tube" before reading about it at that website, but thought I would take a chance.

Thanks again,

Bob

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Helo all,

This magic eye thread is very interesting.

The Radio Valve Data Book, (Iliffe Books LTD London 1966) mentions the EM85 made by Brimar as an obsolete type, so there may have come some successor of this tube-type.

In  the Muiderkring Electronic Tube Handbook 19th edition 1981, the EM85 and 6DG7 are mentioned to be the same tube with different designation.

Duncan's TDSL mentions another one, the 6DH7, as identical or close to the EM85.

So it is possible that there are two different tubes with the same name:6DG7

Regards, Jan Terranea.

 

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Hi Ernst,

I have two brand new EM34 Magic eyes from Chelmer Valve.I was planning to use one in my beautiful Philips Royal Opera FDK543 that you kindly issued pictures of on the Radiomuseum. Unfortunately they are too wide in radius to fit the hole in the wooden cabinet. I therefore purged an 6EC5C from Germany for 25€ incl. shipping. It has a drawing with it how to modify the the connections on the socket and fits nicely.

Best gards,

Per.

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Be aware, the radius of the 6E5C is wider than an EM34 tube.  I would suggest going in and seeing why the EM34 tube/valve is not able to fit.

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Actually the 6EC5C is a little smaller and it fits perfectly. The problem is that the Valve has to fit inside the Philips plastic logo in the front of the radio.You are right that the original Philips EM34 is a little smaller than the 6EC5C, but by removing the filt inside the logo it worked.

Regards,

Per.

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