one stereo output transformer??

Greetings,

 

I am a new member with Radiomuseum and I live in the United States. I am a Ham operator and tube hobbyist. I have restored many amps and tuners form the US. I have just recently started to work on a beautiful Emud console stereo, model #910. I have the schematic and I have this question. The way the schematic is shown is a bit different from what I am used to here in the US. Can anyone help me understand the Europeon schematics. My main question is how the switches are displayed and identified. On the schematic that I have, it shows the switches with numbered circles and there is a table with dots that somehow correspond to the different switches. The switches are not actually named on the schematic. Can anyone help me understand how to put these two pieces of information together to identify the swiches in the schematic? Also, in the US we often have two seperate output transformers for a stereo amplifier. It appears that this chassis has only one OT. Am I to assume two seperate windings in this transformer? It also appears that the negative feedback is taken from a seperate tap on the transformer....is this also common? Anyway, I find the unit to be very nicely built and am looking forward to getting it operational...it's just a little different from what I am used to so any help would be greatly appreciated. Please excuse my dumb questions.

Thanks,

 

Gregg Ruecker

 

edited the title

To thank the Author because you find the post helpful or well done.

Hallo Gregg, welcome aboard. I hope, You might find a few english speaking friends giving You support with Your Emud set - You might find, there is a larger part of the community german speaking, that will say, not so familiar with english... In some cases, we might try to translate Your requests to reach german speaking members to help You.

Usually, the best way to get help in restoring a certain set, You post Your request from the corresponding model page, so open the Emud 910 page and use the "Uploads and questions" and then "Information and question" link to post a new forum text, that will be linked to the model.

Here, Your request might get lost, as other members will expect a news members introduction test.
Kind regards / 73 Martin

To thank the Author because you find the post helpful or well done.

Hello Greg,

for understanding the switching table I'll show you two examples from this model:

this is a part of the table:

In case, the switch is in FM position (or in AM, Phono, Tape position)

these alternating points of the switch would be connected:

 

 

The next picture shows the situation, if the switch is in SW position.

The dot means: alternating points are connected by the switch. To read the schematic, it might be a good idea,  to print it several times for each possible position of the switch an fill in the connections corresponding to the table for each position, one for FM, one for SW and so on. Its then much easier to understand what happens.

As I don't know the model and its output transformers, I keep this thread as an open question and invite more competent people to answer this part of your question.

yours

Martin

I'll move the thread to the modell

 

To thank the Author because you find the post helpful or well done.

Hello Gregg,

there are 2 output transformers. The lower is used with 2 EL84 pushpull in mono mode. The upper and lower are used in stereo mode with only one EL84 per channel. This radio is a mono receiver with stereo amp for disk drive and tape input.

I hope this answers you question,

regards, Heribert

To thank the Author because you find the post helpful or well done.

Welcome aboard Gregg!

I hope you enjoy the very good quality of posts in this forum. I look forward to any interesting findings you might like to share here too. The interest range is quite broad, from cabinet finishes to the finer points of RF circuit techniques.

The stereo system in your Emud 910 is accurately summarized by Heribert.

A few years ago I came across an article in Popular Electronics 1959 describing a very similar stereo system used by CBS. They called it the CBS Stereo Simplex. This link explores the operation of this efficient stereo amplification method and compares it to a contemporary 3 channel stereo system that was used extensively by Motorola, and in at least one Grundig set.

Regards,

-Joe

To thank the Author because you find the post helpful or well done.