Telefunken Magnetophon 85 --> EL95 Guitar amp - diyAudio
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Old 27th February 2011, 02:32 PM   #1
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Default Telefunken Magnetophon 85 --> EL95 Guitar amp

Hope this is in the right part of the forum.



What I have is a Magnetophon 85 with a fairly functional amplifier section.
I'd like to turn it into an EL95 guitar amp.

What I basically would like to know is how self contained that amplifier section is. It'd be great if all I had to do was to hook up the power transformer, though I have my doubts that it'll be that easy.

I've not modified a valve based system before but I've replaced capacitors, rectifiers, etc.
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Old 27th February 2011, 05:40 PM   #2
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I have three of those

If you need a schematic, I have it.

But I would not damage the functioning AEG/Telefunken M85, since it is one of the best from it's age.
(frequency response up to 16 kHz, absolutely great quality mechanics etc. etc.)
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Old 27th February 2011, 06:05 PM   #3
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Thanks Artosalo.

My initial tests of the machine didn't seem too promising. Maybe I'll give it another chance.
The EF86 valve in there is very, very microphonic and I was wondering if and where you can still get those.
For sure there are leaky capacitors in it.
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Old 27th February 2011, 07:35 PM   #4
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Old tape recorders need to used regularly, otherwise their many switches and relay contacts get oxidation and the operation is poor or inadequate. I strongly recommend to clean all contacts and just after that evaluate what it is.

I noticed that after prover service M85 will perform grandly.

EF86's are available easily. Search from net, but check first the contacts of the socket of EF86.
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Old 27th February 2011, 10:00 PM   #5
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It's pitty to destroy Telefunken M85 and according to photos it's in really good shape.

EF86 and capacitors could be found easily and it's not big effort to replace.

A bit problematic could be if you want to find Telefunken's EF86, pretty scarce and expensive!

You can try EF86 / 6267 Siemens, EF86 / 6267 Valvo or EF 86 Philips which are common NOS types and also some cheaper RFT or Tesla EF86.
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Old 28th February 2011, 09:19 AM   #6
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Thanks a lot for the replies.

What are some of the crucial components that usually need to be replaced. All the capacitors ?
what I'm asking is: is there something that with 100% certainty needs to be replaced ?

There's a lot of hum and when I turn down the bass it sounds almost like a tremolo on a guitar amp.
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Old 28th February 2011, 11:38 AM   #7
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[QUOTE]is there something that with 100% certainty needs to be replaced ? /QUOTE]

No. For example, I did not need to changed any component. Just clean and adjust some.
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Old 28th February 2011, 06:53 PM   #8
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Thanks Artosalo,

I cleaned everything as good as I could and it made no difference.

Just checking the capacitors with a meter and I'm getting a lot of very bad values. All the paper ones are off the chart and the electrolytics don't look too good either, so this looks like an almost complete recap. Can a bad capacitor under the EF86 cause microphonics ?

Now I'd be really interested in that schematic Artosalo.
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Old 28th February 2011, 07:06 PM   #9
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Quote:
Now I'd be really interested in that schematic Artosalo.
I sent you a message concerning this.
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Old 21st September 2011, 05:24 PM   #10
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Hi,
I recently acquired a pair of amps from 2 magnetophon 85.
I have some questions about the wiring.
There are 3 free cables coming out from the transformer, blue, red, and green. I suppose that is the speaker output. Do you know the connections?
Normally 2 cables are needed. I suppose that probably 2 speakers were connected.
All the other connections are made by a noval plug. Do you know the connections?
I think I find some connections:

Pin 1 unknown
Pin 2 input
Pin 3 not connected
Pin 4 not connected
Pin 5 unknown
Pin6 unknown
Pin 7 Heater
Pin 8 Heater
Pin 9 Ground

So, I miss Pin 1, Pin 5, Pin6.
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