ECL82 amp from old magnetophones

[sarnica]

Hello Guys,
I recently bought 2 pcs. identical "Hornyphon" magnetophones made in Austria with the idea to build with them a stereo tube amplifier. I want to use only the last stage of the amplifier build with the tube ECL82 and the magic eye EM84, but it seems that the schematic is quite complex for me and I can't decide what components to remove. Can you give me some advice, please?

 

[Eli Duttman]

For your audio project (which should be dual mono, even if it's built on a single chassis) the power transformers, the EZ80/6V4 rectifiers, and the ECL82/6BM8 signal tubes migrate. The O/P transformers are not up to HIFI service.

You could research and build a power O/P indicator around the EM84 "magic eye", but that is (IMO) just fluff.

You will obtain about 2 WPC. Very, sensitive speakers are needed for a satisfactory listening experience.

By all means, save the ECC83/12AX7s and EF86s for future projects, like a phono preamp.

I'll try to get back to you later with something based on an old Mullard design.

 

[BinaryMike]

I would harvest only the iron-core transformers, tubes, and possibly the line voltage selector. The indicator lamps and associated hardware might be useful if they look attractive to you. There are folks who find value in old resistors and capacitors, but I'll let them speak for themselves.

 

[VMUNIX]

Rewire it to look like this:
Three Watt Economcal Stereophonic Amplifier

 

[Ketje]

It's spring so let us clean-up
Mona

 

[jean michel]

hello ,

simple build ...

so easy build

 

[sarnica]

It's spring so let us clean-up
Mona

Thank you!
I was considering almost the same configuration, but without ECC83. Can I connect the input signal directly to ECL82's triode? I will use the amplifier with my laptop or smartphone. R33 is for Tone control, isn't it? And what do you think, how much power can I get from this amp?

 

[Ketje]

With R35 = 1M you need double the drive for the output tube, what is needed for the magic eye.To compensate for the loss that is where the extra triode comes in.
If R35=1k then 1 triode will do.But the eye doesn't do so well.
The output of a ECL82 is something like 3W.And yes R33 cuts more or less high notes.
Mona

 

[planet10]

http://www.diyaudio.com/forums/tubes-valves/213807-ecl82-single-tube-amp.html#post3047354

dave

 

[sarnica]

With R35 = 1M you need double the drive for the output tube, what is needed for the magic eye.To compensate for the loss that is where the extra triode comes in.
If R35=1k then 1 triode will do.But the eye doesn't do so well.
The output of a ECL82 is something like 3W.And yes R33 cuts more or less high notes.
Mona

I prefer the simple design, so the magic eye and ECC83 goes away, R35=1k and hope that is all. Hope, that the output transformer , that have been made by Philips has high quality and sounds as it should. By the way i have an amplifier from vintage German vinyl player with a single tube ECL86, that sounds great. Cheers!

 

[Eli Duttman]

Thanks to Jeff Yourison, I am able to upload the files I mentioned earlier.

If the O/P transformers from the tape machines get reused, full pentode mode is the only realistic option. Open loop linearity in full pentode "finals" is maximized by regulating g2 B+ at a substantial fraction of anode B+.

 

[jean michel]

hello ,

old série's ECL ...

i not build ECL 82 , just ECL 86 and proto ECL 805 ...

i build the ECL 82 to mode UL later ...

 

[sarnica]

Thanks to everybody, that take a part in this project ! I would like to keep the primary scheme, because the O/P transformer is quite specific, and I want to keep the power supply also. Of course there are unlimited options for different schemes, but the idea in the project is to use what I have, not to build something new. At this point with the help of Mona (Ketje) we have this scheme and I hope to hear and other opinions about is it possible to improve it with some small changes?

 

[alejon]

Hi,
I've got the same idea as you, this is how I found this thread. May I ask you if you have done any progress with your ECL82 tube amp? Does it sound good? Thanks in advance! Regards, alejon

 

[Kay Pirinha]

Anybody noticed in this old thread that the schematics and the R2R in the pic most probably don't relate? The schematics belongs to a Philips EL3541, aka RK 14, which is a one speed (3.75 in/s)/four track machine, while the pic shows a three speed device, which most probably needs three different equalizations. Also the manufacturer is another one, as yet stated in the title, and the Hornyphon shows an EM80 or EM85 instedad of an EM84.


Best regards!