Recycling - giving old equipment a new life.

[Disco Volante]

I notice a neg grid bias supply of -17 v for the output stage grids and a reduced voltage for the input to the phase splitter. There are several bias adjustments and a NFB pot across the OPT secondaries.

Oddly, the NFB pot is mounted on the front fascia as a bass control, and the winding has a bit of DC applied to it...
Never seen anything like it.

 

[Disco Volante]

Bear in mind: Don't expect this to have really low distortion. 3% ain't bad for something like that. AND you're going to need an additional 2 output transformers to even safely bench test for distortion, and run speakers, given the outputs are at B+ voltage ref to ground.

You have a short wave, AM, long wave, FM radio. I'd keep it.

I suggested a 70 volt 10 watt distribution PA matching transformer as they have multiple taps to hook up a speaker. You need 800 ohms to see it. But you could also hook up an 800 ohm load resistor and use a 2 channel scope to read the voltage and see the waveform. Or use a DMM with 20K freq response as a floating meter, no ground, across the resistor. Square the voltage and divide by 800 to get the power out in watts. Or use blocking capacitors after the load to allow grounded bench equipment to read the output.
Lots of ways to figure it out.

I hope you get some fun out of it. Good luck.

Hope you get some fun out of it.

Thanks a bunch for the tips. I have scope and sig gen and a good DMM.
Might eventually wind a couple of small OPTs for it, I have a couple of EI54 bobbins floating around somewhere..
Cheers

 

[rock soderstrom]

Wow, I found a couple of ladies online, ähhmm I mean I found a Grundig TK24, it was very cheap and the "schicken Fräuleins" quickly convinced me to buy another Grundig Tk.


Huh, does anyone recognize their grandma in the photos?

Back to the topic:

The general condition is okay, unfortunately the Tolex and the piping have a few problems, the rear plastic grille for ventilation is unfortunately also broken, which often happens.

The components are nice, the PSU transformer is very good, we find an EF86, ECC81, EM84 and two EL95 (one as SE 2.5W power amp, the other one drives the record head). What should I do with all those EL95s? Tubes are mostly Valvo sometimes Telefunken.

Anyway, a nice 8€ catch, not just because of the "Fräuleins"

 

[Mr. Moscode]

Those girls could be your grandma or great grandma. But yeah to the politically incorrect marketing! Have fun!

 

[Disco Volante]

two El95's would be about 7W in PP... With a couple of EF91s you could make a mini-Quad II? Except you'd have to roll your own fancy OPT with cathode windings...
Or a quad for 14W in an unreasonably complicated way..
They're cute with their little 7-pin fassungen.

Nice find!

 

[rock soderstrom]

Yeah, they are really cute...

Perhaps the EL95 can (almost) replace the 6K6GT in the original 6G15 circuit? I should try that out, I have plenty of suitable 5 Ohm (secondary) OP transformers from the Grundig TKs.