DKE one tube

I have a DKE, in working condition, which only has one tube (ECH4).  In researching I haven't found any info on a DKE one tube set.  Any information would be helpful.  You can see a picture of the chassis at  

Thanks, Gerhard

• Chassis of one tube DKE (86 KB)

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Dear Gerhard, in addition to Jacob Roschy explanations:

First of all please have a look at a DKE in original condition. Your radio is showing a lot of fundamental changings. DKE 1938 in it´s first edition was operated by a single way rectifier tube VY2 and a composite tube VCL11. The following (visible) changes were made on your DKE.
The VY2 had been replaced by a dry rectifier. The VCL11 (90 volt heater) had been replaced by a ECH4. The tube socket for ECH4 had to be replaced and a heater transformer for 4 Volt heater of ECH4 had been added.. The original mains resistor is missing. A hum potentiometer had been removed. The plug connector for antenna and earth, the power Switch, the two capacitors 4μF at the left side and the wiring are not original.

Reiner

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Hello Gerhard,

the ECH4 is a triode-heptode frequency converter tube, which someone took as a makeshift substitute for the then unavailable original triode-output-tetrode VCL11. The triode unit of the ECH4 may have been used in the same way as the VCL11 triode unit, while the heptode unit of the ECH4 substituted the output tetrode section of the VCL11.

As well the rectifier tube VY2 was substituted by a selenium rectifier as obvious on your picture.

As all this was the creation of a radio service man, it's no wonder that you didn't find any “official” information.

Best Regards,

Jacob 

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