siemens: 11GW; with audio module replacement for UCL11

This schematic for the 11GW d_siemens_11gw_audio_module.pdf includes the internal schematic of a home made audio module replacement for the UCL11 triode/pentode. The module includes a LD1 power triode and a RV12P2000 pentode preamp wire as a triode. The module also includes a 350 Ohm power resistor to soak up 40V of heater power and leave 12V for each of the tubes in the module. Each tube in the module also has a shunt resistor at the heater for fine adjustment of 100mA and 75mA heater currents for the LD1 and RV12P2000 tubes respectivelly. A 250 Ohm resistance biases the cathode of the power triode, but without electrolytic bypass.

The original dial glass was broken. A replacement dial glass was made with a laser printout on acetate transparency, and sandwiched between two pieces of clear glass.

I added a 1meg bias resistor from the neg bias supply to the first audio stage because it would clip on loud passages. It sounds very nice now.
 

Comments invited,

-Joe Sousa

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Hello Joe,

please see also here:  and Mr. G. Richter shows mee an Place  with informations about  the  use of "Wehrmacht-Röhren"  or tubes from german forces.   Interesting   Infos from Austria  here:

 regards Hans

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