Thats more like what I was looking for. Simple and appears to be effecitve enough. Just a bit worried the feedback will delete or nulllify the mumbo jumbo of the germaniums. Oh well Ill try and create
In the time of germanium transistors PNP was king.. TO3 Transistors had a3mm thick copper housing.Base to emmitter voltage was about 0,3 V. Still nowadays they use germanium Diodes for HF rectification..low threshold voltage and smooth transition from non conducting to ON similar to a thermionic tube. The problem was .. if a germanium transistor reaches a temperature above 75 degrees centigrade it will thermally runaway into selfdestruction.At ambient temperature of..say 35 degrees you have another 35 until failure, with silicon in TO3 you have 200 degrees to failure thats a margin of 165degrees. whats it about: you can replace low power AC or OC..(germanium transistors) by BC or 2SA 2SC(silicon transistors) by doubling the value of the resistor thats between the base and the emitter. if there is AA118 or like that..try a schottky diode.
MULTIWATT TW40 Junior - amp 25w class B KU606(Si)+4NU74(Ge)
https://www.elektroakustika.cz/images/tesla/tw40/tw40_3.jpg
https://www.elektroakustika.cz/images/tesla/tw40/tw40_3.jpg
In its time the 1970 ,s Goodmans used to make a receiver the 3000 series this used Germanium output transistors and silicon drivers As indeed did the Armstrong 400 -500 series ! They sounded very good about 15-25 watts output into 8 ohms
I always thought that the Goodmans unit sounded very nice for the money
Trev
I always thought that the Goodmans unit sounded very nice for the money
Trev
Germanium output transistors have engraved themselves into my brain as being unreliable and a loose cannon since a friend of mine brought to me an amplifier of German manufacturer Saba or Grundig (don't recall exacty which…) in the 1970ies whose AD149 power devices had been blown by operating the unit without any load 
!
Best regards!
!Best regards!
Blown without any load most doubtful unless the amplifier had an unloaded output transformer ! When used within their power ratings they were ok
Remember these were first generation devices and designers had yet to fully understand their art
Leak stereo 30 /truvox tsa100 armstrong 421 would have been germanium and are now 60 years old many are still working I have them in my collections
Not a bad record
Trev
Remember these were first generation devices and designers had yet to fully understand their art
Leak stereo 30 /truvox tsa100 armstrong 421 would have been germanium and are now 60 years old many are still working I have them in my collections
Not a bad record
Trev
Yes, I was scratching my head also as the unit had no output transformers! Most probably it's stability was marginally - and well beyond it's margins without load. Which may or may not have had it's cause in the Ge power devices. As a school boy I didn't own an expesive oscilloscope those days so had not been able to investigate further on it.
Best regards!
Best regards!
Maximum allowable collector-emitter voltage (Uce): 45 V
Maximum DC Collector Current (Ic): 15 A
Operating Junction Temperature (Tj): 110 ° C
Cutoff frequency of current transfer ratio (ft): 0.05 MHz
Static current transfer ratio (hfe): 20
Low gain, low cutoff frequency. Temperature properties are worse than those of silicon.
The classical quasi-complementary Lin scheme will suit you
Maximum DC Collector Current (Ic): 15 A
Operating Junction Temperature (Tj): 110 ° C
Cutoff frequency of current transfer ratio (ft): 0.05 MHz
Static current transfer ratio (hfe): 20
Low gain, low cutoff frequency. Temperature properties are worse than those of silicon.
The classical quasi-complementary Lin scheme will suit you
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