Today’s quiz. The three attached pictures are oscilloscope traces of three audio preamps producing a 10KHz square wave into a high impedance load. One is a 1980 Audio Research SP-6B (38-year old tube preamp), there is also a 55 year old germanium transistor preamp and a 40 year old Japanese tube preamp. Which is which and why?
Image #1?
Image #2?
Image #3?
Image #1?
Image #2?
Image #3?
An externally hosted image should be here but it was not working when we last tested it.
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It’s all possible to have so many factors affect the square wave trace. The date and origin is of less importance. So just a WAG.
#1 is Japanese tube because it is so smooth and quiet it probably has a lot of filtering typical of tube products by Japanese market who like that sound of smooth and midrange shout.
#2 is Ge preamp because it has some low level noise indicative of high speed bandwidth device is inherently capable of.
#3 is AR because it has overshoot, typically there on designs that try to impart “high resolution” detailed sound.
#1 is Japanese tube because it is so smooth and quiet it probably has a lot of filtering typical of tube products by Japanese market who like that sound of smooth and midrange shout.
#2 is Ge preamp because it has some low level noise indicative of high speed bandwidth device is inherently capable of.
#3 is AR because it has overshoot, typically there on designs that try to impart “high resolution” detailed sound.
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