I was looking at yamaha A-1 integrated, and paying particular attention to the phono MC section.
It seems that the MM and MC phono amplifer uses a common circuit, only the MC seem to to have signal amplifier (?), instead of using the traditional step up transformer.
Just wondering what are the pro and cons using this method ?
Another thing is in vintage knob, it claim the input impedance of MC is 10 ohms, but I could not locate where the input impedance (is it R401(orR301), but that is 82K or did it base on the reflected amplification value wild guess 0.6u:82K => 1:136K ). So would someone please kindly point it out to me ?
Attached from vinyl engine pdf

It seems that the MM and MC phono amplifer uses a common circuit, only the MC seem to to have signal amplifier (?), instead of using the traditional step up transformer.
Just wondering what are the pro and cons using this method ?
Another thing is in vintage knob, it claim the input impedance of MC is 10 ohms, but I could not locate where the input impedance (is it R401(orR301), but that is 82K or did it base on the reflected amplification value wild guess 0.6u:82K => 1:136K ). So would someone please kindly point it out to me ?
Attached from vinyl engine pdf

Last edited:
I was looking at yamaha A-1 integrated, and paying particular attention to the phono MC section.
It seems that the MM and MC phono amplifer uses a common circuit, only the MC seem to to have signal amplifier (?), instead of using the traditional step up transformer.
Just wondering what are the pro and cons using this method ?
Pro: works better, cheaper
Con: much harder to design than just slapping in a transformer
Another thing is in vintage knob, it claim the input impedance of MC is 10 ohms, but I could not locate where the input impedance (is it R401(orR301), but that is 82K or did it base on the reflected amplification value wild guess 0.6u:82K => 1:136K ). So would someone please kindly point it out to me ?
Attached from vinyl engine pdf
View attachment 581903
The diagram is too small to read. If you can post a legible version I may be able to answer the question.
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