I purchased a 3B in 1989 if memory serves me right. There were previous versions so its hard to say which version you own...
Specs were:
Distortion:
Harmonic - less than 0.01% from 20 to 20kHz at rated power
IM - less than 0.01% from 10 milli-watts to full rated power
Noise - 100db below full output
Crosstalk - Below noise 20 to 20kHz
Slew rate - greater than 60 volts per microsecond
Power bandwidth - less than 1 Hz to over 100 kHz
Damping factor - over 500 at 20 Hz, ref. 8 ohms
Power - 100 w/ch @ 8 ohms, 200 w/ch @ 4 ohms
Specs were:
Distortion:
Harmonic - less than 0.01% from 20 to 20kHz at rated power
IM - less than 0.01% from 10 milli-watts to full rated power
Noise - 100db below full output
Crosstalk - Below noise 20 to 20kHz
Slew rate - greater than 60 volts per microsecond
Power bandwidth - less than 1 Hz to over 100 kHz
Damping factor - over 500 at 20 Hz, ref. 8 ohms
Power - 100 w/ch @ 8 ohms, 200 w/ch @ 4 ohms