I'm hoping an ADC expert can help me here:
One of my phono amps (an old EAR 834P) has quite high fixed gain of about 49 dB I think (this for MM) which leads to an output level similar to a CD player. I recently got a new cartridge with a higher output level than my old cartridge (3.5 mV vs 2.5 mV) and noticed distortion particularly audible on loud solo piano notes, but only when using the ADC on my receiver - when I switch the receiver to pure direct analogue only mode, the distortion goes away.
It's definitely related to level, if I put my headphone amp (which has a variable line out) inbetween the phono amp and my receiver and attenuate the signal slightly, the problem also goes away with the amp in ADC mode.
So it seems that somehow the amp's ADC is overloading, which is strange as the analogue input level would surely be below the amp's specified limit of "2.3 V or more".
Could my old EAR 834P (tubes and all!) be chucking out some ultrasonics which are confusing the amp's ADC? Or what else could be happening?
Thanks.
One of my phono amps (an old EAR 834P) has quite high fixed gain of about 49 dB I think (this for MM) which leads to an output level similar to a CD player. I recently got a new cartridge with a higher output level than my old cartridge (3.5 mV vs 2.5 mV) and noticed distortion particularly audible on loud solo piano notes, but only when using the ADC on my receiver - when I switch the receiver to pure direct analogue only mode, the distortion goes away.
It's definitely related to level, if I put my headphone amp (which has a variable line out) inbetween the phono amp and my receiver and attenuate the signal slightly, the problem also goes away with the amp in ADC mode.
So it seems that somehow the amp's ADC is overloading, which is strange as the analogue input level would surely be below the amp's specified limit of "2.3 V or more".
Could my old EAR 834P (tubes and all!) be chucking out some ultrasonics which are confusing the amp's ADC? Or what else could be happening?
Thanks.
