Hi, idgmusic64,
When I was experimenting with different gain and loading options with the JD9 I found that using a lower impedance setting (higher MC cartridge damping effect) would shift the tonal balance towards the bass frequencies. So the 70 Ohm setting may be preferable in your system. However, loading up the cartridge too much can roll off the high end, so the 100 Ohm setting may be what you need.
As for gain and volume settings, a high output MC cartridge pretty much requires using the "LOW OUT" connection because the JD9 has such high gain to begin with. Are you using the +/- 35dB gain setting or the -55dB setting? If you're already at -35dB and still using the lower end of your volume control you could try using in-line resistors to further reduce the output voltage of the JD9 to better match your integrated amp. That way you'd have much more range in the volume control.
You could try something like -20dB Rothwell attenuators between the JD9 and your integrated amp. The attenuators plug into the RCA inputs on your integrated and you plug your JD9 cables into the attentuators. I use Rothwell attenuators for a CD player and a streamer/DAC to get a better voltage match with my integrated amp and they work really well in my experience.
http://www.rothwellaudioproducts.co.uk/html/attenuators.html
https://rothwellaudio.16.ekm.shop/in-line-attenuators-2-p.asp
I don't know if a -10dB Rothwell or -12dB Harrison attenuator would reduce the voltage enough but you could give that a try first. I ended up with -10dB attenuators that I don't use because they weren't the right values for my integrated amp but your Sphinx 3 is less sensitive (higher input voltage) than my integrated so the lower value resistors might work well for you.
Tom
When I was experimenting with different gain and loading options with the JD9 I found that using a lower impedance setting (higher MC cartridge damping effect) would shift the tonal balance towards the bass frequencies. So the 70 Ohm setting may be preferable in your system. However, loading up the cartridge too much can roll off the high end, so the 100 Ohm setting may be what you need.
As for gain and volume settings, a high output MC cartridge pretty much requires using the "LOW OUT" connection because the JD9 has such high gain to begin with. Are you using the +/- 35dB gain setting or the -55dB setting? If you're already at -35dB and still using the lower end of your volume control you could try using in-line resistors to further reduce the output voltage of the JD9 to better match your integrated amp. That way you'd have much more range in the volume control.
You could try something like -20dB Rothwell attenuators between the JD9 and your integrated amp. The attenuators plug into the RCA inputs on your integrated and you plug your JD9 cables into the attentuators. I use Rothwell attenuators for a CD player and a streamer/DAC to get a better voltage match with my integrated amp and they work really well in my experience.
http://www.rothwellaudioproducts.co.uk/html/attenuators.html
https://rothwellaudio.16.ekm.shop/in-line-attenuators-2-p.asp
I don't know if a -10dB Rothwell or -12dB Harrison attenuator would reduce the voltage enough but you could give that a try first. I ended up with -10dB attenuators that I don't use because they weren't the right values for my integrated amp but your Sphinx 3 is less sensitive (higher input voltage) than my integrated so the lower value resistors might work well for you.
Tom