Hello Ed! The main difference with the "1.22" version appears to be a few additional functions on the display, the audio performance seems unaffected
If you are getting clipping when using EMPHASIS try reducing the gain by a couple of dB as you will still get better resolution with your DAC
The other suggestion I would make is to try the 518 in TYPE 1 mode as well. Also in TYPE 1 there is a BYPASS mode in addition to the other DSP modes so that should help in your comparisons, although of course you will have to place your pre-amp back in circuit
Regards, Richard.