@Mark
Some time ago (3-4 years to back), i just try to mix CD-AUDIO output (digital, from back side of cd-drive, not from front side where is a headphones output). I just mix output from cd, and from paula and for me, it was works, but as said your first link i was have "increased distortion in the sound." In other words, cd-audio output was have very low valume level. But, it was works. After this tests, i just take off this, becouse volume level was suck, and just do not remember it.. But after your post, i read your link, and must say, that 'resistors' must help (im sure on 85%). I will try this today or tommorow. Maybe will need not 10k resistors, but with voltmeter it is no problem.
