I have listened to the 39 run directly to levinson 27 amps to SL3s. It sounds excellent. The 39 keeps the volume control in the analog domain unlike many digital processors that do the volume control in the digital domain. In the digital domain bits are cut off to control the volume and the result affects not only the volume but the quality of signal. Levinson did it right by keeping it in the analog domain. If you do not need additional inputs, run it directly. If you do need additional inputs you will probably want to upgrade your 38 to a 380S. I had a 38S and upgraded it--it is a huge difference in transparancy.
My Mark Levinson system help
I own a 335 a 38 a theta miles & a pair of martin logan sl3s. I want to buy the 39 would my system sound better running the 39 direct into the 335. Or should I keep the 38 with the 39. Email me with any input thanks lev335@earthlink.net I think the 39 direct is the way to go..