Excellent surround sound preamp processor with many digital and analog inputs. Dolby Digital, DTS, Dolby Pro Logic II surround modes built in. Can be used as an excellent stereo preamp as well! If HDMI switching is required, this unit can be used with the Meridian HD621 or UHD 722 (4K) for convenient HDMI audio and video switching. (Meridian doesn't build it in due to sound quality concerns) This piece was sent back to Meridian a year ago for the new digital power supply, a very significant sonic upgrade! One of the best surround processors ever made according to many different reviews in respected magazines like Home Theater and Stereophile. Now, at a fraction of the original retail! Paypal adds 3%.