Help--SACD volume too low

I have a Lexicon mc-12 and a Sony NS500V player. When playing SACD (2 ch or 5.1) and using the 5.1 ch inputs on the Lexicon, the sound comes thru but with a low volume. This occurs when using either the analog by-pass or the internal processing of the Lexicon. The connections and set ups are per the manuals and the cables are ok.All other formats play fine. In contrast, connecting my DVD-audio player in a similar way, the volume is plentiful. To add more confusion, I connected the Sony (2 ch) to the Lexicon stereo analog in and the volume is plentiful. I also connected the Sony (2 ch) to another pre-amp and volume is plentiful. Can anyone explain why the DVD-audio plays at loud volumes and the SACD doesn't? Any ideas will be appreciated.