Isn't the key difference that the 1070 was an entirely new design unique to Outlaw, while the 990 is an upgraded clone of an already existing product? Obviously, there is a lot more that can go wrong in the first case.

And if we move to speculation, what do you think Outlaw would do if the 1070 actually sounds better than the 990 (as a pre-pro)?
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Living Room 24x18 open 1/2 flight up to a raised dining room/hall 24x12
Outlaw 976 pre-pro running 5.1 system
Outlaw 750 for Artison Masterpiece LCR and 2 NHT SuperZeros rears
Velodyne Servo FX-1200
LG OLED65C8PUA via HDMI2 to/from 976 HDMI ARC
Roku Ultra
Samsung BD-D5500 BluRay
Amazon FireStick 4K to 976 Aux HDMI input for Amazon Music Ultra