Sony STR-DA1000ES Technical Background page 28

For efficient space utilization and minimum point-to-point wiring, the
STR-DA9000ES uses a motherboard/daughterboard circuit topology.
Silver Cascade Design (STR-DA3000ES and up)
In addition to their remarkable technology, these receivers inaugurate a
new faceplate design exclusive to the Sony ES Series. The "cascade" design
sets the primary front panel controls at an angle, so that you can use them
without uncomfortable bending and stooping to identify each control. The silver
colored faceplate is made of brushed aluminum and fits in beautifully with
conventional audio components. But the design really comes into its own when
the receivers are combined with other silver cascade components, such as the
SCD-XA9000ES Super Audio CD player or the DVP-NC555ES DVD/CD/SA-CD
5-disc changer.
The DVP-NC555ES 5-disc DVD/CD/SA-CD changer shows how the
Silver Cascade design extends to source components.
ES Receivers V3.0 Page 28