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Apollo Solo Multi-Unit Cascading

Important Notes:

  • All information in this article also applies to Arrow.
  • Only one Apollo Solo can be used in a multi-unit system. Apollo Solo cannot be used with Apollo Twin or Apollo x4.

About Expanded UAD Systems

Apollo Solo can be combined with Apollo Thunderbolt interfaces and UAD-2 DSP Accelerators to increase I/O channel counts and UAD DSP processing as your system needs grow. 

Up to four Universal Audio Thunderbolt audio interfaces (i.e., one Apollo Solo and up to three Apollo Thunderbolt rack-mount interfaces) can be connected and used together as a single consolidated multi-unit I/O and DSP processing system. UAD-2 DSP Accelerators can also be added for additional UAD DSP processing within a DAW. 

Apollo Solo Multi-Unit Cascading: UAD Device Compatibility

  • Click here for UAD device compatibility with Apollo Solo when multi-unit cascading.

Multi-Unit Cascading: Operation Notes

For complete operating instructions, see the Apollo Solo Software Manual.

  • Monitor Designation: To facilitate the mix bus integration within Console, one Apollo unit must be designated as the monitor (master) unit in the Hardware panel within the Console Settings window. All other Apollo units are expander (slave) units.
  • Monitor Outputs: The monitor speaker system (or systems, with ALT monitoring enabled) must be connected to the outputs of the monitor unit only.

    Note: The monitor outputs of expander units are available as line outputs in the Core Audio panel (within the Console Settings window) and are not affected by the monitor level.

  • Monitor Knobs: The hardware monitor knob on the front panel of expander units, and their surrounding LED level rings, are disabled. To adjust the monitor output level, use the front panel monitor knob on the monitor unit or the monitor level control in Console.
  • Cue Outputs: The cue mix buses can be routed to hardware outputs on the monitor unit only.

    Exception: Cue mixes can be routed to the headphone outputs of any monitor or expander unit. 

  • Flex Routing: Inputs in Console can be directly routed (via Output Route menu) only to hardware outputs of the same unit.

Multi-Unit Cascading: Clocking

Note: All Apollo multi-unit clocking is carried via Thunderbolt. All connected Apollo units always clock (slave) from the monitor unit, regardless of whether the monitor unit is set to internal or external clock.

  • Internal clocking:
    • When multiple units are connected via Thunderbolt, all Apollo system clocking and clock settings are automatically configured by Apollo’s device drivers.
    • The monitor unit's clock setting must remain on INTERNAL unless specifically clocking to an external (non-Apollo) device.
    • When the monitor unit’s clock source is set to INTERNAL, “EXT” will illuminate on the front panel hardware of the expander units.
  • External clocking:
    • Important: When slaving to an external (non-Apollo) clock, connect the external clock source to the monitor unit only.
    • All expander units are automatically configured to use the external clock when Apollo’s clock setting is EXTERNAL.
    • When the monitor unit’s clock source is set to EXTERNAL, “EXT” will illuminate on the front panel of both the monitor unit and all expander units.