MBI 24 Owners Group
MA01

MA01 Aux master channel (images)

Comes in two flavours: MA01P and MA01B. The main difference is that the P version is fitted with controls for 4 mono aux outputs (although aux 3 and 4 can be used as a stereo pair), while the B version assumes that aux 3 and 4 will always be used as a stereo pair.


Connections

  • SK1 - Meter outputs for aux 1 (tip) and aux 2 (ring)
  • SK2 - Meter output for aux 3 (tip) and aux 4 (ring)
  • Aux 1 - Balanced output for aux 1 (mono)
  • Aux 2 - Balanced output for aux 2 (mono)
  • Aux 3 - Balanced output for aux 3 (left)
  • Aux 4 - Balanced output for aux 4 (right)
  • SK3 - 9 way sub-D - Provides access to volt free loops closed for local mute and distant mute (two for each). Both sets are closed when mute
    • Pins 1-2 Distant mute
    • Pins 3-4 Distant mute
    • Pins 6-7 Local mute
    • Pins 8-9 Local mute
  • Optional unbalanced insertion points taken for the 4 auxes between V1-V19, V3-V21, V5-V23, and V7-V25
    Note that there are no sockets fitted to this example
    Note modifications made to this board, V1 is not connected to V19 and V3 is not connected to V21, thus disabling aux 3 and 4

Jumpers and settings

  • P1 - sets the behaviour of RV3 and RV4 (not fitted in the B version), so that double ganged RV3 can control stereo pair aux 3/4 making RV4 redundant
  • P2 - sets the behaviour of S4 (not fitted in the B version), so that S3 engages AFL 3 and 4 together for operation of aux 3 and 4 as a stereo pair

Controls


MA01B

Three master output gain pots, one each for aux 1 (RV1), aux 2 (RV2), and aux 3/4 (double ganged RV3a/b). Also three latched switches (S1, S2, and S3) for AFL (Aux Feed Listen), which allows monitoring of the selected aux bus via the PFL bus.


MA01P

Four master output gain pots, one each for aux 1 (RV1), aux 2 (RV2), aux 3 (double ganged RV3a/b), and aux 4 (RV4). Also four latched switches (S1, S2, S3, and S4) for AFL (Aux Feed Listen), which allows monitoring of the selected aux bus via the PFL bus.

When aux 3/4 are used as a stereo pair, set by jumpers P1 (sets the behaviour of RV3 and RV4) and P2 (sets the behaviour of S3 and S4), the aux 4 pot (RV4) and the AFL 4 switch (S4) become redundant, as the aux 3 pot (RV3) is double ganged.