Samson MPL 1640 manual Using Bus 3/4

In addition to the Main Mix stereo output, the MPL 1640 provides two indepen- dent bus outputs (Bus 3/4).* A “bus” is simply a pathway through which a signal can be routed. The provision of these secondary outputs makes it possible for you to create two mixes simultaneously, so that some channels send signal to the Main Mix output jacks (via the Main L/R faders) while other channels send signal to the Bus 3 and 4 output jacks.**

For example, when using the MPL 1640 with a two-track digital or analog tape recorder, you might want to connect the Main Mix outputs to the tape inputs while connecting the Bus 3/4 outputs to the inputs of a stereo power amplifier. If you then connect the tape outputs to two channels routed to Bus 3/4 (by pressing in their Bus switches), you can then use the Main L/R faders to control the signal level going to tape while using the Bus 3/4 level knob to control the playback volume (you’ll want to set the tape recorder to monitor input signal while recording). See the “Applications” section on page 24 of this manual for more information.

If no equipment is connected to the rear panel Bus 3/4 output jacks, you can use the MPL 1640 Bus switches to mute particular channels (that is, remove them temporarily from the overall mix without having to change their fader position). To do this, all you have to do is press in that channel’s Bus switch; when you do so, the signal will be rerouted to the Bus 3/4 output jacks (which are not connected to anything) and will be removed from the Main Mix you hear. To restore the signal (that is, unmute it), all you have to do is press that channel’s Bus switch again—since its fader hasn’t been moved, the sound will come back at the same level as before.

*When only two outputs are required, the Main Mix outputs are preferable to the Bus 3/4 outputs since they provide electronically balanced jacks.

**A channel cannot be routed to both the Main Mix and Bus 3/4 output jacks simultaneously. Note also that the MPL 1640 Aux returns are hardwired to the Main Mix outputs; there is no provision for routing their signal to the Bus 3/4 outputs.

Using Bus 3/4

MAIN MIX OUT

(BALANCED 600Ω + 4dB)

L

R

3L - 4R(UNBAL.2KΩ +4dB)

0

−∞ +15

3 - 4

LEVEL

BUS

L / R MUTE 3 / 4

17