PPM608

45

46

48

42

 

 

 

49

43

47

 

50

44

 

 

 

fiers, so only loudspeakers connected to the rear panel speaker-level outputs [3] will be affected.

44. POWER AMP LIMITER LEDs

These independent LEDs turn on when power amplifier channel A or B is being overloaded internally and its internal automatic limiter (which is always in the signal path) is actively working. The LED will pulse in time with how much the limiter is being used in the signal path.

If the Limiter LEDs come on and

stay on for more than a second or two, it means the power supply

has overheated and the limiter is holding the amp signal down to 1/4 power until the power supply cools down enough to release the limiter. If this happens, check there is good ventilation around the mixer, and that you are not cranking it too much. Also make sure that your speakers are OK, and are not less than 4 ohms impedance.

42. PHANTOM SWITCH

Press in this switch to add phantom power to all the XLR microphone inputs of the mixer. This lets the mixer send low-current DC voltage to the mic’s electronics through the same wires that carry audio. The LED will turn on as a reminder that phantom power is engaged.

Most modern professional condenser mics are equipped for phantom power. Semi-pro condenser mics often have batteries to accomplish the same thing. “Phantom” owes its name to an ability to be “unseen” by dynamic mics (Shure SM57/SM58, for instance), which don’t need external power and aren’t affected by it anyway.

Never plug single-ended (unbalanced) micro­

phones, or ribbon mics into the mic input

jacks if phantom power is on.

Do not plug instrument outputs into the mic

input jacks with phantom power on unless you know for certain it is safe to do so.

43. PRECISION PASSIVE EQ

If you are using Mackie passive speakers such as the C200, C300z, S408, S215, and S225, then press this switch for enhanced clarity and low-frequency response. If you are not using Mackie speakers, then press it anyway and listen for an improvement. The passive EQ circuit is added just before the internal power ampli-

22 PPM608

Stereo Effects Processor

The Mackie Running-Man 32-bit internal effects processor is a mono-in, stereo-out effects processor, with 24 presets. It is fed by adjusting the FX/mon 2 control [22] on each channel.

The output from the processor can be added to the main mix or monitor 1 mix by adjusting the FX to main [33] and FX to mon 1 [38] controls.

This processor is also doing the calculations that hold together the very fabric of the space-time continuum (or at least the lunch-time portion of it).

45. FX/MON 2 SEND MASTER

Use this knob to control the level of the signals going into the internal effects processor. Adjust it carefully, with your inner magical eye on the adjacent SIG/OL LED [46] to prevent overloading the effects processor.

It also affects the level going out of the FX/mon 2 line level output [15], and the internal power amplifier if it is playing monitor 2.

46. SIG/OL LED

This dual-LED illuminates in green when the signal level going into the effects processor is in a good operating range (SIG). It illuminates in red when the effects processor is being overloaded with too strong a signal (OL). Turn down the level [45] if it is.