Rane MQ 15, MQ30 User Manual

OPERATING / SERVICE MANUAL

GRAPHIC EQUALIZERS

MQ 15/30

QUICK START

Reading this section is a lot like eating spinach. Once you’re through, you can have dessert. So read this spinach, then

devour your MQ dessert.

Hook-up is intuitive. Just follow the silkscreened instructions on the rear of the unit. All three inputs are wired in
parallel (they do not sum); and all three outputs are wired in parallel. Use any ONE input and any or all outputs. Using
the MQ 15/MQ 30 in an Insert Loop of a mixer is extremely easy. Simply connect them together using a single stereo
cable (1/4" TRS) between the mixer’s Insert Loop and the PATCH I/O jack. This jack is wired for the tip=send,
ring=return convention used by many mixer manufacturers. CAUTION: USE EITHER THE PATCH I/O OR ANY OF
THE INPUT AND OUTPUT CONNECTORS — DO NOT USE BOTH AT THE SAME TIME.

Anyone familiar with other graphic equalizers finds the MQ 15/MQ 30 just as familiar. One word of caution: the
boost/cut RANGE switch drastically changes the impact of a given filter. BE CAREFUL.

Setting the IN and OUT GAIN controls to the same physical positions gives unity gain through the equalizer. That is,
moving both slider handles together (keeping them aligned) always maintains overall unity gain from input to output.
Many strange gain structure conditions may be handled with these controls. FOR BEST NOISE PERFORMANCE
ALWAYS POSITION BOTH CONTROLS AS FAR TOWARD THE TOP OF. THE UNIT AS POSSIBLE WITHOUT
LIGHTING THE OL INDICATORS. See the Operating Instructions on the back page for more information, Most
applications require only a few dB of boost or cut. Start with the RANGE switch in the 6dB position and increase to

12dB only if necessary. Setting curves is as easy as it is on all Rane graphics thanks to our unique interpolating constant-

Q circuitry. For more information on setting up your curves correctly, again, see the back page.

NEVER CONNECT ANYTHING EXCEPT AN APPROVED RANE POWER SUPPLY TO THE RED THING

THAT LOOKS LIKE A TELEPHONE JACK ON THE REAR OF THE UNIT. This is an AC input and requires

special attention if you do not have a power supply EXACTLY like the one originally packed with your unit. See the full
explanation of the power supply requirements elsewhere in this manual.

SYSTEM CONNECTION

When first connecting the MQ 15 to other components, LEAVE THE POWER SUPPLY FOR LAST. This gives you a

chance to make mistakes and correct them without damaging your fragile speakers, ears and nerves.

INPUTS. All three inputs are wired in parallel and are actively balanced (true instrumentation amplifiers). Each works

equally well. Choose strictly from a favorite hardware point-of-view, there will be no performance trade-offs. The wiring
convention adheres to American, British and International standards of pin 2 “+”, or tip being hot, pin 3 “–”, or ring being return,
and pin 1, COMMON GND, or sleeve being signal ground. Unbalanced operation involves using only pin 2 “+”, or tip as
signal and pin 1 COMMON GND, or sleeve as ground. It is not necessary to short any terminals or pins to any others. Due
to the true instrumentation nature of the inputs, there is no gain reduction if pin 3, or –,
shorted, it won’t hurt anything either. Use pin 1, the shell, or the COMMON GND point on the barrier strip for shield
ground. (See Rane Note 110 for further information).

OUTPUTS. The outputs mimic the inputs. True balanced output interconnection only requires the use of pin 2 “+”, or tip,

and pin 3 “–”, or ring for signal transmission. It does not require pin 1, or signal ground. The signal exists differentially
between the two balanced leads; ground is not involved. Ground is used only for shielding. Again, have a look at Rane Note

110 for more detail.

is left open; however, if pin 3 gets

(continued on next page)...

FRONT PANEL DESCRIPTION

1. MASTER OVERLOAD INDICATOR. This red OL LED monitors the input, output and all filter stages for excessive

signal levels. It lights whenever these levels exceed 4dB below clipping. Occasional flickering is normal; however, it
should not be allowed to light steadily.

2. OVERALL BYPASS SWITCH & INDICATOR. This pushbutton switch activates the “hard-wire” bypass function.

When engaged (red BYPASS LED on), all three pins of the input connectors directly connect to the same pins on the
output connectors (hard-wired). Engaging this switch converts the MQ 15/MQ 30 into a relatively expensive patch cord,
but one with pretty lights.

3. INPUT AND OUTPUT GAIN CONTROLS. These slide controls set the relative IN and OUT gain structures. The range

of each control is ±12dB; however, note they are labelled opposite to each other, i.e., the top of the IN control reads
+12dB while the top of the OUT controls reads -12dB. Configured this way, whenever they are held and moved together
the overall gain through the MQ 15/MQ 30 stays at unity. Positioning these controls (together) as far toward the top of
the panel as possible (without lighting the OL indicator) yields the best signal-to-noise performance.

4. FILTER LEVEL CONTROLS. These slide controls set the individual levels of the interpolating constant-Q filters. Their

range is selectable between 6dB (use bottom or right-hand scale) and 12dB (use top or left-hand scale). The grounded
center-detent design of these sliders ensures all filters are off when positioned to their centers.

5. FILTER RANGE SWITCH. Sets the overall range of all sliders between 6dB and 12dB.

6. POWER INDICATOR. This yellow LED lights any time remote power is supplied from either a RS 1 single

power supply or a RAP 10 multiple power supply. Note that this indicator is electrical, not political.

SYSTEM CONNECTION (continued)

EXPANDING. Expanding and/or daisychaining the inputs and outputs normally uses the 1/4" jacks. Three parallel input

connectors allows driving a second signal processor or amplifier without special cabling.

PATCH I/O. The PATCH I/O (Input/Output) jack makes connection to mixer Effects Loop insert points very simple.

Just connect a shielded stereo tip-ring-sleeve (TRS) cable between the PATCH I/O jack and the TRS Effects Loop insert on
your console. (Your mixer must use the tip=send, ring=return Effects Loop wiring convention.)

SIGNAL LEVELS. The MQ 15/MQ 30 is designed for all line-level signals. Signal levels from -10dBV to +4dBu are

considered normal and within range (at least 16dB of headroom exists above these levels). Do not directly connect micro­phones into the MQ 15/MQ 30. Use a mic preamp (e.g., Rane model MS 1) first.