Rane MA 6S User manual

Manual-1
OPERATORS MANUAL MA 6S
MULTICHANNEL AMPLIFIER
QUICK START
You gots your good habits, and you gots your bad habits. A good habit is to read at least this much of the manual. A bad
habit is not to read any of this manual. Reading just this section can prevent grief worse than your worst nightmare. Grief
that's hard to get rid of—harder than a bad habit.
Be sure the amplifier is off before making any connections. Euroblocks make connecting and unconnecting the amplifier
easy. They are just like little snap-on terminal blocks.The balanced Input blocks are green, and the speaker Output blocks
are black. Driving the MA 6S from a balanced source is recommended. If you just have to drive the MA 6S Input with an
unbalanced source, we recommend using cable that has two conductors with a shield. Connect the sources + or “hot” to the
MA 6S’s +, the – or ground to the MA 6S’s –, and connect the shield to the MA 6S’s SHLD. Do not connect the shield at
the source end. Keep your input cable lengths as short as possible. See RaneNote 110, “Sound System Interconnection” for
more information regarding this issue. Speaker loads should be no less than four ohms per output. If you are running
multiple speakers per Channel in series or parallel, check your impedances, and consider the KTM 6 Transformer Kit as an
option. If you do use 100V, 70.7V or 25V output transformers, we recommend engaging the 80 Hz High Pass Filter jumpers
as described on page Manual-4.
If you are running six separate Channels (unbridged), be sure all the BRIDGED switches on the rear panel are de-
pressed. If you are running any Channels bridged, you are obviously a power user and we highly recommend you read
further into the manual regarding this issue.
With Input and Output connections completed, be sure all front panel LEVEL controls are all the way counterclock-
wise. Now flip the POWER switch and after hearing the relays click in after a second, notice that the READY lights come
on. Slowly turn up each Channel's LEVEL control to the desired gain and if all is well you should hear something pleasant.
If not, re-check connections, put on a better CD, and read more of the manual.
WEAR PARTS: This product contains no wear parts.

Manual-2
FRONT PANEL DESCRIPTION
햲POWER switch: Obediently turns the MA 6S on and off every time you poke it with your finger (or other suitable object).
All six Channels have delayed turn-on/instant turn-off relays to eliminate any switching transients.
햳THERMAL Overload indicator: Lights red if the MA 6S becomes too hot, indicating that power has been removed from
all six Channels. Be sure to check the fan filter and actual speaker impedances if this lights up.
햴POWER indicator: Lights yellow whenever the MA 6S POWER switch (햲) is turned on.
햵READY indicators: Light green whenever the mute relay is passing the signal through to the speaker. Normal operation is
the on status.
햶SOA LIMIT indicators: Light red whenever a Channel leaves the Safe Operating Area (SOA). This means the amplifier
turned down the Input level quickly and automatically, avoiding over-dissapation. Input signals 30 dB over a safe limit will
cause the READY indicator and mute relay to turn off until the amplifier has been turned off and the problem corrected.
Normal operation is the off status.
햷CLIP LIMIT indicators: Light red whenever a Channel’s Output cannot follow its Input. The amplifier has turned down
the Input level quickly and automatically, avoiding audible distortion. Normal operation is the off status.
햸CHANNEL LEVEL controls: Determine the Input sensitivity of each respective Amplifier Channel. At its full clockwise
position, an Input signal of 0 dBu (.775 vrms) drives the Amplifier to full power. As the controls are rotated counterclock-
wise, more Input signal level will be needed to achieve full power. If the calibrations appear backwards with respect to most
level controls, it is because they are Input sensitivity markings, not attenuation indications.
NOTE: To install the MA 6S security covers, which have been supplied with the Amplifier in the form of six small black plastic
caps, set the six LEVEL controls to the desired position and then pull the knobs off. Insert the plastic covers in the now
vacant holes. You may then sleep soundly knowing that your Amplifier installation cannot be mindlessly violated.

Manual-3
REAR PANEL DESCRIPTION
햲INPUTS: These are balanced Euroblock connectors. Cable should include two wires with shield. Euroblocks accept up to
12 AWG wire. The shield may be attached to either chassis or signal ground. For unbalanced sources consult the included
RaneNote, “Sound System Interconnection.”
햳OUTPUTS: Connect the speaker(s) to each of the six Channels by means of the Euroblock connectors with 18 to 12 AWG
wire (See 햴for Bridged operation).
햴NORMAL/BRIDGED switch: With the switch in the out position and the red Bridged indicator on, the MA 6S is operating
in BRIDGED mode. The MA 6S utilizes the BRIDGE switch to make internal connections between each pair of Channels:
1&2, 3&4, and 5&6. Whenever a signal is connected to an odd numbered Channel (say Channel 1), the next even-numbered
Channel is driven inverted when the BRIDGE switch is activated. Connect Inputs to odd Amplifier Channels only (1,3,5),
and connect speakers to the “+” terminals of each Channel pair as shown on the MA 6S chassis silk-screen. When the
BRIDGE switch is inactive, the internal connection is defeated and both Channels operate independently.
햵AC line cord: Plug this into a grounded l20 VAC AC outlet (or 230 VAC if the MA 6S is internally wired for 230 V
operation).
햶Line FUSE: For 120 volt operation, use only a 15 amp 250 volt Fast-blow (or Normal blow—not Slow blow) fuse, 1.25"
long, such as Buss ABC-15 or equivalent. For 230 volt operation use Buss AGC-8 or equivalent.
햷Fan filter: This washable filter may easily be removed for periodic cleaning by gently pulling on the black plastic housing
and then lifting it away–perform this feat with the fan off, of course. Once the filter is removed, rinse it under hot tap water;
use dish soap to cut through particularly stubborn “tav sludge.” The MA 6S draws a tremendous amount of air to ensure
proper cooling and resultant long term reliability. Check and clean the filter as often as necessary, especially if the THER-
MAL overload indicator ever comes on.
IMPORTANT: Keep this filter clean to ensure proper cooling and reliability of the MA 6S. Never remove the filter with the
unit plugged in.

Manual-4
MA 6S CONNECTIONS
Direct, Biamp, and Bridged Wiring

Manual-5
The MA 6S will drive an active two-way stereo system when wired as shown. The high frequency drivers run direct from
Channels 5 and 6. The low frequency drivers, requiring much more power, are run from two bridged pairs: Channels 1 and 2
are bridged to one woofer and Channels 3 and 4 are bridged to the second woofer.
CAUTION: 8 ohms is the lowest impedance that can be driven by the MA 6S in BRIDGED mode. If there are two woofers in
each bass cabinet, be sure they are wired in series if they have an individual impedance of less than 16 ohms each.
WIRING NOTE: Whenever connecting any device to the MA 6S Inputs, be aware of signal grounding paths. Connect the
shield to MA 6S Chassis Ground for proper cable shielding. Some installations may permit ground connection to Signal
Ground on the Euroblock, but the best ground is directly to the Chassis.
In addition, since the AC 22 does not get it's ground through the line cord, its chassis should be grounded through either the
rack rails or a jumper wire connecting the chassis' of both units. See the included RaneNote, “Sound System Interconnection”
for a full explanation and proper wiring techniques.
Stereo Biamped Wiring

Manual-6
©Rane Corporation 10802 47th Ave. W., Mukilteo WA 98275-5098 TEL [phone] FAX [phone] WEB http://www.rane.com
OPERATION
Voltage Controlled Attenuators
The voltage controlled attenuators (VCAs) in the MA 6S
allow a significant increase in usable volume levels without
excessive clipping or interference from conventional distor-
tion causing muting circuits. The VCAs do not affect dynamic
response, distortion or noise levels of any material within the
rated output specifications of the amplifier. They simply
monitor the difference between Input and Output signals, and
the power dissipated in the output devices. In the event of
clipping or excessive dissipation in the output devices, the
VCAs “jump in” (out of hiding, as it were) and turn down the
Input level to correct the overdrive condition.
This means that whenever a CLIP LED flashes, a musical
peak has been quickly turned down to avoid excessive
clipping. This allows you to run the amplifier at a higher
continuous level, typically about 4 dB SPL higher than
without VCAs. And that 4 dB of increased SPL is the equiva-
lent of a 250 watt amplifier without VCAs. If an SOA LED
flashes, the Input level has been quickly turned down to
prevent over-dissipation in the output devices due to excess
phase shift or abnormally low impedances which may occur
at some frequencies. This protection occurs without distorting
or interrupting the musical program.
Keep an eye on the LEDs on the MA 6S front panel.
Occasional flashing of the CLIP LEDs and/or occasional
flashing of the SOA LEDs means you are getting the most
SPL out of the amplifier. Continual lighting of either LED
indicates excessive input overdrive, or too low impedance of
load. If the green READY LED goes off, a load has been
encountered that could not be corrected by the VCAs, or the
amplifier has offset. If this occurs, the amplifier must be
turned off and the problem corrected before the Channel can
be operated. If the READY LED will not light with the load
disconnected, then an internal fault has occurred and the
amplifier is in need of repair.
Adapting the MA 6S to Your Changing Needs
With six Channels to choose from and built-in Bridging,
there are a number of different combinations available to suit
your present and growing needs. The nice thing about the
MA 6S is that you can re-configure it instead of losing money
on an obsolete, used piece of gear you no longer need.
Basically, you can start out with 6 Channels at 100 watts
or three Channels at 300 watts. When the time comes, you can
step up to six Channels at 300 watts by obtaining another
MA 6S and keeping the original. Upgrading to biamped
monitors or tri-amped mains becomes easy as well, by simply
adding a second MA 6S, both taking up only 10.5" rack
space.
About the MA 6S and Circuit Breakers...
The MA6S will easily deliver over 900 watts of audio
power, which requires as much as 15 amps of current from the
AC outlet. 15 amps is not an uncommon value for household
and some institutional circuitbreakers, though
20 amp versions are becoming more common. The bottom
line is that the MA 6S is capable of tripping a 15 amp circuit
breaker under normal operation. An amp that delivers a lot of
power, drinks a lot of power to do so.
It is not likely that you will trip a breaker, but it is wise to
be aware of the possibility so you don’t panic if it happens.
INTERNAL JUMPERS
Each amplifier card contains a jumper block that gives the
option of inserting an 80 Hz High Pass Filter into the Input
signal. This is recommended in 70 or 100 volt systems when
excessive bass can saturate the transformers, reduce the
output, and possible blow a fuse at high output levels.
The MA 6S is shipped with these jumpers in the out
position (filters defeated). Moving this jumper to the in
position activates the filter.
CAUTION: WAIT ABOUT 15 MINUTES AFTER THE
AMPLIFIER HAS BEEN POWERED DOWN BEFORE
BEGINNING DISASSEMBLY, TO ALLOW THE
POWER SUPPLY CAPACITORS TO DISCHARGE.
1. Remove the bottom cover: 4 each #6 x 3/8" phillips
screws on the bottom of the side rails and 12 each #6 x 1/4"
phillips screws on the bottom cover.
2. 80 Hz High Pass Internal Jumpers: To access the jumper
on each amplifier card, locate J2 (LOW FILTER). The
MA 6S is shipped with these jumpers in the OUT position
(filters defeated). Moving this jumper to the IN position
activates the filter.
103088
In the event that 80 Hz is not a high enough cutoff
frequency, values may be changed to replace 3 resistors on
each amplifier card. This operation requires dissasembly and
soldering as outlined in the MA 6S SERVICE INFORMA-
TION section, and should only be performed by qualified
service personnel.
V