Ashly MX-508 User manual

MX-508
Stereo
Microphone/Line
Mixer
Operating Manual
ASHLY AUDIO INC.
847 Holt Road Webster, NY 14580-9103 Phone: [phone]
Toll-Free: [phone] Fax: [phone] Internet: http://www.ashly.com/

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Operating Manual -MX-508 Stereo Microphone/Line Mixer
Table Of Contents
1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 UNPACKING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3 AC POWER REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4 CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-5
5 CONNECTIONS AND CABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-7
6 TYPICAL APPLICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
6.1 Small Sound Reinforcement System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
6.2 Meeting Room, Board Room, Church, etc. Using Remote Control . . . . . . . . . . 8
6.3 Location Recording or Broadcast Mixing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.4 Submixer In Larger Sound System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
7 CHANGING FACTORY CONFIGURATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
7.1 Changing the Aux Pre/Post Assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
7.2 Installation of Input Transformers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8 TROUBLESHOOTING TIPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.1 No Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.2 Distorted Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.3 Excessive Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.4 Excessive Hum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
9 DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
10 SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
11 WARRANTY INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
12 SCHEMATIC DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-15

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Operating Manual - MX-508 Stereo Microphone/Line Mixer
1. INTRODUCTION
Congratulations on your purchase of an Ashly
MX-508 stereo mixer. In one compact rack-mount pack-
age we have combined features, reliability, and sonic per-
formance previously found only in larger and more
expensive mixing consoles. This second generation mixer
is similar to the MM-508, with the addition of output mute
switches on stereo outputs and double or single jack in-
sert points on all input channels.
Other features include optional plug-in isolation
transformers on all inputs, switchable +48V phantom
power, and front panel switching on each channel select-
ing between mic or line input. Three-band equalization
with a fixed frequency low and high shelf and a tunable
mid-range control provides perfect true-reciprocal equal-
ization curves. A concentric level and pan control com-
bined with a concentric pair of auxiliary sends complete
each input channel.
Ultra low-noise summing amplifiers combine the
channel signals for the main and send outputs. Two 10-
segment LED arrays monitor main or aux outputs. Stan-
dard line level outputs on 1/4" connectors, tape outputs
on RCA connectors, and transformer isolated 600 ohm out-
puts on XLR connectors are provided as standard equip-
ment. Ashly still uses professional quality 16mm metal
shaft potentiometers on all controls for greater accuracy
and long life.
2. UNPACKING
As a part of our system of quality control, every
Ashly product is carefully inspected before leaving the
factory to ensure flawless appearance. After unpacking,
please inspect for any physical damage. Save the ship-
ping carton and all packing materials , as they were care-
fully designed to reduce to minimum the possibility of
transportation damage should the unit again require pack-
ing and shipping. In the event that damage has occurred,
immediately notify your dealer so that a written claim to
cover the damages can be initiated.
The right to any claim against a public carrier
can be forfeited if the carrier is not notified promptly and
if the shipping carton and packing materials are not avail-
able for inspection by the carrier. Save all packing mate-
rials until the claim has been settled.
3. AC POWER REQUIREMENTS
The MX-508 mixer will perform normally from
93 to 125 volts AC, 50-60Hz (some export models are
wired for 240 Volts and are labeled accordingly). Use
only properly grounded AC receptacles. To reduce the
risk of ground loop hum, use a central point for system
AC power distribution. In the event of fuse failure, re-
place only with same type fuse. Power consumption is
less than 50 watts.

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Operating Manual -MX-508 Stereo Microphone/Line Mixer
4. CONTROLS
4.1 Input Level (Gain)
This control sets the operating level of the Microphone preamp and
Line Input. Best signal to noise ratio is obtained with higher gain settings. It
is therefore desirable to set the Gain control as high as possible while still
leaving enough headroom (usually 20dB) to prevent distortion.
4.2 Mic-Line Switch
This switch selects between the XLR microphone input or the 1/4"
line input jack as the signal source. It can also serve as a "channel mute"
switch when selected to the unused input.
4.3 Channel Clip Indicator
This peak sensitive indicator monitors all level critical points in the
input channel and illuminates if any of them reach levels 3 dB below clip-
ping.
4.4 Equalization
Channel EQ consists of a high shelf control at 15KHz (middle of
shelf), a sweepable mid control, and a 70Hz low shelf control. The mid
control is sweepable from 140Hz to 8KHz with a bandwidth of approximately
1 octave.
4.5 Aux Sends
These are an additional pair of level con-
trols to adjust the feed to monitors or effects units.
Aux 1 is factory preset to pre-fader, pre-EQ, while
Aux 2 is post-fader, post-EQ. Both Aux sends can
be internally switched to pre or post fader/EQ. Note:
See section on changing factory configurations.
4.6 Level and Pan
This concentric pair of controls adjusts the
level and stereo position of the channel.
4.7 Aux Master Sends
These controls adjust the overall gain of the output stages for the Aux 1 and Aux 2
outputs.
4.8 Aux Master Returns With Pan
These concentric level and pan controls adjust the returning signal from effects units
or auxiliary inputs to the Main Left and Right outputs. Return 1 is stereo and return
2 is mono. If only the right connection to return 1 is made, this return will function
as mono with pan.
4.9 Tape/CD Input and Send
This stereo level control adjusts the Tape/CD input to the Main Stereo outputs. The
outer concentric control labeled "To Aux 1" sums the left and right Tape/CD inputs
to a mono signal and applies it to the Aux 1 Master group for use with monitors or
effects. It is "pre-fader", or independent of the stereo level control.
100PanLevel
100Aux 2Aux 1
+12-12
+12-12 5K
2.5K
1.2K
630 +12-12
-60-20dB
-50
-40
0
-30
+22 -24
Clip
M
L
Ch.1
3
1
-
Input
Level
High EQ
Low EQ
Aux1
Aux2
Mid EQ
Frequency
Level
Pan
p
Mic
Line
100
100
To Aux 1
T
ape/CD In
PanReturn 2
PanReturn 1
100
100
100
(Stereo)
Aux 2 Send
Aux 1 Send
Aux Master

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Operating Manual - MX-508 Stereo Microphone/Line Mixer
4.10 Output Meters
A pair of peak
reading 10 segment LED
meters are used to indicate
output level. Green LED's
are used below 0 VU, yel-
low above 0 VU and red
LED's indicate clipping. 0
VU is equivalent to +4 dBu
(1.228Vrms). This meter
pair is switchable (with the
headphone output) to either
the Main Left and Right
outputs or the Aux 1 and 2
outputs. The red clip LED's
will illuminate if the sum-
ming amplifiers are clip-
ping even if the main output
controls are off, in which
case one or more inputs
must be turned down. Note:
The output meters are accu-
rately calibrated to the
transformerless output lev-
els, but not necessarily the
transformer-balanced out-
puts. See note on Trans-
former Balanced Outputs.
4.11 Main Output Level
These controls de-
termine the level of both
transformer balanced and
transformerless output stages for the Main Left and Right
outputs.
4.12 Main Output Mutes
These switches turn off both the transformer-bal-
anced outputs as well as the transformerless 1/4" stereo
outputs, and indicate the mute mode by lighting the red
LED near the switch. The headphone and metering func-
tions continue uninterrupted even though there is no sig-
nal on the mixer's main outputs.
4.13 Phantom Power Switch
This front panel switch enables the 48 Volt phan-
tom power supply for condenser microphones which can
use this feature. One switch controls all the inputs. If you
have a mix of condenser and dynamic microphones, the
phantom power will not affect the operation of the dy-
namic mics.
4.14 Mono Output Level
This control adjusts the level of the summed mono
output. It is completely independent of the Main Left and
Right masters.
4.15 Headphones Level
This control adjusts the level of the designated
output signal (Mains or Aux) to the headphone jack.
4.16 Meter/Phones Select
This switch selects either the Main Left/Right
outputs or theAux 1/Aux 2 outputs to the LED meters and
the headphone jack.
4.17 Headphone Output
This front panel 1/4"TRS connector feeds a stan-
dard set of stereo headphones. A selector switch that also
controls the level meter allows monitoring the main orAux
outputs.
100
1
2
3
456
7
8
9
100
1
2
3
456
7
8
9
Main
Outputs
Left Right
Clip
+6
+3
0
-3
-6
-9
-12
-15
-18
-21
VU -R--L-
MX508
Stereo
Eight Channel
Mixer
100
Headphones
Mono Output
L/R
Aux 1/Aux 2
Meter/
Phones
Select
Power
Off On
Phantom (+48V)
010
9
8
7
6
5
4
3
2
1
MuteMute
(Aux1) (Aux2)