Ashly DLM-821 User manual

DLM-821
Stereo
Ducking Line/Microphone
Mixer
Operating Manual
ASHLY AUDIO INC.
847 Holt Road Webster, NY 14580-9103 Phone: [phone]
Toll-Free: [phone] Fax: [phone]
www.ashly.com

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Operating Manual - DLM-821 Stereo Ducking Line/Microphone Mixer
Table Of Contents
1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 UNPACKING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3 AC POWER REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4 SECURITY COVERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
5 CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
6 CONNECTIONS AND CABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
7 TYPICAL APPLICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.1 Small Sound Reinforcement System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.2 Church, School Or Meeting Room Sound System . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.3 Restaurant/Sports Bar System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
8 TROUBLESHOOTING TIPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
9 DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
10 SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
11 WARRANTY INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
12 SCHEMATIC DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-15

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Operating Manual - DLM-821 Stereo Ducking Line/Microphone Mixer
1. INTRODUCTION
Congratulations on your purchase of an Ashly
DLM-821 stereo ducking line level mixer. Features include
eight balanced stereo inputs for line level sources, the first
four inputs with switchable 30dB gain for low impedance
microphones. +18V phantom power and stereo/mono switch-
ing is provided for inputs 1through 4. A concentric level
and pan control for each input adjusts channel volume and
stereo position.
A ducking circuit allowsasignal on either channel
1or 2to duck (attenuate) the signal on channels 3through
8. Internally the DLM-821 can beconfigured for ch.1 pri-
ority wherebyasignal on ch. 1has priority over the signal
on ch. 2and fully attenuates channels 2through 8. Further-
more, the ducking level can beconfigured for -20dB or
-90dB, ch. 2ducking may bedisabled, and the left and right
signal ducking may bedisabled independently. Ultra low
noise summing amplifiers combine the channel signals for
the main outputs. A pair of 6-segment LED meter arrays
monitor the main output levels. Separate level controls are
provided for stereo, mono, and headphone outputs.
2. UNPACKING
Asapart 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. Savethe 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. Inthe event that damage has occurred,
immediately notify your dealer so that awritten claim to
cover the damages can beinitiated.
The right to any claim against apublic carrier
can beforfeited if the carrier is not notified promptly and
if the shipping carton and packing materials are not avail-
able for inspection bythe carrier. Saveall packing mate-
rials until the claim has been settled.
3. AC POWER REQUIREMENTS
The DLM-821 will perform normally from 98 to
125 volts AC. Use only properly grounded ACrecep-
tacles. Toreduce the risk of ground loop hum, use acen-
tral point for system ACpower distribution. The ACline
fuse is internal, and should only bechanged byaquali-
fied service technician.
4. SECURITY COVERS
For installations where it is desirable to protect
the front panel controls from tampering or accidental
misadjustment, use the Ashly security cover, which is
available in both single and double rack space sizes. In-
stallation is simple and does not require removal of the
equipment from your rack.See your Ashly dealer for
details.
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Operating Manual - DLM-821 Stereo Ducking Line/Microphone Mixer
5. CONTROLS
5.1 Ducking Enable
Pressing this switch enables asignal present on
inputs 1or 2to duck (attenuate) the signals on inputs 3
through 8. See sections 5.14 through 5.17 for internally
selecting different ducking configurations.
5.2 Channel Level and Pan
The inner knob is the individual channel volume
control which feeds achannel to the main mix.The "5"
position corresponds to unity gain. The outer knob is the
Pan control and adjusts the position of the channel in the
stereo mix.
5.3 Mute Switch
This switch on each channel will turn the chan-
nel completely off allowing the channel level to remain
at its desired setting when the input is not needed.
5.4 Mic/Line Switch
This recessed switch on the first four inputs in-
creases the channel input sensitivity by30 dB to allow
the use of low impedance microphones. The adjacent
yellow LED on indicates the switch is depressed and 30dB
of gain is added for that channel'smic input.
5.5 Output Meters
A pair of peak detecting 6-segment LED meters
are used to indicate output level. Green LED'sare used
below 0VU,yellow above0VU,and red LED'sindicate
clipping. This meter pair monitors the main stereo out-
put (0VU = +4dBu).The red clipping LED'salso moni-
tor all input channels, making it possible for these
indicators to illuminate even with the stereo output level
turned off.
5.6 Stereo Output Level and Pan
This is the main master gain which sets the oper-
ating level for the entire mixer. The "5" position corre-
sponds to unity gain. This control does not effect the
mono output level.
5.7 Stereo Output Mute
This switch entirely mutes the main stereo out-
put. The headphone and mono output are not affected.
This is particularly useful when the DLM-821 is used as
asub-mixer.
5.8 Mono and Headphone Level
The inner knob is the master gain control for the
mono output, which is the combined signal of the left
and right outputs. Ithas no effect on the stereo output.
Note: The mono output level can beselected between
mic or line level. (see sec. 5.10) The outer knob is the
level control for the front panel headphone jack.
   
 

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Operating Manual - DLM-821 Stereo Ducking Line/Microphone Mixer
5.9 Power Switch
The DLM-821 power switch is on the back panel.
When it is pressed in the front panel power LED will be-
come lit.
5.10 Mono Output Mic/Line Switch
This switch selects between a0dBu (out posi-
tion) line level or -40dBu (in position) mic level signal
feeding the Mono output connector.
5.11 Stereo/Mono Input Switches
These four pushbutton switches allow selection
between astereo or mono signal connection to input chan-
nels 1through 4respectively. Inthe Out position, stereo
left and right cables should beconnected. Inthe in posi-
tion, amono cable should beconnected to the R(Mono)
connector which then internally feeds the signal to both
left and right sides.
5.12 Phantom Power Switches
There is aphantom power switch for channels 1
and 2and aphantom power switch for channels 3and 4.
Pushing the switch in applies +18VDCto the (+) and (-)
input terminals of the twoassociated channels to power
condenser mics. The input channels should bemuted
using the On/Mute switches when switching phantom
power on or off to avoid any pop noises.
Internal PCB Jumper Options:
5.13 Ch.2Detect Enable *
Internal jumper J1allowsenabling or disabling
the ducker detector for ch. 2. (factory default is enabled)
5.14 Ducking Level *
Internal jumper J16 allowsselection between
-20dB ducking level and -90 dB ducking level. (factory
default is -20dB)
5.15 Ch.1Priority *
Internal jumper J6allowsenabling ch. 1to have
priority over ch. 2and fully attenuate channels 2-8. This
feature is useful for applying an emergency page or alarm
on channel 1and applying anormal host page input on
ch. 2. (factory default is ch.1 priority disabled)
5.16 Left and Right Ducking Enable *
Internal jumpers J14 and J15 allow the left and
right signal ducking to beenabled or disabled indepen-
dently. (factory default is left and right ducking enabled)
* For internal jumper adjustments, removeAC
cord from rear of unit and refer to aqualified service
technician. (see PCB jumper locations in fig. 5.2)
    
 

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Operating Manual -DLM-821 Stereo Ducking Line/Microphone Mixer
Ashly Audio Inc.

Fig. 5.2-DLM-821 Internal Jumper Locations
6. CONNECTIONS AND CABLES
6.1 Inputs
The DLM-821 stereo inputs use two20k ohm balanced (10k ohm unbalanced)
Euroblock connectors per channel. Wire the (+) signal to the (+) terminal, the (-) signal
to the (-) terminal, and the shield to G.Ifan unbalanced (twoconductor) input signal is
used, connect the shield to both (-) and G.
Todriveamono source into the stereo mix,simply plug the signal into the
right channel input and press the Mono switch in. Additionally, channels 1through 4
are switchable to mic level (see sec. 5.4) to add 30dB gain for microphone inputs.
6.2 Main and Mono Outputs
Outputs are 200 ohm "pseudo-balanced" Euroblock connectors, which havebal-
anced impedance with asingle-ended signal source and can bewired balanced or un-
balanced. Nominal operating level is +4dBu and maximum level is +23dBu. The
Mono output is switchable to anominal -40dBu microphone level. Ifwiring an output
as unbalanced, use the (+) and G connections.
Iflow level and high level lines (e.g., microphones and mixer line outputs),or
if either of these lines and speaker cables are run parallel for long distances, crosstalk
may besignificant. Infact, the crosstalk (signal leakage between cables) can cause an
electronic feedback loop, oscillation, and possibly damage to the equipment. Tomini-
mizecrosstalk,physically separate low level (microphone) cables from speaker cables
bythe greatest feasible distance. Atany point where cables meet, run low level cables
perpendicular to high level or speaker cables. Iflow and high level or speaker cables
must berun parallel and in close proximity to one another, they should bebundled
separately. Shielded cable should always beused for mic and line cables.
Euroblock
Input
Connections
+-G
+-G
+-G
+-G
Unbalanced
Input
Balanced
Input
+-G
+-G
+-G
+G
Unbalanced
Output
Balanced
Output
Euroblock
Output
Connections

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Operating Manual - DLM-821 Stereo Ducking Line/Microphone Mixer
7. TYPICAL APPLICATIONS
7.1 Small Sound Reinforcement System
Inthe setup shownhere, the DLM-821 is used to mix typical sound sources that might befound in asmall
club,school theater or similar environment. INPUT channels 1& 2are used for microphones for livevocal or instru-
mental pickup. INPUT channels 3-8 are used for the output of electronic music devices such as keyboards, MIDI
sound modules, drum machines, etc. The power amplifier (or any additional graphic equalizers or electronic cross-
overs which may beused) is fed from the MAIN OUTPUT connectors.
7.2 Church, School Or Meeting Room Sound System:
Here the DLM-821 is used to mix sources typically found in achurch, classroom, or meeting room. The
channel 2-4 inputs are used for microphones for livevocal or instrumental pickup. Channel 1is fed byan alarm signal
which will havepriority and fully attenuate all other inputs if it is receiving an input signal. Channels 1through 4will
havetheir Stereo/Mono switch pushed in. The remaining INPUT channels are used for audio outputs from video/DVD
players, cassette deck,CD player, computer sound card, etc. One input channel is reserved as aspare. The power
amplifier (or any additional equalizer or electronic crossover which may beused) is fed from the MAIN OUTPUT
connectors. The Mono output is connected into the wall mic jack to feed the mix into the building'smain PA system.
Here the Mono Output selector
switch should bepushed in
for amic-level signal.
Microphone
Inputs
On Ch. 2 - 4
(Mono Switch In)
Left and Right
Speakers
V /C Player
Videotape Audio
Stereo
Power Amplifier
Laptop Audio
Alarm or
Priority Override
Audio Source
(Mono Switched In)
Mono Output to
Wall Mic Input
for Secondary PA
(Set Mono Output
to Mic level)
Microphone
Inputs
On Ch. 1 and 2
(Mono Switch In)
Stereo Keyboard Input
On Ch. 3
Left and Right
Speakers
Stereo Drum Machine
Inputs On Ch.
DVD/CD Player
Midi Sound Module
Stereo
Power Amplifier
Cassette Tape

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Operating Manual - DLM-821 Stereo Ducking Line/Microphone Mixer
7.3 Restaurant/Sports Bar System:
Inthis application, avariety of line level audio signals (tape, CD,satellite background music and TV) are fed
into line inputs fivethrough eight. Talent mics are fed into inputs three and four. A host paging mic is fed into input
2which will duck (attenuate) three through eight. Anemergency paging mic is fed into input one and channel one
priority is internally selected. Anemergency page signal will then fully attenuate all other inputs. Inputs one through
four should all havetheir Stereo/Mono switches pushed in. The Mono output is fed into an existing mic mixer/PA
amplifier. The Mono output Mic/Line switch should bepushed in to giveamic-level output to this existing mic mixer.
Talent Mics
On Ch. 2 -
(Mono Switch In)
Stereo Speakers
DVD/CD Player
Satellite Background Music
Stereo
Power Amplifier
Tape
Satellite TV Audio
Host Mic
(Ducking)
Emergency
Page
(Priority
Ducking)
Outdoor
Loudspeaker
Output
8. TROUBLESHOOTING TIPS
8.1 No Sound
Check the ACpower. Isthe power switch on and illuminated? Check the level meters. Ifthey are operating,
the problem between the mixer and the later components in the system. Ifnot, check to see you really havean input
signal and that it is on the desired channel. Check that you havethe master gain controls at the desired operating level.
8.2 Distorted Sound
Something is being overdriven in the signal path. Ifthe clip indicators are active, reduce the channel level con-
trols. Ifthe clip indicators are still active, reduce the input signal level. Ifthe level meters are constantly in the red, reduce
the Master gain and increase the gain of components following the mixer. There are many gain adjustments in the mixer
itself and probably several others in other system components which makes it possible to overdrivean input section and
then incorrectly try to reduce the gain of the output section. The best way to approach setting gains is to establish the
operating level of input stages first bysetting their gain as high as possible but leaving about 20dB of headroom for loud
peaks, then moveon to set the master gain to produce agood meter reading. Proceed to set the gain of equalizers, limiters,
crossovers, and amplifiers following the mixer in the same manner, always working toward the later stages of the system.
8.3 Excessive Noise
Ifthe noise is in the form of hiss, the problem is usually due to an input stage set up for low gain and then
compensating byincreasing the master gain. Turn up the channel level controls and reduce the master gain.
8.4 Excessive hum
This is usually caused by"ground loops" in the system wiring. A complex sound system with many sources
separated bysignificant distance and using several power outlets has many opportunities for this problem to occur. If
possible, feed everything in the system from one power source with acommon ground.
Ifyou need help, get in touch with your Ashly dealer or call an Ashly technical service representativeat
1-800-828-6308.

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Operating Manual - DLM-821 Stereo Ducking Line/Microphone Mixer
9. DIMENSIONS
CROSSTALK
adjacent inputs or input to output at 1KHz ....<-80dB
adjacent inputs or input to output at 20KHz ..<-60dB
VU METERS
Two5-segment LED meters. ............0VU=+4dBu
PEAK INDICATORS
activated when internal signal is 3dB below clipping
PHANTOM POWER
Phantom power voltage ......................+18V
SHIPPING WEIGHT
10 lb (4.5kg)
NET WEIGHT
7.2 lb (3.3kg)
POWER REQUIREMENTS
98 VA C-125 VA C, 50-60 Hz,
15 watts (240 VA Cavailable)
*unless otherwise stated, specification conditions are: 150
ohm source, all levels set at nominal, outputs into 2.7k
ohm or greater.
10. SPECIFICATIONS
DISTORTION
THD at +20 dBu, 20Hz-20KHz .............<0.05%
HUM & NOISE (20Hz-20KHz)
residual output noise, all levels at minimum <-100dBu
MASTEROUT,MASTERLEVEL and one
INPUT LEVEL at nominal (unity gain) .....<-83dBu
FREQUENCY RESPONSE
20Hz-20KHz .............................±0.2dB
SIGNAL LEVELS
Maximum input level ......................+23dBu
Maximum output level .....................+23dBu
VOLTAGE GAIN (dB±1)
INPUTS
MASTEROUTPUTS(levels at nominal) ........ 0dB
INPUT to MASTEROUTPUT (levels at max) ... 25dB
Ch.1 -4INPUT in MICposition to
MASTEROUTPUTS........................ 56dB
DUCKER
Ch. 1-2 ducking threshold (mic) ............. -60dBu
Ch. 1-2 ducking threshold (line) ............. -30dBu
Ch. 3-8 default ducking level .................-20dB
Ch. 3-8 optional ducking level ................ -90dB
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0.10
6.00
(432)
1.25
(44) (29)
17.00
(152)
1.75
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1.15
(2.5)
19.00 (483)
18.375 (467)

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Operating Manual - DLM-821 Stereo Ducking Line/Microphone Mixer
11. WARRANTY INFORMATION
Thank you for your expression of confidence in
Ashly products. The unit you havejust purchased is pro-
tected byafive-year warranty. Toestablish the warranty,
besure to fill out and mail the warranty card attached to
your product. Fill out the information below for your
records.
Model Number _________________________________
Serial Number __________________________________
Dealer _______________________________________
Date of Purchase ________________________________
Dealer’sAddress ________________________________
_______________________________________
_______________________________________
Dealer’sPhone _________________________________
Salesperson ____________________________________