MCAudioLab EQ1CH User manual

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Thank you for your purchase of the MCAudioLab EQ1ch Tube Equalizer.
IMPORTANT
TABLE OF CONTENTS
Introduction 2
Warning 2
Front and rear layout 3
Features 4
Technical data 4
Functions 5 - 6
Signal flow schematic 7
Warranty - Contacts 8
Fill in the boxes above with voltage, model and your serial number to personalize your
unit . The informations and serial number can be found on the back of the product.
The serial number must be quoted in all comunication in order to obtain technical support
and spare parts.
Please register your new MCAudioLab product on “product registration” section in
www.mcaudiolab.com web site
EQ1ch Tube Equalizer MCAudioLab1

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Included in the box:
- The EQ1ch Tube Equalizer
- Power cord
- This instruction manual
Before you start your new MCATube EQ, please read the following:
Any tube product is sensitive to a high sound pressure level environment. This may cause
microphonics in a recording situation. Make sure you are able to fit shock mount and place
the unit in isolation if necessary. Direct light will also effect tubes as well.
PLEASE be sure to have enough space between any stuff; this will ensure your tube unit will
not be over heat. Over heating will cause damage to the tubes and shorten their life span.
This single-channel equalizer is a passive eq with RC - LRC circuitry and class-A triode
vacuum tube stage for the output. Input balanced signal is driven by solid state circuitry.
The RC passive shelving equalization circuitry (low freq. and High cut feq.) is based on the
classic design that is still the best-sounding way to achieve high quality tonal control. An
active vacuum tube output section has fixed gain (make-up gain) to compensate “dB” lost by
passive stage and to accomodate input signal to balanced line. The mid-high frequency
(parametric) section with boost and “Q” control is based on LRC circuitry. The EQ1ch is a
highly musical equalizer for a variety of program material from individual tracks to voices and
instruments.
The output stage utilizes the same Lundahl transformer used on the TP1ch mic preamps.
All power supplies are solid state and fully regulated
for long hum-free operation and highly filtered to avoid disturbances from the electricity
mains.. Each passive eq is hand-built and meticulously tested and listened before shipment
to the customer.
Each unit is built for a great and to last.
EQ1ch Tube Equalizer MCAudioLab2
INTRODUCTION
WARNING!

EQ1ch Tube Equalizer MCAudioLab3
FRONT PANEL REAR PANEL
EQ1ch model layout
Output
EQ1EQ1
chch
High-Q
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EQ1ch Tube Equalizer MCAudioLab4
FEATURES
Hibrid vacuum-tube and solid state design
Out level volume control
Bypass switch
True led signal level
XLR Input connector
XLR Output connector
Lundahl Output transformer
One 6DJ8 Tube
Ground lift switch (output only)
Earth lift with 4mm external plug earth connector
19”/2U-rack space
UNIT SIZE:
Width: Standard 19 inches for rack mount installation.
Height: Standard 3.50 inches or 2U rack space.
Depth: 30 cm - 12.2 inches
Weight: 5 kg - 13.2 lbs.
TECHNICAL DATA - EQ1ch specifications
Input line Impedance >10k Ohm
Balanced XLR Output (line level);
Recommended minimum load output Impedance 600 Ohm
Maximum Level +22 dBu
Output Low-Z, transformer-balanced
Power Requirements: 230 Vac - 160 Watts
Dimensions (W x H x D) 19" x 3.5" x 12.2"
Power Requirements:
230 Vac - 160 Watts
Dimensions (W x H x D) 19" x 3.5" x 12.2"
Weight 6 kg (Shipping weight 8,2 Kg.)
EQ1ch filter characteristics:
Low Boost/Cut at 20, 30, 60, 90, 120, 150Hz;
Shelving; 0 to 14dB Boost; 0 to 12dB Cut
High Cut at 4, 6, 8, 10, 12, 16, 20KHz
Shelving; 0 to 10dB
High Boost at 0.6, 1, 1.5, 2, 3, 4, 5, 8, 10, 12, 14, 16KHz;
0 to 24dB (sharp Q)
0 to 16dB (broad Q)
High Bandwidth “Q”
Sharp: 0.8 to 4 dep. on frequencies
Broad 0.2 to 1.2 dep. on frequencies
Adjustable output from - to 0 (atten. control)
In line with our company policy of continuous development, the above specifications are
subject to change without notice
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EQ1ch Tube Equalizer MCAudioLab5
OUTPUT
The output knob is master volume control (attenuation control potentiometer).
It determine the amount of signal sent to the output stage. The rang is from - (knob hard
left) to the maximum amount of gain stage (hard right).
INPUT
The rear panel XLR (balanced) input connector is optimized for low impedance audio line
signal (tip. 600 Ohm).
BYPASS switch
This toggle switch connects directly the input XLR socket to the output XLR one (pin to pin
connection). The bypass switch act only if EQ1ch is powered on.
When the bypass switch is on, the LED meter is on standby mode.
LED METER
Three led indicates the amount of signal present at the XLR output according to +4dB
standard:
The "sgn" green led indicates that a signal of (at least) -15dB is on XLR out.
The "0dB" orange led indicates that a signal of +4dB is on XLR out.
The "ovr" red led indicates that a signal of +15dB or more is on XLR out.
Values of amount signal are given by IC comparator
EQ CONTROLS
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LOW FREQ.
Rotary switch selector (A)(20, 30, 60, 90, 120, 150Hz). Use it to
select low frequencies
Low Boost (B) knob controls the amount of gain on
selected freq. The Low Boost is a shelf filter with 14dB max of gain.
Low Cut (C) knob controls the amount of attenuation on
selected freq. The Low Cut is a shelf filter with 12dB max of
attenuation. Boost and Cut controls may be used at the same time;
the cut filter action is reduced if used with boost control trim
exceedind the first quarter (K).
MID./HIGH FREQ.
Rotary switch (D) (12 steps) selector for Mid-/High freq. (600Hz; 1,
1.5, 2, 3, 4, 5, 8, 10, 12, 14, 16KHz)
Boost pot. knob (E) controls the amount of gain on selected freq. by
stepped rotary switch. The Boost is a peak parametric filter with
20dB max of gain. The maximum gain depends on the parametric
“Q” knob control position.
“Q” control knob on mid./high freq. (F)
The “Q” pot. knob control can be used to vary the “Q” factor in
mid./high filter section. It acts on boost of mid./high section control
only. The “Q” control knob makes peak filter broad or sharp
HIGH FREQ.
Rotary switch selector (G) (4, 6, 8, 10, 12, 16, 20KHz). Use it to
select high frequencies
Low Cut (H) knob controls the amount of attenuation on
selected freq. The Low Cut is a shelf filter with 10dB max of
attenuation.
FUNCTIONS
High-Q
A
B
D
G
E
H
F
k
C

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Survival Tips For Tube Equipment:
To prolong tube life, observe these simple recommendations:
After using the equipment, allow sufficient time for it to properly cool down prior to
moving it. A properly cooled gear prolongs tube life due to the internal components
being less susceptible to the damage caused by vibration.
Allow the tube to warm up to room temperature before turning it on. The heat
generated by the tube elements can crack a cold glass housing.
Protect the gear from dust and moisture. If liquid gets into, or if the gear is dropped or
otherwise mechanically abused, it must be checked out in an authorized service
center before using it.
Proper maintenance and cleaning in combination with routine checkups by your
authorized service center or dealer, will ensure the best performance and longest life
for your tube audio gear.
EQ1ch Tube Equalizer MCAudioLab6
Power
Use this switch to turn the unit on and off.
Controls primary AC power to the unit. The primary power is applied to the EQ1ch circuits
when the Power switch is in the up position. The power toggle switch connect or disconnect
the phase wire of mainAC power supply (IEC connector on the rear). When off, the apparatus
is not completely disconnected from AC power source. Detach IEC power cord if EQ is
unutilized for a long period.
GROUND LIFT
When it is activated unlinks pin 1 from signal ground (GND) to avoid hum. Ground lift acts on
XLR out connector only.
EARTH LIFT
This switch will lift the main earth connection of the chassis from signal ground (GND) so you
can avoid hum noise. Chassis is permanently earth connected via centarl pin of IEC socket.
The earth is always connected with a standard plug on the rear of each unit.
AC Plug
TP1ch uses a standard, detachable IEC power cord. Insert the AC power cord firmly into this
socket.
caution: please check to see what voltage your EQ1ch is set to. The voltage setting is marked
on the serial badge on the rear panel. Make sure the voltage is properly set for your area
before applying AC power to the unit. Check that this complies with your local supply; if not,
please notify MCAudioLab before powering up. Your EQ1ch has been factory set to the
correct mains voltage for your country. If you plan to take the unit to countries with a different
mains voltage you will need to send the EQ1ch to the MCAudioLab Service Center for the
correct transformer primaries wiring conversion and fuse changing.
Do not attempt to defeat the safety ground connection!
Fuse
This unit employs an external AC line fuse (easy access to change your fuse, as necessary )
to help protect it from damages due to overload conditions. If the fuse fails, replace it. If the
fuse fails repeatedly, discontinue use of the unit and contact MCAudioLab for service
information.
Remove the power cord before checking or changing the fuse.
To avoid any permanent damage replace fuse with the same rate and type only:
a 2A(5 x 20mm type) fuse is required for operation at 230V;
a 4A(5 x 20mm type) fuse is required for operation at 115V.
CAUTION: Tube replacement should be performed only by qualified service personnel who are
familiar with the dangers of hazardous voltages that are present in tube circuitry.

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EQ1ch Tube Equalizer MCAudioLab7
All XLR connectors are wired according to AES standard: pin 1 is ground (GND), pin 2 is “high” or “+,”
and pin 3 is “low” or “-.” A positive voltage on pin 2 of the input will result in a positive voltage on pin 2 of
the output (with the Phase Reverse switch set to Normal).
Grounding and Shields
The Input XLR connector pin 1 (GND) is directly connected to equipment ground. The GND is
connected to pin 1 of the output connector and to earth depending on earth-lift switch position.
EQ1ch signal flow schematic
electronically
servo - balanced
INPUT
Ouput
Meters
Output
Transformer
Bypass Bypass
Passive
EQ stage
Line Input Line Output

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EQ1ch Tube Equalizer MCAudioLab8
Limited 1 year Warranty
During the warranty period, MCAudioLab will repair or replace defective parts with new ones,
at no additional charge.
This warranty does not extend to any equipment that has been damaged or rendered
defective as a result of accident, misuse, or abuse; by the use of parts not manufactured or
supplied by MCAudioLab or by unauthorized modification of the equipment. Vacuum tubes
are excepted from the warranty, but are warranted for 90 days from date of purchase. Except
as expressly set forth in this Warranty, MCAudioLab makes no other warranties, express or
implied, including any implied warranty of merchantability and fitness for a particular purpose
Warranty Repair
If the EQ1ch should develop a problem during the warranty period, contact the factory to
return shipping instructions. We will repair and return your MCAudioLab equipment quickly.
Note that the warranty does not cover vacuum tubes, which must be periodically replaced.
MCAudioLab shall not be liable for technical or editorial errors or omissions in this manual, nor
for incidental or consequential damages resulting from the use of this material.
Characteristics may change without notice.
How to contact us
MCAudioLab
84/86, Viale della Rinascita
93017 San Cataldo (CL)
ITALY
[email protected]
www.mcaudiolab.com