DOD SR231QX DUAL 31-BAND GRAPHIC EQUALIZER

SR231QXLR Graphic Equalizer
   
The SR231 QXLR combines two constant Q, 31-band, 1/3 octave
equalizers into a two rack space steel chassis. The back panel
boasts XLR, and 1/4 inch connectors. With a fully shielded internal
power supply, and unsurpassed specifications, the SR231QXLR is
the perfect choice where ever stereo, or dual equalizers are needed. 

The AD2055 combines 100% discrete, pure class A signal amplifiers with state-of-
the-art passive and active filter topologies. The AD2055's unique circuitry delivers
very high resolution transient detail at the operational extremes of real world equalization
demands. The AD2055 auto-bias DC servo loop control eliminates the need for all
interstage capacitor coupling. The AD2055 breathes life into all musical performances!
 
AD2055 FEATURES
Pure Class A, 100% discrete design
Smooth musical detail and sonic excellence
Minimum audio signal path
Dual mono operation
Transparent active and passive filter design
High headroom +30dB Very low noise -94dB
Fully balanced inputs and outputs
DC coupled, no transformers in audio path
Switched frequencies in high and low bands
Mid bands use X10 frequency for extended range
Wide bandwidth -3dB 1Hz to 450kHz
Low distortion less than 0.5% THD and IMD
All signal routing with sealed silver relays Conductive
plastic potentiometers for low noise
External 150W toroidal power supply 100% discrete
power supplies for audio path
Long lasting, stainless steel hardware
 
SONIC EXCELLENCE
The Avalon AD2055 Pure Class A music equalizer is the most powerful, low noise
parametric equalizer available today. Designed to optimize absolute signal integrity
and musical performance, the AD2055 combines the best of active and passive filter
topologies with sonic excellence unequaled by lesser designs. The AD2055 is the
perfect solution for two buss music-program equalization, special instrument EQ and
FX applications and ultra high performance mastering studio's.

Features include state-of-the-art, balanced 100% discrete, Pure Class A signal amplifiers,
practical user features and rugged hardware designed to deliver true high performance
audio for many years. 

PASSIVE-ACTIVE FILTER DESIGN
Avalon equalizers feature the unique combination of both active and passive filter EQ designs.
This special combination enables the AD2055 to deliver high speed transient detail at the
operational extremes of real-world equalization demands. The passive high and low bands offer
alternate musical tone range to the full function active parametric mid bands. Passive equalizers
have long been a favorite with music lovers around the world.  Full bodied, powerful (up to +/-32dB,
64dB range !) and sweet frequency selections are the benefits of the passive high-low EQ bands.
The full bandwidth twin mid bands provide variable frequency selection (X10 frequency multipliers
for very wide range), variable Q (width) and amplitude control.

MINIMUM SIGNAL PATH DESIGN
Avalon's advanced true symmetry design offers high-voltage, large headroom, extended bandwidth
and very low noise. The use of 100% discrete, Pure Class A signal amplifiers give the serious music
professional unlimited sonic character and a natural harmonic detail that enhances the program
material and becomes one with the music itself. The Avalon AD2055 breathes life!

AD2055 SPECIFICATIONS
Circuit Topology  High-voltage 100% discrete, balanced and symmetrical
Class A 
Output Gain Range  Unity Gain 
Maximum Input Level  +30dB balanced XLR pin 2 hot 
Maximum Output Level  +32dB balanced 600 ohms, DC coupled, high-current
discrete Class A 
Input / Output Type  XLR type, pin 2 hot balanced 
Noise 20kHz Unweighted  -94dB (EQ in) 
Distortion THD, IMD  0.5% (typical 0.05% at +6dB 1kHz) 
Frequency Response -3dB  1Hz to 450kHz (input band limited) 
Equalizer Type  Passive high and low bands plus two fully parametric mid
bands 
Bypass  Hard-wire relay bypass for equalizer in-out 
Low Band F1  Passive, amplitude to -32dB to +32dB shelf or peak-dip curve 
F1 Frequency Range  Switched 10 position 18Hz, 25, 30, 50, 72, 100, 150, 215,
300, 450Hz 
Mid Band F2  Active, amplitude to -16dB to +16dB peak-dip curve 
F2 Frequency Range  Variable 35Hz to 450Hz (x10) 350Hz to 4k5Hz, Q (width)
0.3 to 3.0 
Mid Band F3  Active, amplitude to -16dB to +16dB peak-dip curve 
F3 Frequency Range  Variable 160Hz to 2k0Hz (x10) 1k6Hz to 20kHz, Q (width)
0.3 to 3.0 
High Band F4  Passive, amplitude to -26dB to +26dB shelf or peak-dip curve 
F4 Frequency Range  Switched 10 position 1k5Hz, 2k5, 3k5, 5k, 7k2, 10k, 12k5,
15k, 20k, 25kHz 
AC-DC Power  External AC supply, 150w toroidal transformer, 4 pin cable 90v
isolated, 
(B2T Power Supply Included)  100-240v selectable 50/60Hz, 150w max 
Dimensions  19 x 3.5 x 12 in (482 x 88 x 305mm) 
Shipping weight  30lbs (13.6 kg) 

INPUT

Connectors: 1/4" TRS, female XLR (pin 2 hot)

Type: Electronically balanced/unbalanced, RF filtered

Impedance: Balanced 40k ohm, unbalanced 20k ohm

Max Input Level: >+21dBu balanced or unbalanced

CMRR: >40dB, typically >55dB at 1kHz

OUTPUTS

Connectors: 1/4" TRS, male XLR (pin 2 hot)

Type: Impedance-balanaced/unbalanced, RF filtered

Impedance: Balanced 100 ohm, unbalanced 50 ohm

Max Output Level: >+21dBu balanced/unbalanced into 2k ohm or greater

>+18dBm balanced/unbalanced (into 600 ohm)

SYSTEM PERFORMANCE

Bandwidth: 20Hz to 20kHz, +0.5/-1dB

Frequency Response: 50kHz, +0.5/-3dB

Dynamic Range: Typically >112dB

Signal-to-Noise: Typically >95dB

THD+Noise:

• Audiophile 31-band stereo graphic equalizer for live and studio applications
• Revolutionary FBQ Feedback Detection system instantly reveals critical frequencies and can also be used as audio analyzer
• Ultra-low noise 4580 operational amplifiers for highest signal integrity
• Dedicated Limiters with gain reduction meters for each channel protect your sound system from overload and distortion
• Pink noise generator provides test signals to adapt your sound system to any room acoustics
• Mono subwoofer output with dedicated level control and adjustable crossover frequency
• Additional sweepable high and low-cut filters for each channel remove unwanted frequencies e.g. floor rumble, hiss etc.

• Highly accurate 8-segment LED input/output metering and input gain controls for easy level setting
• Relay-controlled hard bypass with an auto-bypass function during power failure (fail-safe relay)
• Servo-balanced inputs and outputs with 1/4" TRS and gold-plated XLR connectors
• “Planet Earth" switching power supply for maximum flexibility (100
  - 240 V~), noise-free audio, superior transient response plus low power consumption for energy saving

* 2 channel 15 2/3 octave band graphic equalizer
* 25Hz - 16kHz frequency control * Constant Q circuitry
(3% frequency accuracy) * Selectable 6dB or 12dB control
* Variable level control * By-pass switch * Overload threshold LED (5dB below clipping) * Ground lift switch * XLR & 1/4" TRS balanced Inputs/Outputs * Power: Selectable 120V/220V voltage
* Dimensions: 1.75" H x 19" W x x 8.5" D / 44.5mm x 483mm x 216mm - 1 space r.m. * Weight: 4.5 lbs. / 2.5kg

XEQ-152 Specifactions:
* Input type: Active balanced / Unbalanced * Output Impedance: