® The dbx 12 Series were designed to meet the needs of the most demanding sound reinforcement environments, while offering the simplicity of straightforward controls. The 1231 provides standard features like dual-channels, 31 1/3 octave bands, ISO frequency centers, +/- 12 dB input gain range, and switchable 40Hz/18 dB per octave low- cut filters, but also includes other insightful features. These include 45 mm faders; selectable +/-6dB or +/-15dB boost/cut range for precise gain adjustments; XLR, barrier strip, and 1/4” TRS connectors for installation ease; balanced inputs and outputs for quiet operation; and chassis/signal ground lift capabilities for quick hum isolation. The visionary design of the dbx 12 Series makes your job easier. The dbx 12 Series Equalizers were precision engineered to provide years of maintenance- free operation in any application. The magnetically isolated transformer, electronically balanced/unbalanced inputs and servo balanced/unbalanced outputs, RF-filtered inputs and outputs, and power-off hard-wire relay bypass with 2 second power up delay were steps our engineers took to ensure compatibility for all installations. Only the best components were utilized, yielding a 10Hz to 50kHz frequency response, greater than 90dB SNR (ref +4dBu), less than 0.005% THD +Noise (1kHz at +4dBu), and interchannel crosstalk of less than -80dB from 20Hz to 20kHz. All this attention to detail is contained in a 3U steel/aluminum chassis. It’s no wonder that dbx has been a leader in the industry for over 25 years. • Switchable Boost/Cut range between ±6dB and ±15dB • Electronically balanced/unbalanced inputs • Servo balanced/unbalanced outputs • RF filtered inputs and outputs • XLR, Barrier Strip, and 1/4" TRS connectors • -12dB/+12dB input gain range • 18dB/octave 40Hz Bessel low-cut filter • Chassis/signal ground lift capability 8760 S. Sandy Pkwy. • Internal power supply transformer Sandy, Utah 84070 Phone (801) 568-7660 • Power-off hardwire relay bypass with 2-second power-up delay Fax (801) 568-7662 Int’l Fax (801) 568-7583 customer@dbxpro.com http://www.dbxpro.com A Harman International Company 18-1779-A 07/99 -10 0 +10 +18 +6 +15 OUTPUT LEVEL (dBu) CLIP +/-15 0 +/-6 0 0 -12 +12 dB EQ INPUT LOW RANGE BYPASS GAIN CUT -6 -15 1231 20 25 31.5 40 50 63 80 100 125 160 200 250 315 400 500 630 800 1k 1.25k 1.6k 2k 2.5k 3.15k 4k 5k 6.3k 8k 10k 12.5k 16k 20k Graphic Equalizer -10 0 +10 +18 +6 +15 OUTPUT LEVEL (dBu) CLIP +/-15 0 +/-6 0 0 -12 +12 dB EQ INPUT LOW RANGE BYPASS GAIN CUT -6 -15 1231 DUAL CHANNEL 31 BAND EQUALIZER -10 0 +10 +18 10 6 3 1 +6 +15 OUTPUT LEVEL (dBu) CLIP +/-15 0 +/-6 0 0 -12 +12 dB EQ INPUT LOW RANGE BYPASS GAIN CUT -6 -15 1231 20 25 31.5 40 50 63 80 100 125 160 200 250 315 400 500 630 800 1k 1.25k 1.6k 2k 2.5k 3.15k 4k 5k 6.3k 8k 10k 12.5k 16k 20k Graphic Equalizer -10 0 +10 +18 +6 +15 OUTPUT LEVEL (dBu) CLIP +/-15 0 +/-6 0 0 -12 +12 dB EQ INPUT LOW RANGE BYPASS GAIN CUT Dual Vacuum Tube Preamp -6 -15 586 OUTPUT INPUT TYPE IV™ Conversion System POWER OUTPUT INPUT OUTPUT INPUT 704 + - - + CAUTION: T O REDUCE THE RISK OF FIRE REPLACE RISK OF ELECTRIC SHOCK ONLY WITH SAME TYPE FUSE. DO NOT OPEN ATTENTION: UTILISER ATTENTION: RISQUE DE CHOC ELECTRIQUE - NE PA S OUVRIR UN FUSIBLE DE RECHANGE DE WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC MEME TYPE. SHOCK DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE CONNECTOR POLARITY PHONE: XLR: TIP PIN 1 24 WATTS RING PIN 2 SLEEVE PIN 3 OUTPUT INPUT PROFESSIONAL PRODUCTS A HARMAN INTERNATIONAL COMPANY MODEL 1231 MANUFACTURED UNDER ONE OR MORE OF THE FOLLOWING OUTPUT INPUT GRAPHIC EQUALIZER OUTPUT INPUT U.S. PATENTS: 4,234,804 4,316,107 4,329,598 4,331,931 4,377,792 4,403,199 4,409,500 4,425,551 4,434,380 4,454,433 4,471,324 + - - + 4,473,793 OTHER PATENTS PENDING 100V 50/60Hz 120V 60Hz The graphic equalizer shall be a dual 31-band type with frequency centers on standard ISO Inputs Interchannel Crosstalk: <-80dB, 20Hz to 20kHz one-third octave frequencies ranging from 20Hz to 20kHz. The boost/cut ranges shall be Connectors: 1/4" TRS, female XLR (pin 2 switchable via recessed front panel switches to either +/-6dB or +/-15dB and the selected hot), and barrier terminal strip range shall be indicated on the front panel by either of two LEDs per channel. Low-noise Type: Electronically Function Switches equalization sliders having a 45mm travel shall be utilized having center detents at 0dB. balanced/unbalanced, RF EQ Bypass: Bypasses the graphic equalizer The equalizer shall have front panel 41-detent rotary input gain controls having a +/-12dB filtered section in the signal path range. Bypassing the equalizer sections of the signal path shall be accomplished via front- Impedance: Balanced 40kΩ, unbalanced Low Cut (recessed): Activates the 40Hz panel switches having corresponding LEDs to indicate when each channel is bypassed. A 20kΩ 18dB/octave Bessel high-pass 40Hz low-cut Bessel filter per channel with 18dB/octave slope shall be insertable in the Max Input Level: >+21dBu balanced or filter signal path via front panel recessed switches with an LED to indicate when the filter is unbalanced Range (recessed): Selects either +/- 6dB or +/- CMRR: >40dB, typically >55dB at 15dB slider boost/cut range active. Output levels shall be monitored on four-LED peak-reading bar graphs calibrated to 1kHz read -10, 0, +10, and +18dBu. Indicators Electronically balanced/unbalanced inputs shall include 1/4" TRS, female XLR, and screw Outputs Output Level: 4-LED bar graph (Green, terminal barrier strip, while servo-balanced/unbalanced outputs shall include 1/4" TRS, Connectors: 1/4" TRS, male XLR (pin 2 Green, Yellow, Red) at -10, 0, male XLR, and screw terminal barrier strip shared with the input. A circuit/chassis ground hot), and barrier terminal strip +10, and +18dBu lift jumper per channel shall be strapped across circuit ground and chassis ground screw Type: Impedance- EQ Bypass: 1 LED: red balanced/unbalanced, RF Clip: 1 LED: red terminals and shall be removable by the user. Inputs shall be electronically filtered Low Cut: 1 LED: red balanced/unbalanced and RF filtered having a nominal input impedance not less than 40kΩ Impedance: Balanced 200Ω, unbalanced +/-6dB: 1 LED: yellow balanced and 20kΩ unbalanced, and shall accept maximum signal levels of not less than 100Ω +/-15dB: 1 LED: red +21dBu. Outputs shall be servo-balanced/unbalanced and RF filtered having a nominal Max Output Level: >+21dBu balanced/unbalanced output impedance of not more than 200Ω balanced and 100Ω unbalanced, and shall be into 2kΩ or greater Power Supply capable of driving not less than +21dBu into 2kΩ or greater and not less than +20dBm (into >+18dBm Operating Voltage: 100VAC 50/60Hz, 120VAC 600Ω) continuously. balanced/unbalanced (into 60Hz, 230VAC 50/60Hz 600Ω) Power Consumption: 1215 24W; 1231 24W Frequency response shall be better than 10Hz to 50kHz, +0.5/-3dB. Signal-to-noise ratio Mains Connection: IEC receptacle shall be greater than 90dB, referenced to +4dBu. THD+Noise shall be less than 0.005% System Performance with a 1kHz signal at +4dBu, while interchannel crosstalk shall be lower than -80dB from Bandwidth: 20Hz to 20kHz, +0.5/-1dB Physical 20Hz to 20kHz. Frequency Response: <10Hz to >50kHz, +0.5/-3dB Dimensions: 1215: 3.5" H X 19" W X 7.9" D (8.9cm x 48.3cm x 20.1cm) The internal power supply shall be constructed using a thermally-fused transformer +/-15dB range +/-6dB range 1231: 5.25" H X 19" W X 7.9" mounted in a low hum orientation and shall be magnetically isolated from equalizer D (13.4cm x 48.3cm x 20.1cm) circuitry by means of a mu-metal shield. The power cord shall be detachable from an Dynamic Range: 109db 115db Weight: 1215: 8.5 lbs. international standard IEC 320 power inlet receptacle. Unit shall be constructed to meet or Signal-to-Noise: 90db 97db 1231: 10.6 lbs. exceed all applicable international safety and regulatory agencies. Domestic unit shall be THD+Noise: <0.005% Shipping Weight: 1215: 9.5 lbs. powered from 100VAC 50/60Hz, 120VAC 60Hz, while international unit shall be powered from 230VAC 50/60Hz. Unit shall consume no more than 24W. Housing shall be of all steel/aluminum construction and shall be rack-mountable in an IEC standard 19" rack and shall occupy a 3U (5.25") rack space. The unit shall be a dbx 1231 FOR MORE INFORMATION CONTACT: Equalizer. dbx Professional Products 8760 S. Sandy Pkwy. dbx engineers are constantly working to improve the quality of our products. Specifications are, therefore subject to change without notice. Sandy, Utah 84070 Phone (801) 568-7660 ® Fax (801) 568-7662 Int’l Fax (801) 568-7583 customer@dbxpro.com http://www.dbxpro.com A Harman International Company