Orban 672A Manuals

672A Equalizer OPERATING MANUAL EQUALIZER Specifications: 672A Equalizer All specifications apply when driving 600 ohms or higher impedances. Noise mea- sured on an average -reading meter through a 20-20,000Hz bandpass filter with 18dB/ octave Butterworth skirts. Electrical Input: Impedance, Load (each leg): 100K in paral- lel with lOOOpF, electronically balanced Impedance, Driving: Ideally 600 ohms or less, balanced or unbalanced Nominal Input Level: Between -10 and + 4dBm Absolute Overload Point: + 26dBm Output: Impedance, Source: 47 ohms in parallel with lOOOpF, unbalanced (Optional trans- former balanced 600 ohm outputs) Impedance, Load: Should be 600 ohms or greater-will not ring into any capacitive load Nominal Output Level: +4dBm Max. Output Level Before Clipping: + 19 dBm, 20 -20,000Hz Frequency Response: 1 0.25dB, 20 - 20,000Hz: EQ controls set at “O” detents Available Gain: + 12dB; adjustable to — infinity by means of front -panel GAIN control Slew Rate: Varies between 6 and 13V/uS depending upon setting of GAIN control; slewing is symmetrical. Internal bandlimiting assures that slew rate limiting will not occur even with the most severe equalization and pro- gram material. Square Wave Response: Square wave exhibits no spurious ringing at any output level. The only ringing observ- able is that theoretically associated with any given equalization curve. Total Harmonic Distortion: Less than 0.05%, 20 -20,000Hz ( + 18dBm) SMPTE Intermodulation Distortion: Less than 0.05% ( +18dBm: 60/7000Hz,4:l) Noise at Output: Less than -75dBm (EQ in, Filters out, Controls centered) Overload /Noise Ratio: Better than 113dB for any single bandpass filter, for any settings of TUNING or BAND- WIDTH controls. Equalization Ranges: + 16dB peaking EQ, Reciprocal Tuning Ranges: 20 -60Hz;40 -150Hz; 110-310Hz; 230- 750Hz; 480 - 1900Hz; 1.1- 4.5Hz; 2.8-9.0kHz; 5.9 -21kHz. Dials calibrated at ISO preferred frequencies. “Q” Range: Greater than 0.5 to 10 for any setting of the TUNING control Low Pass Filter Section: Tunable in 2 ranges: 200 -2000Hz or 2.0- 20kHz, 12dB/octave, (2nd-order Butterworth) High Pass Filter Section: Tunable in 2 ranges: 20 - 200Hz or 200 - 2000Hz, 12dB/octave, (2nd-order Butterworth) Overload Circuit: Lamp lights for 200mS if the instantaneous peak output of any amplifier rises to within ldB of its clipping point. Circuit Design: Active RC realized with FET-input opamps. Line driver employs discrete transistor cur- rent booster. Operating Temperature: 0-50°C Power Requirements: 115/230VAC 1 10%; 50/60Hz; 6 watts Physical Operating Controls: EQUALIZATION, TUNING, and BAND- WIDTH for each of eight bands. TUNING, RANGE (xl; xlO), and FILTER IN/OUT for each filter. EQUALIZATION IN/OUT, POWER ON/OFF, and GAIN for entire equalizer. Panel: 19” x 5V4” (48.3 x 13.3cm): 3 units Chassis Depth Behind Panel: 51/4 ” (13.3cm) Weight: Net: 8 lbs. (3.6kg); Shipping: 12 lbs. (5.4kg) AC Cord: 3-wire U-ground to USA Standard Connectors: 140 type barrier strip (# 5 screw) plus paral- lel-wired V4” 3 ckt. phone jacks (Switchcraft 12B or equal). Holes punched for XLR-type connectors (Switchcraft D3F and D3M or equal) Circuit Ground: Available on barrier strip; normally jumpered to chassis. Specifications subject to change without notice. Table of Contents Specifications < Registration Card Warranty * I Part A: Installation and Operation I Introduction 1 Performance Highlights 2 Front Panel Description 3 Rear Panel Description 3 Block Diagram 3 AC Power 3 Mechanical Installation 4 Installation of Options XLR Connector Installation Balanced Output Tranformer Installation 5 Electrical Installation Input Output Wiring With Two-Conductor Shielded Cable Grounding Diagram Typical Input/Output Connection Rules Wiring Wi‘h Single-Conductor Shielded Cable 8 OPERATING INSTRUCTIONS Using the EQ Section Boost/Cut Curve Familes Using the Highpass and Lowpass Filters Using the 672A As An Electronic Crossover Headroom I | Part B: Specific Applications I I Stereo | | Sound Reinforcement House Tuning « Notch Filtering Full Electronic Crossover Partial Electronic Crossover and i Individual Driver Equalizer Stage Monitors 13 Dance Bars 14 Recording Studios 14 Motion Picture Sound 15 Broadcasting 15 Electronic Music 1 7 Part C: Maintenance 17 Introduction 17 Performance Evaluation Genera I Power Supply Signal Processing Circuitry 20 Maintenance and Service Preventive Maintenance Access Replacement of Components on Printed Circuit Boards Troubleshooting 1C Opamps Factory Service Shipping Instructions 23 Circuit Description Genera I Input Buffer Equalizer Sections EQ IN/OUT Switch Lowpass Filter Highpass Filter; Output Buffer Overload Indicator Power Sipply 27 Appendix: Interconnections And Grounding 27 Driving the Input From High-Impedance And/Or High-Level Sources 27 Grounding 29 PARTS LIST 35 SCHEMATIC 36 PARTS LOCATOR INTRODUCTION PERFORMANCE HIGHLIGHTS Part A: Installation and Operation The Orban 672A is a single-channel eight-band quasi-parametric equalizer of high professional quality. It is equipped with graphic-type EQ controls providing up to l6dB of reciprocal boost or cut. The center frequency and bandwidth of each band are continuously variable to enable precise control of the audio spectrum. Wide- range high- and low-pass filters ( 1 2dB/octave) follow the EQ section for added versatility. When these filters are overlapped (200-2000Hz), the 672A can be used as a combined graphic/parametric equalizer and tunable electronic crossover. Separate lowpass and highpass outputs are provided for this purpose. The 672A has an electronically-balanced bridging input, and unbalanced outputs (which can be balanced by the addition of optional output transformers). Input, outputs, and power line connections all contain effective RF filtering. l2dB of gain is available. All potential overload points in the equalizer are monitored by an extremely fast "peak-stretching" overload detector, so that peak clipping can be detected and corrected before if becomes audible. The flexibility offered by the 672A makes it a particularly powerful tool in nearly all areas of audio: sound reinforcement, public address, recording studio, broadcasting, motion picture sound, disco, theater. The 672A easily meets the quality, performance, and reliability requirements of the demanding professional, and is also well-suited for use in semi-pro or audiophile applications. The controls and features of the 672A are fully described in this manual. It will familiarize you with the unit's potential and enable you to imaginatively use the 672A for your specific installation and application. EQ Section Eight bands, each with TUNING and BANDWIDTH control + l6dB equalization range Reciprocal curves Each band tunes over 3:1 frequency range "Q" is variable between 0.5 and 10 — "Tic" marks on TUNING and BANDWIDTH controls guide you to octave-band graphic equalization settings Bands are totally non-interacting LP/HP Filter Sections Each section is continuously tunable over 100:1 range in 2 decades !