Model ASC 4 BAND PARAMETRIC EQUALIZER Reference Manual speck electronics
Warranty Speck Electronics products are warranted to the original owner to be free of defects in material or workmanship. This warranty does not apply to any product subject to accident, misuse, neglect or failure to comply with normal maintenance procedures or if the serial number has been defaced, altered, or removed; nor will Speck Electronics accept responsibility for damages resulting from improper installation, alteration or unauthorized parts or repairs.
iii Contents Chapter 1 Introduction General ...................................................................................... Standard Accessories ................................................................. Model PS-4 power module .................................................. Hardware.............................................................................. Operator Safety Summary ......................................................... Power source ....................................
iv Chapter 3 Operation (continued) Gain Control ......................................................................... Bypass Switch...................................................................... Power/Bypass LED .............................................................. L - Low Band Controls ........................................................ L/M - Low/Mid Band Controls ............................................ M - Mid Band Controls....................................................
Chapter 1 Introduction Section speck electronics Model ASC L si 55 30 L/M 150 40 400 0 M 230 500 5K 70 700 90 20 0 1 800 8K 700 400 0 H 2.5 6.2 10K 5.5 4K 0 si 11 16 25K 4 Band Equalizer 0 Gain _ 12 +6 _ 15 BYPASS IN +15 LOW MID _ 15 _ +15 15 +15 _ 15 +15 Figure 1a.
Chapter 1 2 Introduction Section Introduction General Thank you for purchasing our Model ASC Equalizer. The Model ASC has operational features that are easy to understand and you should be up and running in no time. If you are unfamiliar with audio equipment or audio signal flow, it is recommended that you read this manual. If you have any questions regarding the Model ASC or any Speck product, do not hesitate to contact Speck Electronics. Our phone number is +760-723-4281.
Chapter 1 Introduction Section 3 Standard Accessories Model PS-4 power module module. The power module has a 6' two conductor cable and is fitted with a special 4 pin Molex connector for mating to the “Power” input on the rear of the ASC. All AC rectification, filtering, and DC regulation is performed within the chassis of the Model ASC. The PS-4 power module is available in 2 versions; a North American version and European version.
Chapter 1 Introduction Section 4 Specifications Normal Input Level +4 dBu Output Level: (Active Balanced) (Transformer Balanced) Normal +4 dBu +4 dBu Maximum +24dbu Maximum +28dbu +24dBu Input Impedance 20K Ohms Output Impedance (Active Balanced) (Transformer Balanced) 120 Ohms 600 Ohms Output Distortion(THD+n) 22Hz to 22KHz @ +24dBu .0014% Frequency Response Test Conditions: AP balanced +4dBu signal connected to input. Gain control set to “0” position.
Chapter 2 5 Installation Section Installation General The following information should give you the basics on how to install the Model ASC and PS-4 power module. The proper installation of the Model ASC as part of a larger system requires a clear understanding of audio wiring, AC distribution, grounding, and shielding techniques. When the Model ASC is being installed into a larger system it may be necessary to retain the services of someone experienced in these matters.
Chapter 2 Installation Section 6 Because the power module uses a 2 bladed AC plug, audio signal grounds and DC common at the Model ASC are isolated from the AC safety earth. The chassis of the ASC can be connected to earth by way of the chassis ground terminal on the rear panel. Mechanical Installation The location of the Model ASC should be such that the operator has a clear, unobstructed view of the front panel from his/her normal operating position.
Chapter 2 Installation Section 7 The power module normally generates a small amount of heat during operation. It is important that adequate ventilation is provided when planning the mounting location. The external power module does not provide an AC power switch. It is recommended the power module be plugged into an AC power strip that uses a power switch. Fuse replacement The PS-4 power module has an internal “one shot” thermal fuse. Fuse replacement is not possible with this module.
Chapter 2 8 Installation Section Cleaning The front and rear panels are a high quality painted surface and the panel lettering is applied using a silkscreen printing technique. To clean the front or rear panel, wipe the surface gently using a soft lintfree cloth to avoid scratching the panel or markings. Paper towels are not recommended.
Chapter 2 9 Installation Section OUTPUT GND LIFT BAL. XLR BAL. ¼ UNBAL.¼ HIGH LOW GND PIN2 PIN3 PIN1 TIP RING SLEEVE TIP INPUT SLEEVE Figure 2. Input & Output Connectors The Input The input of the ASC has a balanced 1/4” jack and a balanced XLR connector (Figure 2). These inputs are internally wired in parallel and there is no operational difference between one or the other. The two inputs can not be used simultaneously.
Chapter 2 10 Installation Section Connecting the Model ASC to inserts When connecting to an audio mixer, you may choose to connect the ASC to the insert points of the input channel. A mixer’s insert point (access point) exist exclusively for the access of devices such as the Model ASC, limiters, compressors, gates, etc. These aforementioned devices are regarded as “processing” equipment and are normally connected (inserted) into a single channel.
Chapter 3 Operation Section 11 Operation General We hope to give you basic information on the operation of the Model ASC and adequately describe its controls, switches, and connectors. The information in this manual is intended to help with the technical process when using your Model ASC. Words alone could not adequately describe how to adjust the controls on the Model ASC. Your ears should be your best gauge of how to adjust the equalizer controls to make the sound fit your requirements.
Chapter 3 12 Operation Section FRONT PANEL CONTROLS 1. Gain Control 2. Equalizer bypass switch This control is used to adjust the input sensitivity between -12dB and +6dB relative to the level that is present at the input connector. The center detented position is “0” unity gain. Under normal operation with a balanced input and balanced output, this control can be set to the “0” position. In cases when the ASC is interfaced to an unbalanced device, a 6dB loss may occur.
Chapter 3 13 Operation Section 5. Low boost/cut 6. Peak/Shelf Switch The boost/cut control provides a reciprocal volume adjustment of the selected frequency control. This means that whatever frequency is "boosted" with the boost/cut adjusted from its center position clockwise, an identical but opposite result is achieved when that same frequency selection is "cut" from its center position counterclockwise.
Chapter 3 14 Operation Section 8. Low/Mid frequency sweep The low/mid frequency sweep control is used in conjunction with its respective boost/cut control and provides continuous adjustment of the center frequency from 40Hz (fully counterclockwise) to 800Hz (fully clockwise) for the low range selection or 400Hz (fully counterclockwise) to 8kHz (fully clockwise) for the mid range selection. 9.
Chapter 3 15 Operation Section M (Mid) BAND 11. Mid frequency sweep 12. Mid boost/cut 13. Mid bandwidth adjust The mid frequency sweep control is used in conjunction with the mid boost/cut control and provides continuous adjustment of the center frequency from 400Hz (fully counterclockwise) to 10KHz (fully clockwise). 11 M 2.5 700 6.
Chapter 3 Operation Section 15. High boost/cut 16 frequency range (4kHz to 25kHz), and is used in conjunction with the high frequency sweep adjust. 0dB (flat) is obtained when this control is set to its center detented position. In addition to the ability to contour high band audio, the high band controls can reduce hiss that is present on low frequency information.
Chapter 3 17 Operation Section REAR PANEL OUTPUT BAL. XLR BAL. ¼ UNBAL.¼ HIGH LOW GND GND LIFT 18 16. Input Connectors 17 PIN2 PIN3 PIN1 TIP RING SLEEVE TIP INPUT SLEEVE 16 Two types of input connectors are available on the ASC; a standard 1/4" TRS balanced jack and a female XLR connector. These inputs are internally wired in parallel and identical in every aspect except for the connector. The 1/4” jack will accept a balanced TRS plug or a mono TS unbalanced plug.
Chapter 3 18 Operation Section Hence, there is not a right or wrong position for a ground lift switch. If either position improves an otherwise hummy-buzzy situation, that is the right position. 19 speck electronics Model ASC - 4 BandEqualizer S/N Fallbrook, California OUTPUT TRANSFORMER OPTION POWER AUX DC I/O USE WITH PS-4 POWER MODULE USE WITH SPECK PRODUCTS ONLY 21 20 19.
Chapter 3 19 Operation Section 22. Chassis Ground 23. Aux DC I/O Because the ASC uses an external power module, the chassis is not automatically earth grounded. If you experience hums or buzzes, this screw may be used to connect the chassis of the ASC to known earth such as an AC receptacle cover plate. This connector is available to provide a source of dual regulated DC voltage to an external device. This connector is reserved for future Speck products.
Chapter 4 Wiring and Other 20 Wiring and Other General The following information is not specific to the operation of the Model ASC, but rather general information regarding the “care and feeding” of an audio system. A general discussion about AC, AC grounding, audio grounding, EMI, and quality wiring is discussed in this section. These subjects are very often overlooked or misunderstood, and should be given consideration when interfacing your equipment to any audio product.
Chapter 4 Wiring and Other 21 AC Distribution and Safety Proper AC grounding When you are evaluating voltage and current requirements for your audio system, it is important that your Model ASC equalizer and/or audio system does not exceed the capacity of your AC service.
Chapter 4 Wiring and Other Electronics earth 22 In an electronics context, an earth provides a path for unwanted EMI noise to be carried away from your audio equipment. If you disable your earth with a ground lift or do not have a reliable earth connection, the unwanted noise (EMI or RFI), will find an electrical path of least resistance. That will most likely be your audio equipment and would result in unwanted buzzes or hums.
Chapter 4 Wiring and Other 23 Almost every electronic device generates some amount of EMI emissions. These emissions can be transmitted as electromagnetic radiation or simply conducted though audio cables and power cords. In the same respect, most electronic devices are also very susceptible to the EMI emissions generated by other electronic devices. Sources of EMI There are natural and man made sources of EMI that you can't do anything about.
