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Operators & Service Manual
DN330
EVI PRO AUDIO GROUP Klark Teknik Building, Walter Nash Road, Kidderminster, Worcestershire DY11 7HJ England Tel: (01562)741515 Fax: (01562)745371
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DECLARATION OF CONFORMITY The Directive Covered by this Declaration 89/336/EEC Electromagnetic Compatibility Directive, amended by 92/31/EEC & 93/68/EEC Equipment Type Preset Equaliser Product Name DN330
The Basis on which Conformity is being Declared The products named above comply with the requirements of the above EU directives by meeting the following standards: EN 50081-1 (EN55022 class B) EN 50082-1 (IEC801 Part 2, 4 / ENV 50140 / ENV 50141)
Signed: Authority: Date:
........................... Head of Engineering 19th January 1996
N. G. Tembe
Attention! The attention of the specifier, purchaser, installer, or user is drawn to special limitations to use which must be observed when these products are taken into service to maintain compliance with the above directives. Details of these special measures and limitations to use are available upon request, and are also contained in product manuals.
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Attention!
Cables: This product should only be used with high quality, screened twisted pair audio cables, terminated with metal bodied 3-pin XLR connectors. The cable should be connected to pin 1. Any other cable type or configuration for the audio signals may result in degraded performance due to electromagnetic interference.
Electric Fields: Should this product be used in an electromagnetic field that is amplitude modulated by an audio frequency signal (20Hz to 20KHz), the signal to noise ratio may be degraded. Degradation of up to 60dB at a frequency corresponding to the modulation signal may be experienced under extreme conditions (3V/m, 90% modulation).
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CONTENTS INTRODUCTION THE DN330 PRESET EQUALISER INSTALLATION INSTRUMENT FAMILIARISATION AUDIO CONNECTIONS SPECIFICATIONS SERVICE INFORMATION SCHEMATICS 8 9 11 13 14 15 16
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THANK YOU FOR USING THIS KLARK TEKNIK PRODUCT To obtain maximum performance from this precision electronic product, please study these instructions carefully. Installing and operating the equaliser is not complicated, but the flexibility provided by its operating features merits familiarisation with its controls and connections. This unit has been prepared to comply with the power supply requirements that exist in your location. Precautions Before connecting this unit to the mains power, ensure that the operating voltage is correct for your local supply. Do not install this unit in a location subjected to excessive heat, dust or mechanical vibrations. Safety Warning This unit is fitted with 3-pin power socket: For safety reasons the earth lead should not be disconnected. To prevent shock or fire hazard, do not expose the unit to rain or moisture. To avoid electrical shock do not remove covers. Refer servicing to qualified personnel only.
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After you have unpacked the unit Save all the packing materials - they will prove valuable should it become necessary to transport of ship this product. Please inspect this unit carefully for any signs of damage incurred during transportation. It has undergone stringent quality control inspection and tests prior to packing and left the factory in perfect operating and mechanical condition. If, however, the unit shows a sign of damage, notify the transportation company without delay. Only you, the consignee, may institute a claim against the carrier for damage during transportation. If necessary, contact your supplier or as a last resort, your Klark Teknik importing agent, who will fully co-operate under such circumstances.
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Introduction The equaliser is a vital component in any audio system. The entire signal passes through it and so any limitations imposed by the equaliser will compromise the performance of the whole system. For example, an indifferently designed equaliser may introduce severe phase distortion, noise and other anomolies related to centre-frequency accuracy, filter shape and attenuation accuracy which may manifest themselves as an overall deterioration in the perceived sound quality of the system. Clearly this in an unacceptable state of affairs, but fortunately your choice to utilise Klark Teknik equaliser product will eliminate these problems, offering you unprecedented product performance coupled with the highest filter calibration and reliability standards in the industry. For many years Klark Teknik has been at the forefront of equaliser design, and have carried out detailed research into optimum filter response characteristics, including their sonic performance. The Series 300 range of equalisers is a direct result of this research. It should be noted that equalisation cannot always overcome all frequency response related problems. There are applications where the ability to cut or boost the response at a particular frequency, or over a certain bandwidth other than the equaliser specified one, is required to overcome exceptionally difficult response anomalies or narrow band feedback problems. When such an instance is encountered, it may be more appropriate to use the greater range of control provided by a parametric type equaliser, where the centre frequency, bandwidth and amplitude are all controllable. When using an equaliser remember that the need to use large amounts of boost or cut within the equalisation curve indicates that there may be something fundamentally wrong with the sound system or room acoustics, which should be further investigated and corrected before final equalisation is applied. Both the input and output circuitry is electronically balanced. The input is voltage and current matched and gives exceptional noise, distortion and CMR performance, while the output circuitry is based on the Midas XL3 output stage giving high drive capability. Operation is normally from the mains supply with the 24V DC supply being utilised upon the failure of the mains. If no 24V is available then the internal relays will bypass the unit in the event of power failure.
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DN330 Equaliser The Klark Teknik DN330 is a single channel, 30 band equaliser offering 12dB of cut or boost in 1/3 octave steps between the frequencies of 20Hz and 20kHz. Filter Shape and Combining Action At the heart of any equaliser is the bank of filters used to shape the signal response, and Klark Teknik utilise a proprietary filter circuit which replaces which replaces the conventional inductor based circuit, at the same time, offering several performance advantages. Inductor based circuits are heavy, expensive to produce and suffer from low frequency distortion and induced hum. Klark Teknik's proprietary filters on the contrary suffer none of these problems, yet offer unequalled phase response and control accuracy with the additional benefits of low noise and minimal ripple. The nature, shape and way in which individual equaliser filters combine, has a profound effect on the control provided by the equaliser and on the resulting quality of sound. The majority of applications within the sound reinforcement, broadcast and recording fields, require a smooth and continuous equalisation response curve in order to correctly contour the overall response characteristics of a sound system, loudspeaker, recording effect or audio channel. To achieve this, the individual filters must be capable of combining smoothly together to result in a continuous response curve, free from shape discontinuities in order to avoid unwanted audible peaks of anomalies in the final sound. Individual channel level controls, overload indicators and bypass switches with incorporated low cut filters are featured on the control panel. Other features The bypass switch silently removes the graphic equaliser sections from the signal path. The equaliser also incorporates variable low and high pass 12dB/octave filters with a range from 2K5Hz to 30kHz and 15Hz to 300Hz respectively. Other features include an overload LED per channel, which warns of impending overload at any point in the equaliser. A detachable security cover is an inherent feature to prevent unauthorised personnel from tampering with the control settings. This product is built to the same high electrical and mechanical standards as all Klark Teknik equipment and is both robust and stylish. It occupies a standard one unit of rack space and has electronically balanced inputs and outputs.
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Reliability Control Even with the advanced technology incorporated in this product, each instrument is given the full backing of Klark Teknik's "reliability control" which proves each product against a specification consistent with the highest professional standards. Only top quality components are used, and every unit is bench tested and aligned before a burn-in period and final performance test.
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INSTALLATION The DN330 is designed for fixed installations where it is conventionally mounted into a standard 19" equipment rack. The unit occupies only 1U of height and due to the low operating power requirements of this unit, heat generation is kept to a minimum allowing units to be stacked above each other with no ill effects. For continued reliability it is not recommended that the equalisers are located immediately above heat generating units such as power amplifiers or mixer power supplies. If this is unavoidable a vent panel between the units is advisable. Precautions Do not install this unit in a location subjected to excessive heat, dust or mechanical vibration. before connecting the unit to the mains supply, ensure that the operating voltage is correct for your local supply. It is important that you observe the following precautions. Voltage Selection & Power Connection Connection to the mains supply is by means of a standard IEC power socket. The rear panel voltage label indicates the voltage required for satisfactory operation of the unit. To change the mains voltage please refer to the ` Voltage Changeover` section on page 12. IMPORTANT Mains voltage adjustments should only be carried out by a qualified service technician. The DC supply can be connected either by separate 4mm ( Banana ) plugs or by use of the dual stacking version. Correct polarity must be observed for operation, though the unit is protected against reverse polarity. Please refer to the section below regarding DC operation. NOTE: As there is no power on/off switch on this unit, as soon as the power (Mains or DC ) is connected the unit will be active. Safety Warning This unit is fitted with a 3-pin power socket. For safety reasons the earth lead MUST NOT be disconnected. An internal `floating' audio ground reference is used to ensure no earth loop problems occur related to the installation of this unit. Should any ground loop problems be encountered they will be caused by the commoning of the grounds of the other equipment connected to the equaliser. The DN330 can be made the central ground reference as detailed on page 12, this modification should only be carried out by qualified service technician. To prevent shock or fire hazard, do not expose the unit to rain or moisture, only replace fuses with the correct type and rating. Do not remove the covers, refer servicing to qualified personnel only.
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Audio Connections The inputs and outputs are fully balanced on XLR connectors and are wired conventionally with pin 1 as ground. Because the system is fully floating, either pin 2 or pin 3 can be designated as hot (phase ) so long as the same protocol is adhered to for both inputs and outputs. To comply with EMC regulations filtering is incorporated into this unit. To maximise the benefits of this it is recommended that the XLR shell is not connected to the audio ground. DC Operation This unit is designed primarily for operation from the mains supply. The DC connection is intended for use as a backup power for evacuation and similar uses in conditions of mains failure. Upon failure of the mains supply, as the unit is already operational the DC supply is only required to furnish the current necessary to maintain operation, nominally 200mA at 24V. If it is required to power the unit only from the DC supply, this is quite acceptable but the power supply MUST be capable of providing an initial 1.5A start up current to initiate the switched mode power supply. The duration of this current draw is only for approximately 5 milliseconds after which the current drops to 200mA. This is no problem when running from batteries but could overload a bench power supply. Please refer to the application note later in the manual for a method of starting and running from a supply that only gives 250-300mA .
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Front Panel Functions
Other than the power on and clip indicators no user controls or indicators are available with all setup controls secured behind the central removable panel. Remove the three pozidrive screws to gain access to these controls. 1. Input level control allowing system gain of up to +12dB in the fully clockwise position and attenuation of up to -6dB in the fully anticlockwise position. When the `slot' is horizontal it is in the 0dB, unity gain position. EQ in/out switch. This switch allows the bypassing of the equaliser selected as follows: Down: Equaliser & filters bypassed. The gain control is still active. Up: Equaliser in circuit. The low frequency filter (high pass) has a continuously variable turnover frequency from 15Hz to 300Hz. The high frequency filter (lo pass) has a continuously variable turnover frequency from 2.5khz to 30KHz. Thirty high quality, sealed rotary preset filter level controls each providing between +12dB boost and -12dB cut at the 1/3 Octave ISO standard frequencies. When the "slot" is hori zontal the filter is flat. Overload led. The signal level is monitored at several separate points within the circuitry of the unit. If any one of these signals exceeds a threshold set 3dB below clipping the led will light. It must be remembered that excessive boost at some frequencies combined with a high average input signal can occasionally cause the clip sensing threshold to be exceeded. In this event the gain control should be turned down to correct the problem. However, if the input signal itself exceeded 20 dB the input stage will be overloaded. If this problem arises then the signal level from the equipment feeding the equaliser must be reduced.
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Rear Panel Functions 7. Mains is supplied via an IEC standard 3 pin connector. A compatible power cord is supplied with the unit. 8. The mains fuse is located in the draw that is part of the mains input connector. A spare fuse is also stored here. Disconnect the unit from the mains supply before replacing the fuse. Always replace the fuse with the correct type and rating. 9. Two sockets are provided for the connection of the 24V DC supply. These are standard 4mm `banana' type. The sockets are on a standard 19mm pitch to allow the use of twin stackable connectors. The polarity of the DC supply must be maintained for operation though incorrect connection will not damage the unit. 10. Input and output connections are via complementary XLR style connectors. For wiring details see the page entitled Audio Connections. NOTE: The security cover is normally fixed with M3 pozidrive screws. For installations where the utmost security is required these can be replaced with tamperproof type of M3 x 6mm. Audio Connections Inputs The input circuitry is a transformerless, electronically balanced design which achieves a symmetry of better than -50dB from 20Hz to 10kHz. It is always preferable to drive the equaliser from a balanced source. If only an unbalanced source is available it is recommended that it is connected as shown below. Connect the screen only at the equaliser end.
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Outputs The standard outputs are electronically balanced and is capable of driving +19dBu into 600 ohms and +20dBu into 2K. It is recommended that the equaliser feeds into a balanced input, however to feed an unbalanced input it is necessary to connect the antiphase output to ground. This is best carried out on the XLR output connector of the equaliser. Note: When using a fully balanced system, either pin 2 or pin 3 can be phase.
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Technical Specifications Input Type Impedance Balanced Unbalanced Max input level Output Type Source impedance Min.load impedance Max.level Performance Frequency response 20Hz to 20kHz, EQ flat THD+N @ +4dB Equivalent input noise (20Hz to 20kHz unweighted) Gain Filters Type ISO centre frequencies Frequency tolerance Maximum boost/cut High pass filter Low pass filter Power requirements AC Voltage Consumption DC Voltage DC Consumption Weight Nett Shipping Dimensions Width Height Depth Terminations Inputs Outputs AC power DC power One Electronically balanced 20Kohms 10Kohms 20dBm One Electronically balanced 50 ohms 600 ohms 20dBu with 2Kohm load
+/-0.5dB <0.01% @ 1kHz <-86dBu -6 to +12dB Proprietary "combining" 30, 25Hz to 20kHz 5% +/-12dB 15Hz to 300Hz, 12dB/octave 2K5Hz to 30KHz, 12dB/octave 115/230 +/-12%, 50/60Hz <15VA 24V +/-12% <250mA 2.5kg 4kg 482mm (19 inches) 45mm (1 3/4 inches) 210mm (8 1/4 inches) 3 pin XLR 3 pin XLR 3 pin IEC 2x4mm "Banana" type
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THE FOLLOWING INFORMATION IS FOR THE USE OF QUALIFIED SERVICE PERSONNEL ONLY Do not attempt any of the following adjustments yourself The following adjustments require the removal of the cover. Proceed as follows:1. 2. Disconnect the unit from the mains and DC supply. Remove the eight pozidrive cover screws, 3 on the top, 2 on each side and 1 Keep these safe for reuse later. Lift off the cover. on the rear.
Voltage Changeover The unit is normally shipped preset to the mains supply voltage required for the country. This is indicated on the rear panel. To select the alternative voltage it is only necessary to slide the voltage selector switch, located to the right of the mains transformer, to the other position. Please ensure that the rear panel voltage label is removed and replaced with one stating the new voltage setting.
Making the DN330 the system ground reference Under certain unusual operating environments it may be necessary to use the equaliser as the main ground reference and tie other signal grounds to it. This is easily accomplished as follows:1. Remove the M3 pozidrive screw located in the centre of the board labelled `ST3.' & `Ground Link'. Fit a solder tag onto the screw and refit ensuring the tag is located over the bare pcb section to the left of the screw. Solder the tag to the circuit board. Replace the cover after adjustment.
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KLARK TEKNIK
Application Note 1
A Method of Starting & Powering the DN320 & DN330 from a 24V Bench Supply.
CAUTION.
The following is given as guidance only and should only be carried out by suitably qualified and experienced personnel. The information is given in good faith and is not intended as a definitive method of achieving the desired results.
Problem: "I only have a 250-300mA 24V power supply. How can I run the DN330 from it?" Answer: 1. 2. 3. 4. With the supply OFF, connect a capacitor of approximately 10000 mfd and a working voltage of at least 25V across the output terminals. Connect the power supply to the DN330 via a suitable switch, leave in the open position. Turn on the power supply and allow a couple of seconds for the capacitor to charge. Close the switch and the DN330 will power up.
It does this because the capacitor provides sufficient energy to provide the switch mode supply's start up current. Once the supply is running only the nominal 200mA operating current is required.
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