Professional Stereo Amplifiers

Transcription

1 Symbol Professional Stereo Amplifiers ENGLISH FBT elettronica S.p.A. - Via Paolo Soprani 1 - Zona Ind.le Squartabue RECANATI (MC) - ITALY TEL. 071/ r.a. - FAX 071/ info@fbt.it

2 INDEX Introduction Precautions Unpacking Warning Front panel / Rear panel Controls Installation Connections and power-up Operating modes Cables and connectors Block diagram Technical specifications Technical glossary Problems and solutions INTRODUCTION Here are the no-compromise power amplifiers! The new Symbol Power Amplifier series features two models based on a project design targeted to obtain the most appropriate technical solutions to each and every need of signal amplification. The Symbol and the Symbol grant stereo power output of respectively 1500 W and 2400 W per channel (into 2 ohm). All the steps followed for this project have been directed to the achievement of the maximum performance at every stage of application: nothing has been saved from this mission! The application of Cascode circuits, of over-dimensioned final stages, of highly efficient techniques such as the use of power supply at 2 or 3 steps and the highest capacity of electricity distribution... The great quality of these amplifiers guaranteed by the traditional FBT reliability and the rich equipment of technical features, place the Symbol and Symbol to the top of the range and confirm FBT s target to offer the right audio solution to every need. TECHNICAL CHARACTERISTICS: > XLR connectors for signal inputs and outputs > electronically balanced inputs > power outputs with 4-pole Speakon connectors > facility for operation in parallel, mono or stereo modes > power line thermal cut-out protection > independent protections on each channel > soft start function > delayed activation of outputs > dual loudspeaker protection to safeguard against continuous voltage on output (relay) > short-circuit protection on outputs > SOA protection > clip limiter > 8 dual-colour LED s providing comprehensive at-a-glance display of operating modes > ground lift switch 2 1

3 PRECAUTIONS - Read this manual thoroughly and observe the following precautions before working with the amplifier. - Take care not to spill liquids onto the amplifier and do not use it in excessively humid conditions. - Do not install the amplifier near heat sources or expose it to direct sunlight and do not install in dusty environments without suitable protection. - Do not obstruct the air intake openings or the cooling fans. - Ensure the power supply voltage does not exceed the value shown on the rear panel. - Do not use the amplifier unless the mains cable and plug are in perfect condition (replace or repair if necessary). - To safeguard against induced interference, do not install the amplifier next to transformers, television sets, RF transmitters, motors or electrical power sources of any description. - Do not use solvents such as acetone or alcohol to clean the amplifier or the finish and panel lettering will be damaged. - Do not connect output channels to input channels of other appliances and do not connect the CH1 OUT/CH2 OUT power outputs to any load other than the relative input connector on the loudspeakers. - Do not connect audio inputs to electrical power sources of any type. - If a fault occurs, consult your nearest FBT service centre or a specialized audio equipment repair service. Do not attempt to repair the amplifier yourself. UNPACKING Although all FBT products are carefully inspected and tested before shipment, they could be damaged in transit. When removing the packing material inspect the amplifier carefully for any sign of damage. Inform your dealer immediately if the amplifier is damaged on arrival. Keep the packing material on hand so that it can be re-used if the amplifier must be shipped to a service centre at any time or in the event of resale. Note that this type of equipment holds its market value well, provided it is kept in good condition and can be supplied in its original packing together with the handbook. WARNING < CAUTION RISK OF ELECTRIC SHOCK DO T OPEN! TO REDUCE THE RISK OF ELECTRIC SHOCK DO T REMOVE COVER (OR BACK) USER SERVICEABLE PARTS INSIDE REFER SERVICING TO QUALIFIED SERVICE PERSONNEL TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK DO T EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE 2

4 FRONT PANEL Symbol Active/PRT Stereo Bridge Active/PRT ULTRA LINEAR Status/Clip Parallel Ground Lift Status/Clip CASCODE CIRCUITS REAR PANEL GND LIFT < CAUTION MADE IN ITALY ON RISK OF ELECTRIC SHOCK DO T OPEN OFF TO REDUCE THE RISK OF ELECTRIC SHOCK DO T REMOVE COVER (OR BACK) USER SERVICEABLE PARTS INSIDE REFER SERVICING TO QUALIFIED SERVICE PERSONNEL ON 2 OHM MIN. 4 OHM MIN. 2 OHM MIN. INPUTS OUTPUTS PARALLEL (CH1) 230 V LINE PROTECT 12 A M P CONTROLS DESCRIPTION 1] Ch1 / Ch2 Volume control knob (Channel 1 and Channel 2). Volume control range is from 0 (no signal) to 10 (full volume). 2] Active / PRT Dual-colour LED: green indicates that the relative channel can operate correctly; red indicates that a protection 0 10 has tripped and the channel is on standby. Protections may trip for the following reasons: a) overheating: in this case the amplifier will resume normal operation after a brief interruption for cooling purposes; at this point the LED changes from red to green, confirming that normal operating status of the Symbol power amplifier has been restored. b) in the case of a fault the LED will remain red permanently and the amplifier must be taken to a service centre. When the system is powered on the LED shows a red light for a few seconds, confirming activation of the automatic function protecting the loudspeakers from power surges at start-up. Active/PRT 3

5 CONTROLS DESCRIPTION 3] Status / Clip Amplifier operating status indicator LED: - green indicates that the amplifier is functioning normally - red indicates that the signal has reached the saturation threshold (clipping level) in the amplification stage (in this case reduce the volume by means of the Ch1 / Ch2 (1) controls). Status/Clip ] Stereo This LED illuminates when the Symbol power amplifier is functioning in stereo mode (refer to the Operating Modes chapter). 5] Parallel This LED illuminates when the Symbol power amplifier is functioning in parallel mode (refer to the Operating Modes chapter). 6] Bridge This LED illuminates when the Symbol power amplifier is functioning in bridge mode (refer to Operating Modes chapter). Stereo Parallel Bridge Ground Lift 7] Ground lift This LED illuminates to indicate that the amplifier input ground is isolated from the ground of connected equipment (see description -13-). 8] Power switch: In an audio system it is good practice to switch on power amplfiers last and switch them off first to avoid possible signal peaks. 9] Ch1 / Ch2 inputs Inputs with XLR connectors. The inputs are compatible with balanced signals from mixer outputs; the two sockets for each channel are connected in parallel so that one can be used as an input and the other to patch the signal to another amplifier. INPUTS 10] Ch1 / Ch2 outputs Outputs with Speakon connectors. For connecting loudspeakers to both amplification circuits. Loudspeakers must have minimum impedance of 2 ohms and power handling of at least 1500W (Symbol 12000) or 2400W (). 2 OHM MIN. 2 OHM MIN. OUTPUTS 4

6 CONTROLS DESCRIPTIONS 11] Bridge output Mono output with Speakon connector. To connect a loudspeaker to both amplifier circuits in mode. The loudspeaker (or array of loudspeakers connected in series/parallel) must have minimum impedance of 4 ohms and power handling of at least 3000W (Symbol 12000) or 4800W (). 4 OHM MIN. OUTPUTS 12] Stereo-Parallel-Bridge Three-position mode selector :-PARALLEL- (refer to Operating Modes chapter). Use this selector only when the amplifier is powered off. PARALLEL (CH1) 13] GND LIFT Switch for electrical isolation of the ground circuit from the earth circuit; this function can be used to eliminate hum caused by ground loops. GND LIFT ON OFF ON 14] Mains cable Cable with plug for connection to the electrical mains supply (230V). 230 V 15] Line protect Thermal cut-out to disconnect the power supply in the event of excess current absorpotion. To restore normal operation of the amplifier press the LINE PROTECT button. LINE PROTECT 12 A M P 5

7 INSTALLATION SYMBOL amplifiers are designed for rack mounting (two standard 19" rack spaces) and are supplied with four fixing holes on the front panel flanges. The rear panel features two pins (A) designed to engage in the rack. The amplifier is equipped with two cooling fans operating at variable speed in relation to the temperature. For efficient operation of the amplifier, ensure that the rear panel air expulsion grilles are unobstructed. If possible, do not install the amplifier in places subject to direct sunlight, high temperatures, high levels of dust or humidity. SIDE VIEW DO T OBSTRUCT THE AIR INTAKE OPENINGS OR EXPULSION GRILLES A CONNECTIONS & POWER UP Before connecting any other equipment, ensure that the amplifier is powered off and that the power supply data corresponds to the specifications on the rear panel of the SYMBOL power amplifier. Make sure the volume controls are set to 0 to avoid possible damage to the loudspeakers. Also ensure that the operating mode selector is positioned as required:, PARALLEL or. N.B. POWER OFF THE AMPLIFIER BEFORE CHANGING THE POSITION OF THE MODE SELECTOR 6

8 OPERATING MODES When the input signal is stereo, use mode, selectable on the rear panel. The left hand and right hand channel signals must be connected to the amplifier INPUT1 and INPUT2 respectively. The signal will be amplified in stereo and delivered to the OUT1 and OUT2 outputs; the left-right output balance can be set using the two volume controls. MIXER SPEAKER CABINET SPEAKER CABINET GND LIFT < CAUTION RISK OF ELECTRIC SHOCK DO T OPEN TO REDUCE THE RISK OF ELECTRIC SHOCK DO T REMOVE COVER (OR BACK) USER SERVICEABLE PARTS INSIDE REFER SERVICING TO QUALIFIED SERVICE PERSONNEL MADE IN ITALY ON OFF ON PARALLEL (CH1) INPUTS 2 OHM MIN. 4 OHM MIN. 2 OHM MIN. OUTPUTS 230 V LINE PROTECT 12 A M P For mono input signals use PARALLEL mode, selectable on the rear panel. Mono signals should be connected exclusively to INPUT1. The mono signal will be amplified by both channels and delivered to outputs OUT1 and OUT2 at a volume that can be set independently using the two volume controls. PARALLEL MIXER PARALLEL SPEAKER CABINET SPEAKER CABINET GND LIFT < CAUTION RISK OF ELECTRIC SHOCK DO T OPEN TO REDUCE THE RISK OF ELECTRIC SHOCK DO T REMOVE COVER (OR BACK) USER SERVICEABLE PARTS INSIDE REFER SERVICING TO QUALIFIED SERVICE PERSONNEL MADE IN ITALY ON OFF ON PARALLEL (CH1) INPUTS 2 OHM MIN. 4 OHM MIN. 2 OHM MIN. OUTPUTS 230 V LINE PROTECT 12 A M P When working with a mono input and single loudspeaker line, you can use the entire power available from the two output stages by selecting mode on the rear panel. The signal must be connected exclusively to INPUT1. The signal will be delivered to the OUTPUT and amplified with double the available power with respect to the normal type of connection. MIXER CH1 SPEAKER CABINET GND LIFT < CAUTION RISK OF ELECTRIC SHOCK DO T OPEN TO REDUCE THE RISK OF ELECTRIC SHOCK DO T REMOVE COVER (OR BACK) USER SERVICEABLE PARTS INSIDE REFER SERVICING TO QUALIFIED SERVICE PERSONNEL MADE IN ITALY ON OFF ON PARALLEL (CH1) INPUTS 2 OHM MIN. 4 OHM MIN. 2 OHM MIN. OUTPUTS 230 V LINE PROTECT 12 A M P 7

9 CABLES & CONNECTORS Always use top quality cables and connectors when connecting the amplifier output to the loudspeakers and the inputs to a mixer. Check cables and connectors before powering on the amplifier; if cables and connectors are damaged, they must be replaced or properly repaired before using the amplifier. SPEAKON Positive 1 - Negative XLR Connections side Wirings side Massa Schermo (Ground) 2. Fase + Caldo (Hot) 3. Fase - Freddo (Cold) 3 BLOCK DIAGRAM BOOSTING POWER SUPPLY CH2 level clip OUT POWER AMP AUX POWER SUPPLY fan PROTECT OUT AUX CH SW PARALLEL level POWER AMP fan clip OUT 1 BOOSTING POWER SUPPLY 8

10 Active/PRT Status/Clip 0 10 Stereo Parallel Bridge Ground Lift 0 10 Active/PRT Status/Clip CASCODE CIRCUITS TECHNICAL SPECIFICATIONS Symbol ULTRA LINEAR Symbol Continuous power both channels driven W RMS 0.05% 1kHz) 2x700W 8 ohm 2x1300W 4 ohm 2x1800W 2 ohm 2x550W 8 ohm 2x900W 4 ohm 2x1300W 2 ohm Continuous power Bridge mode W RMS 2600W 8 ohm 3600W 4 ohm 1800W 8 ohm 2600W 4 ohm Impulsive power both channels driven W RMS 2x800W 8 ohm 2x1500W 4 ohm 2x2400W 2 ohm 2x3200W 1 ohm 2x600W 8 ohm 2x1000W 4 ohm 2x1500W 2 ohm 2x2000W 1 ohm Impulsive power Bridge mode W RMS 3000W 8 ohm 4800W 4 ohm 6400W 2 ohm 2000W 8 ohm 3000W 4 ohm 4000W 2 ohm Input sensitivity 2 Veff 1,7 Veff Input impedance 15k ohm 15k ohm Slew rate >40V/µS >40V/µS Signal to noise ratio >110dB A weighted >110dB A weighted THD ( 1 khz-4ohm) 1W full power < 0.02% < 0.02% IMD 1W full power < 0.05% < 0.05% Frequency ±0.2 db 20Hz - 20kHz 20Hz - 20kHz Max current output 80A eff 60A eff Power consumption 3500 VA 2700 VA Power supply 230 V 230 V Protections DC/Thermal/SOA/Soft Start DC/Thermal/SOA/Soft Start Cooling 2 variable speed fans 2 variable speed fans Dimensions (WxHxD) mm 482 x 88 x x 88 x 460 Weight kg Inputs XLR-F XLR-F All power measurements made at 230V All measurements made using AUDIO PRECISION equipment Impulsive power measured in accordance with IHF method with 20mS bursts and REPETITION RATE 100mS 9

11 TECHNICAL GLOSSARY Balanced and unbalanced - A connection is balanced when the signal is carried by two conductors (hot and cold) and a screening braid. The hot pin has the job of carrying the in-phase signal, while the cold one carries the same signal, but out of phase. This method enables to make transmitted signals immune to electromagnetic interference even over long lines, thanks to the fact that when the two signals reach the receiving device, they are algebraically subtracted one from the other, producing a new signal with twice the amplitude and eliminating the interference along its path. Bridge- Indicates an electrical configuration of two power amplifiers that makes it possible to double the output power delivered to a single loudspeaker line. In this mode the "bridge" connects the two power amplifiers to the same input signal but with a 180 degree reversal in phase. The loudspeaker is connected across the two positive binding posts on the amplifier output. Some amplifiers are able to assume this configuration by means of a switch and dedicated mono output. Ground - Electrical reference point for a signal travelling round a circuit or along a cable. The ground generally has a value of zero volts and is carried by audio cables by means of a metal sheath which also has the function of screening the signal (i.e. protecting it from external electromagnetic interference. Earth- The ground (or earth) in an electrical device is represented by the physical connection of the metal parts exposed to the user and a cable in the power plug (the middle pin). By means of the mains power supply, the ground cable (normally recognizable for its yellow/green colour) is connected to a metal pole hammered into the ground, often in the basement of the building itself. The aim of the ground system is to disperse in the ground any current which in the event of faults could electrocute a user when touching the metal parts of the unit in question. The dispersion of energy is sometimes also used to eliminate any audio hum, which can be achieved by means of a capacitive connection between the signal ground and the amplifier ground, or even a physical connection. THD - Total Harmonic Distortion. This value indicates the relationship between the effective value of the spurious harmonics generated by the system in question and the effective value of the fundamental sine wave used in the test. THD is normally expressed as a percentage. Tone burst - The measurements carried out in laboratories to test amplifiers' power don't take into consideration the constant electrical variations which a complex audio signal can have through time. Nowadays power is expressed in peak Watts (as far as the response of an output stage with extremely brief transients states is concerned), musical Watts (which indicate the hypothetical power on a stable sinusoidal signal) and RMS Watts (which measure the real power, but referred to a stable repetitive complex signal). The measurement technique with Tone Burst signals is extremely significant as it cyclically recreates the possible dynamic range which a normal audio signal can have through time. This system ensures a control of the quality and capacity of the output transistors and above all of the power supply contained in the amplifier being tested. Watts RMS - This is a measurement which expresses the effective value of the power, i.e. the real amount of power which a system is able to deliver. RMS (Root Mean Square) is the mathematical method used to calculate the effective power: the square root of the mean (average) of the sum of the squares of the harmonics contained in the spectrum. The RMS Watts are exactly half the musical Watts and an eighth the peak/peak Watts. 10

12 PROBLEMS AND SOLUTIONS FAULT TEST SOLUTION FLOW DIAGRAM LEGEND No sounds come from the loudspeakers and PROTECT led is red The loudspeakers have a background hum Is the amplifier very hot? Are the front panels air vents and the fans outlets free from all obstacles? When the final stage reach excessively high temperatures the electronic protections trip, putting the system on standby Is the GROUND LIFT selector in the OFF position? Avoid installation close to electrical equipment which from strong magnetic fields (dimmers, transformers, etc.) and use well screened (and if possible balanced) connector cables Switching the amplifier off and on again after a few minutes does the fault still occur? The heat produced by the power circuits is dispersed by the fans, which take in air through the vents on the front panel and sent it out through rear panel Set the selector at ON to avoid dangerous ground loops A momentary overload has occurred which has tripped the protection devices The amplifier s final stages have burnt out. Contact an authorized assistance centre The loudspeaker output signal distorted The power ON indicator doesn t light up Is the CLIP led lit red? The signal being fed into the amplifier must be lowered. The volume controls enable the input signal to be set at an ideal level, indicated by the green colour of the CLIP led Does another unit connected to the same powersocket switch on? Has the fuse on the rear panel blown? Replace with a new fuse There s an external problem. Check the quality of the signal directly at the audio source Check the socket s switches and electrical connections Contact an authorized service centre 11

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