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Related Manuals for L-Acoustics LA15a
Summary of Contents for L-Acoustics LA15a
- Page 1 Version 1.0 January 2003 LA15a 115V Version OWNERS MANUAL...
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Page 3: Table Of Contents
8.2 Thermal Protection ........................19 8.3 VHF Protection..........................19 8.4 Short Circuit Protection ......................19 8.5 AC Mains Voltage Protection ...................... 20 8.6 DC Protection ..........................20 9. MAINTENANCE..........................20 9.1 Troubleshooting .......................... 20 L-ACOUSTICS LA15a 115V Manual V1.0 27/01/2003... -
Page 4: List Of Figures
Table 4: LA15a Maximum Output Power versus Mains Input Power ..........12 Table 5: LA15a Output Power and Input Sensitivity versus MLS Switch Setting (32 dB gain)....13 Table 6: Maximum Recommended Length for Damping Factor > 20 ..........16 L-ACOUSTICS LA15a 115V Manual V1.0... -
Page 5: Approvals
5. Clean only with a dry cloth. 6. Do not block the air intake or exhaust ports. Install the unit in accordance with the instructions outlined in this manual. L-ACOUSTICS LA15a 115V Manual V1.0 27/01/2003... -
Page 6: User Responsibility
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection L-ACOUSTICS LA15a 115V Manual V1.0 27/01/2003... - Page 7 Increase the separation between the equipment and receiver. • Connect the equipment to an outlet on a circuit different from that to which the receiver is connected. • Consult the dealer or an experienced radio/TV technician for further assistance. L-ACOUSTICS LA15a 115V Manual V1.0 27/01/2003...
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Page 8: Introduction
3. INTRODUCTION Thank you for purchasing the L-ACOUSTICS LA15a power amplifier. This manual contains important information on operating your power amplifier correctly and safely. Please take time to read this manual in order to familiarize yourself with the many advanced features of this amplifier. -
Page 9: Rear Panel
7. Power Switch Turns the mains power on or off. 3.3 REAR PANEL Figure 2: LA15a Rear Panel 1. Output Speaker Connector The Neutrik® Speakon connector may be unfamiliar to some users. See Section 6.2 for details. 2. Minimum Load Selector (MLS™) Switch These switches are used to select the maximum output power. -
Page 10: Rear Panel Features
MLS positions when connected to lower speaker impedances and as can be seen in Table 1, the LA15a can produce output power in excess of 380 watts. Essentially, the LA15a amplifier is a power converter and by selecting MLS positions you are allocating a portion of the available 1200 watts power. -
Page 11: Clip Limiter
MLS positions can be different for each channel and a variety of combinations can be selected as seen in Table 2. There is no risk for amplifier damage since the LA15a is very well protected (even down to 0.3 ohms). However, if uncertain or where time does not allow, use the default position (MLS = 0 dB). -
Page 12: Installation
5. INSTALLATION 5.1 MOUNTING The LA15a is two rack units high (2U) and will mount in an EIA-standard 19'' rack. Four mount points are provided on the front panel of the amplifier for rack mounting. For permanent installation, the amplifier can be mounted using standard 19'' rack mount rails and/or slides within the amplifier rack using the four front mount points. -
Page 13: Grounding
L-ACOUSTICS switch mode amplifiers use primary switching, i.e. the mains power is rectified directly before the transformer, which means that the power supply is insensitive to the mains frequency and will operate from DC to 400 Hz. If the supplied power plug is not appropriate for your country, it can be cut off and wired to a suitable... -
Page 14: Heat Power Calculation
9 dB of headroom (which is very low for normal audio program). Table 4: LA15a Maximum Output Power versus Mains Input Power MAXIMUM OUTPUT POWER MAINS INPUT POWER... -
Page 15: Gain And Sensitivity
Since the output power delivered varies with the load impedance, 4 ohms is generally taken as the reference. For the LA15a, peak output power into 4 ohms is 600 W (MLS switch = 0 dB) and standard gain is 32 dB. This corresponds to an input sensitivity of 1.22 Vrms or 4.4 dBu. -
Page 16: Connections
Balanced signals are less sensitive to AC hum and radio interference. The source impedance should be less than 1 kOhms in order to avoid high frequency loss in long cables. Figure 7: LA15a Rear Panel Detail L-ACOUSTICS LA15a 115V Manual V1.0 27/01/2003... -
Page 17: Unbalanced Inputs
LF or HF component of your active loudspeaker system. As standard, L-ACOUSTICS active 2-way loudspeakers are cabled as follows: LF +/- = 1+/1- (Ch A) ; HF +/- = 2+/2- (Ch B). The same convention holds for the Channel C/D output connector, i.e., LF +/- = 1+/1- (Ch C) ;... -
Page 18: Operation
Formerly, this was referred to as reverse stereo operation for the LA15. For this reason, be sure to use balanced inputs on all measurement equipment (also oscilloscope probes) if you are bench testing. Figure 11: Reverse polarity operation for Channels B and D L-ACOUSTICS LA15a 115V Manual V1.0 27/01/2003... -
Page 19: Tandem Mode
4 ohm part of the load and the other channel shares the other 4 ohm part. The power into 4 ohms from an LA15a (MLS at -3 dB) is 380 W. Therefore, the total bridged power into the 8 ohm load will be 2 x 380 = 760 W. -
Page 20: Powering Up - Soft Start
In bridged mode, both controls must be in the same position so that the speaker load will be shared equally between the channels. 7.5 INDICATORS Figure 13: LA15a Front Panel Detail The two bottom green ”ON” LED’s indicate that the output circuits are receiving the correct rail voltage. -
Page 21: Protection Features
Under normal operation, clip limiting is inaudible. The limiter can be turned On or Off by depressing or pressing the relevant rear panel clip limit switch. L-ACOUSTICS recommends leaving the clip limiters switched ON at all times (Channel A, B rear panel clip limiter buttons depressed in the “IN” position). -
Page 22: Ac Mains Voltage Protection
In the unlikely event of a non-user rectifiable fault, return the amplifier to your supplier or an approved service centre (see Section 11). L-ACOUSTICS cannot be held responsible for damage or injury as a result of the top or bottom covers being removed. -
Page 23: Warranty
This warranty shall be null and void, if the product is subjected to: 1) Repair work or alteration by persons other than those authorised by L-ACOUSTICS or its agents. 2) Shipping accidents, war, civil insurrection, misuse, abuse, operation with incorrect AC voltage, operation with faulty associated equipment, exposure to inclement weather conditions and normal wear and tear.
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