Electro-Voice PA Series Power Amplifiers
Owner's Manual
Models: PA1250T, PA2250T, PA2400T, PA2450L, PA4150L
Important Safety Instructions
WARNING: CONNECT ONLY TO MAINS SOCKET WITH PROTECTIVE EARTHING CONNECTION.
- Read these instructions.
- Keep these instructions.
- Heed all warnings.
- Follow all instructions.
- Do not use this apparatus near water.
- Clean only with a dry cloth.
- Do not cover any ventilation openings. Install in accordance with the manufacturer's instructions.
- Do not install near heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.
- Do not defeat the safety purpose of the polarized or the grounding-type plug. A polarized plug has two blades with one wider than the other. A grounding type plug has two blades and a third grounding prong. The wide blade or the third prong are provided for your safety. If the provided plug does not fit into your outlet, consult an electrician for replacement of the obsolete outlet.
- Protect the power cord from being walked on or pinched particularly at plugs, convenience receptacles, and the point where they exit from the apparatus.
- Only use attachments/accessories specified by the manufacturer.
- Unplug this apparatus during lightning storms or when unused for a long period of time.
- Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been damaged in any way, such as power-supply cord or plug is damaged, liquid has been spilled or objects have fallen into the apparatus, the apparatus has been exposed to rain or moisture, does not operate normally, or has been dropped.
- Do not expose this equipment to dripping or splashing and ensure that no objects filled with liquids, such as vases, are placed on the equipment.
- To completely disconnect this equipment from the AC Mains, disconnect the power plug from the AC receptacle.
- The mains plug of the power supply cord shall remain readily operable.
WEEE Management: The symbol on the product or its packaging indicates that this product must not be treated as regular household waste. It must be disposed of by returning it to an authorized dealer.
Important Service Instructions
CAUTION: These servicing instructions are for use by qualified personnel only. To reduce the risk of electric shock, do not perform any servicing other than that contained in the Operating Instructions unless you are qualified to do so. Refer all servicing to qualified service personnel.
- Security regulations as stated in EN 60065 (VDE 0860 / IEC 65) and CSA E65 - 94 must be obeyed when servicing the appliance.
- Use of a mains separator transformer is mandatory during maintenance while the appliance is opened, needs to be operated, and is connected to the mains.
- Switch off the power before retrofitting any extensions, changing the mains voltage, or the output voltage.
- The minimum distance between parts carrying mains voltage and any accessible metal piece (metal enclosure), respectively between the mains poles, must be 3 mm and must be minded at all times. The minimum distance between parts carrying mains voltage and any switches or breakers that are not connected to the mains (secondary parts) must be 6 mm and must be minded at all times.
- Replacing special components marked with the security symbol (Note) in the circuit diagram is only permissible when using original parts.
- Altering the circuitry without prior consent or advice is not legitimate.
- Any work security regulations applicable at the location where the appliance is being serviced must be strictly obeyed. This also applies to any regulations about the workplace itself.
- All instructions concerning the handling of MOS circuits must be observed.
NOTE: SAFETY COMPONENT (MUST BE REPLACED BY ORIGINAL PART)
Description
Congratulations on your Electro-Voice PA series power amplifier purchase! The Electro-Voice PA-Series power amp line combines outstanding audio performance, exceptional reliability, and secure operational safety in a compact 2RU chassis design.
All models in the PA Series provide several protection circuits that prevent damage to the power amplifier and connected loudspeaker systems. These include Dynamic Audio Limiters, Inrush Current Limiter, Short Circuit Protection, and Thermal Overload Protection. All PA-Series power amps feature different hi-pass filters with switch-selectable cut-off frequencies to attenuate unwanted low-frequency signals.
Infinitely variable, low-noise, high-performance fans ensure absolute thermal stability while minimizing fan noise. The direct "flow-thru" chassis design allows for smooth front-to-rear airflow, enabling trouble-free operation even in smaller amp racks.
Compact, high-density power supply units with low-leakage toroidal transformers provide extensive headroom far above the listed power rating. Premium phoenix-style screw-lock connectors prevent accidental disconnection, ensuring a more secure connection of audio signal and speaker cables.
All PA series "T" version models are equipped with high-performance output transformers that also provide floating outputs for 50V, 70V, and 100V installations. These models also provide voltage limiters to protect the loudspeaker outputs against over-voltage.
Unpacking & Warranty
Carefully open the packaging and remove the power amplifier. The package includes this owner's manual, a mains cord, a warranty certificate, four attachable feet, and screw-lock connectors for all inputs and outputs. The warranty period is 36 months from the date of purchase from the dealer. Keep the original invoice and the warranty certificate in a safe place.
Installation Notes
Ensure the voltage selector on the amplifier's rear is set to the correct position matching the local mains voltage. Generally, power amplifiers should be installed to guarantee continuously unopposed front-to-rear air circulation. When installing in a closed cabinet or rack shelf system, ensure sufficient ventilation. Leave an air duct of at least 2.5" x 13" (up to the cabinet's top ventilation louvers) for air circulation between the rear of the power amplifier and the cabinet's/rack's rear wall. Ensure at least 4" of space above the cabinet or rack shelf system.
Temperatures inside a cabinet or rack shelf system can rise significantly during operation. Carefully consider the environmental temperature maximum values of all other appliances installed in the same rack shelf system (refer to "Mains Operation & Resulting Temperature").
When installing the power amp in a cabinet or rack shelf system, use the rear mounting facilities to fix the appliance and prevent the front panel from bending. If this is not possible, use mounting rails.
Caution: For problem-free operation, do not exceed the environmental temperature maximum of 105°F (40.5°C).
The power amplifier must be protected against: moisture (dripping or splashing water), direct sunlight, high temperatures or direct influence of heat sources, high humidity, extensive dust, and vibrations. Condensation on internal parts may occur after transporting the power amplifier from a cold to a warmer environment. In such cases, operation is only permissible after the appliance has reached the new temperature (after approximately one hour). If objects or liquids have entered the power amp's enclosure, disconnect the appliance from the mains immediately and contact an authorized service center for inspection before continuing to operate the unit.
Do not use sprays or solvents for cleaning the appliance, as they might damage the enclosure surface or create a fire hazard.
Front Panel
Mains Switch
Use the mains switch to turn the unit's power on. A soft-start function prevents inrush current peaks, preventing the mains line protection switch from activating during power-on. Loudspeaker outputs are activated via relay switching with a delay of approximately 2 seconds, eliminating potential power-on noise. The Protect LED lights during this delay to confirm correct operation of the protection circuitry.
Protect (PROT)
A lit Protect LED indicates that one of the integrated protections (thermal overload, short-circuit, etc.) has been activated. The protection circuits for the audio channels operate independently. In case of failure or overload, the affected power amp channel is disconnected from the load via an output relay, preventing damage to the connected loudspeakers and the power amplifier itself. The cause of the fault (e.g., a short-circuited speaker cable) must be remedied. In case of thermal overload, wait for the power amplifier to automatically return to normal operation.
Limiter
The Limit indicator lights when the integrated dynamic limiter is activated, indicating the power amp is driven at its clipping limit or maximum capacity. Short-term blinking is normal. If this LED lights constantly, it is strongly recommended to reduce the volume to prevent damage to the connected loudspeaker systems from potential overload.
Level Indication
The level indicators show the power amplifier's current modulation. The -30dB LED lights at approximately 30 dB below full modulation, and the -10 dB LED lights at approximately 10 dB below full modulation. Shorted speaker cables or the activation of a protection circuit will cause these indicators to go out.
Power
The Power indicator lights when the power amplifier is switched on. If the Power LED does not light, check the power connection or the primary fuse. If the fuse is blown, contact an authorized service center.
Rear Panel
Audio Signal Inputs
Electronically balanced inputs facilitate connecting external signal sources (e.g., mixing consoles). Screw-lock connectors prevent accidental disconnection when secured to the power amp. Balanced cables (2 conductors for audio signals + separate shielding mesh) are recommended for LF-signal connection, even if the source does not provide balanced output signals. This can be achieved by connecting the "-" conductor and shield together on the source side.
Level Controls
The Level Controls adjust the overall amplification of the respective power amp channel. To prevent distortion in connected mixing consoles, setting these controls between -6 dB and 0 dB is generally recommended. A scale indicates the varying additional control attenuation applied to the fixed internal amplification.
Mode Switch
The Mode Switch selects the power amp's operating mode. On four-channel models, channels A and B, or C and D, can be independently selected. Single-channel models do not have a mode switch.
- DUAL: Power amp channels operate independently, reproducing the audio signals fed to their respective inputs.
- PARALLEL: Both channels reproduce the audio signal fed to input A (or C). Level controls allow individual channel volume adjustment.
- BRIDGED (BDGD): Audio signals must be fed to channel A (or C). Channels A and B (or C and D) operate in push-pull, delivering doubled output voltage. Ensure correct loudspeaker connection for Bridged Mode operation.
High Pass Filter (HPF)
The Hi-Pass filter attenuates low bass audio signals. Three cut-off frequency settings are available:
| Power Amps with low impedance outputs | Power Amps with output transformer |
|---|---|
| 300 Hz, 12 dB/Oct., BW | 300 Hz, 12 dB/Oct., BW |
| 50 Hz, 12 dB/Oct., BW | 70 Hz, 12 dB/Oct., BW |
Models with an output transformer have a 50 Hz Hi-Pass filter in the audio signal path to protect the transformer from saturation by high-level low-frequency signals.
Loudspeaker Outputs
Speaker output jacks accommodate speaker cables up to 2.5 mm². Provided screw-lock connectors prevent inadvertent disconnection. Power amps offer low impedance outputs and/or floating outputs (ISOLATED OUTPUTS) with nominal voltages of 50V, 70V, and 100V, depending on the model.
Caution: The lightning flash symbol ⚡ at the loudspeaker connectors indicates high voltages that can cause serious harm. Connections at these outputs are only permissible for instructed personnel. Use prefabricated cables only.
PA2450L & PA4150L
Loudspeaker systems connected to channels A and B (or C and D) must be connected according to the indicated polarity. Mind the minimal impedance of 4 ohms per channel. For bridged operation, connect the load according to the BRIDGED label and set the Mode switch to "Bridged". In Bridged Mode, the minimal impedance is 8 ohms, and the input audio signal must be fed to channel A (or C).
PA1250T, PA2250T & PA2400T
Integrated audio output transformers convert the power amp's nominal output voltage to 50V, 70V, and 100V. Models PA2250T and PA2400T present all voltages simultaneously at the floating outputs, allowing mixed combinations of output voltages. Mixed operation of low-impedance speaker systems and floating loudspeaker lines on a single channel is also possible.
Using loudspeaker systems with 100V or 70V matching transformers is recommended when the distance between the power amp and speakers exceeds 165 feet to reduce cable loss effects and facilitate output power distribution. Connect as many loudspeaker systems as possible, ensuring the speaker network's total power consumption does not exceed the power amp's rated output power and does not fall below the nominal load impedance of the power amp outputs.
Mains Fuse
The mains fuse typically blows only in case of failure. When replacing the fuse, use one of the same type with identical amperage, voltage, and blow characteristics. If the mains fuse blows repeatedly, contact an authorized service center.
Mains Socket
Verify the voltage selector is set to the correct mains voltage for your installation site. An appropriate mains cord is included.
Caution: This appliance has no user-serviceable parts inside. Leave servicing to a qualified professional.
Voltage Selector
A sliding selector switch for switching between mains voltages 115V - 230V. Before switching mains voltage, replace the mains fuse with an appropriate model. Refer to the label on the rear of the enclosure for correct values for different mains voltages.
LF-Connection Cords
Balanced cables (two conductors for audio signals plus separate shielding mesh) are recommended for LF-signal connection. While unbalanced cables can be connected, balanced cables are always preferable. Many audio appliances feature balanced outputs via XLR-type connectors. With balanced cabling, the shield interconnects all metal enclosure parts, effectively eliminating external interference like noise and hum.
Mains Operation & Resulting Temperature
The following tables detail power supply and cabling requirements. The column "1/8 max. output power into 4 ohms" states values for normal operation, measured with the power amplifier at maximum output and a Pink Noise signal according to EN60065, approximating audio signal strain at maximum modulation.
Power drawn from the mains network is converted into acoustic output and heat. The difference between drawn and dispensed power is leakage power or dissipation (PD). Heat resulting from power dissipation may remain in a rack shelf and requires diversion through appropriate measures. The tables below aid in calculating temperatures inside a rack shelf system/cabinet and necessary ventilation efforts. The column "PD" lists leakage power for different operational states, and "BTU/hr" shows the dispensed heat amount per hour.
PA2450L
| Condition | Umains [V] | Imains [A] | Pmains [W] | Pout [W] | PD [W] | BTU/hr(3) |
|---|---|---|---|---|---|---|
| idle | 230 | 0.2 | 28 | 0 | 28 | 96 |
| Max. output power into 8Ω(1) | 230 | 5.4 | 923 | 2 x 300 | 323 | 1102 |
| Max. output power into 4Ω(1) | 230 | 8.8 | 1605 | 2 x 480 | 645 | 2201 |
| 1/3 max. output power into 4Ω(1) | 230 | 5.6 | 953 | 2 x 160 | 633 | 2160 |
| 1/8 max. output power into 4Ω(1) | 230 | 3.7 | 598 | 2 x 60 | 478 | 1631 |
| 1/8 max. output power into 4Ω(2) | 230 | 3.2 | 530 | 2 x 60 | 410 | 1399 |
| 1/8 max. output power into 4Ω(2)(4) | 253 | 3.6 | 629 | 2 x 73 | 484 | 1651 |
| Normal Mode (-10dB) into 4Ω(1) | 230 | 3.2 | 550 | 2 x 48 | 454 | 1549 |
| Rated output power (0dB, rated) into 4Ω(1) | 230 | 8.1 | 1482 | 2 x 450 | 582 | 1986 |
| Alert-Mode (-3dB) into 4Ω(1) | 230 | 6.1 | 1065 | 2 x 225 | 615 | 2098 |
PA4150L
| Condition | Umains [V] | Imains [A] | Pmains [W] | Pout [W] | PD [W] | BTU/hr(3) |
|---|---|---|---|---|---|---|
| idle | 230 | 0.4 | 54.7 | 0 | 55 | 187 |
| Max. output power into 8Ω(1) | 230 | 3.9 | 653 | 4 x 100 | 253 | 863 |
| Max. output power into 4Ω(1) | 230 | 6.3 | 1126 | 4 x 160 | 486 | 1658 |
| 1/3 max. output power into 4Ω(1) | 230 | 4.0 | 665 | 4 x 53 | 452 | 1541 |
| 1/8 max. output power into 4Ω(1) | 230 | 2.7 | 428 | 4 x 20 | 348 | 1187 |
| 1/8 max. output power into 4Ω(2) | 230 | 2.4 | 385 | 4 x 20 | 305 | 1041 |
| 1/8 max. output power into 4Ω(2)(4) | 253 | 2.6 | 450 | 4 x 24 | 353 | 1205 |
| Normal Mode (-10dB) into 4Ω(1) | 230 | 2.4 | 385 | 4 x 16 | 321 | 1095 |
| Rated output power (0dB, rated) into 4Ω(1) | 230 | 6.1 | 1080 | 4 x 150 | 490 | 1638 |
| Alert-Mode (-3dB) into 4Ω(1) | 230 | 4.6 | 790 | 4 x 75 | 490 | 1672 |
PA2400T - 100V output
| Condition | Umains [V] | Imains [A] | Pmains [W] | Pout [W] | PD [W] | BTU/hr(3) |
|---|---|---|---|---|---|---|
| idle | 230 | 0.3 | 44.3 | 0 | 44 | 151 |
| Max. output power into 25Ω(1) | 230 | 8.9 | 1643 | 2 x 430 | 783 | 2672 |
| 1/3 max. output power into 25Ω(1) | 230 | 5.5 | 952 | 2 x 143 | 665 | 2270 |
| 1/8 max. output power into 25Ω(1) | 230 | 3.7 | 602 | 2 x 54 | 495 | 1687 |
| 1/8 max. output power into 25Ω(2) | 230 | 3.3 | 545 | 2 x 54 | 438 | 1493 |
| 1/8 max. output power into 25Ω(2)(4) | 253 | 3.7 | 646 | 2 x 65 | 516 | 1760 |
| Normal-Mode (-10dB) into 25Ω(1) | 230 | 3.3 | 540 | 2 x 43 | 454 | 1549 |
| Rated output power (0dB, rated) into 25Ω(1) | 230 | 8.5 | 1550 | 2 x 400 | 750 | 2559 |
| Alert-Mode (-3dB) into 25Ω(1) | 230 | 6.3 | 1119 | 2 x 200 | 719 | 2453 |
PA2250T - 100V output
| Condition | Umains [V] | Imains [A] | Pmains [W] | Pout [W] | PD [W] | BTU/hr(3) |
|---|---|---|---|---|---|---|
| idle | 230 | 0.2 | 31.6 | 0 | 32 | 108 |
| Max. output power into 40Ω(1) | 230 | 5.5 | 960 | 2 x 270 | 420 | 1433 |
| 1/3 max. output power into 40Ω(1) | 230 | 3.5 | 571 | 2 x 90 | 391 | 1334 |
| 1/8 max. output power into 40Ω(1) | 230 | 2.3 | 365 | 2 x 34 | 298 | 1015 |
| 1/8 max. output power into 40Ω(2) | 230 | 2.1 | 330 | 2 x 34 | 263 | 896 |
| 1/8 max. output power into 40Ω(2)(4) | 253 | 2.3 | 385 | 2 x 41 | 303 | 1035 |
| Normal-Mode (-10dB) into 40Ω(1) | 230 | 2.1 | 328 | 2 x 27 | 274 | 935 |
| Rated output power (0dB, rated) into 40Ω(1) | 230 | 5.4 | 929 | 2 x 250 | 429 | 1464 |
| Alert-Mode (-3dB) into 40Ω(1) | 230 | 4.0 | 668 | 2 x 125 | 418 | 1426 |
PA1250T - 100V output
| Condition | Umains [V] | Imains [A] | Pmains [W] | Pout [W] | PD [W] | BTU/hr(3) |
|---|---|---|---|---|---|---|
| idle | 230 | 0.2 | 21.7 | 0 | 22 | 74 |
| Max. output power into 40Ω(1) | 230 | 2.8 | 487 | 1 x 270 | 217 | 740 |
| 1/3 max. output power into 40Ω(1) | 230 | 1.8 | 289 | 1 x 90 | 199 | 679 |
| 1/8 max. output power into 40Ω(1) | 230 | 1.2 | 182 | 1 x 34 | 148 | 506 |
| 1/8 max. output power into 40Ω(2) | 230 | 1.1 | 170 | 1 x 34 | 136 | 465 |
| 1/8 max. output power into 40Ω(2)(4) | 253 | 1.2 | 197 | 1 x 41 | 156 | 533 |
| Normal-Mode (-10dB) into 40Ω(1) | 230 | 1.1 | 164 | 1 x 27 | 137 | 467 |
| Rated output power (0dB, rated) into 40Ω(1) | 230 | 2.7 | 471 | 1 x 250 | 221 | 754 |
| Alert-Mode (-3dB) into 40Ω(1) | 230 | 2.0 | 339 | 1 x 125 | 214 | 730 |
(1) Sine wave 1 kHz
(2) Pink noise acc. to EN60065
(3) 1 BTU = 1055.06 J = 1055.06 Ws
(4) 10% mains over voltage
(5) PD = Power dissipation
The following factors allow direct proportional calculation of the mains current (Imains) for different mains supply voltages: 100V=2.3; 120V=1.9; 220V=1.05; 240V=0.96.
For power amp models with integrated transformers, the listed values for the 100V outputs are equally applicable for the 70V, 50V, and for the low-impedance outputs, provided the connected load is equivalent.
Technical Specifications
| Load Impedance | PA2450L | PA4150L | PA2400T | PA2250T |
|---|---|---|---|---|
| 8Ω | 4Ω | 8Ω | 4Ω | |
| Maximum midband output power THD=1%, 1kHz | 300W | 480W | 100W | 160W |
| Rated output power (°rated load) THD=0.2%, 20Hz ... 20kHz | 225W | 450W | 75W | 150W |
| Max. single channel output power Dynamic Headroom, IHF-A | 280W | 560W | 120W | 200W |
| Maximum bridged output power THD=1%, 1kHz | 900W | - | 315W | - |
| Maximum RMS voltage swing THD=1%, 1kHz | 44.7V | - | 32.1V | 44.7V |
| Voltage gain at 1kHz | 34.3dB | - | 30dB | 34.3dB |
| Slew rate at 1kHz | 28V/µs | - | 16V/µs | 25V/µs |
| Power consumption at 1/4 maximum output power, lim. pink | - | 530W | - | 360W |
| Input sensitivity at rated output power or voltage, 1kHz | 0dBu (775mV) | - | 0dBu (775mV) | 0dBu (775mV) |
| THD at rated output power MBW=80kHz, 1kHz | <0.1% | - | <0.1% | <0.1% |
| IMD-SMPTE 60Hz, 7kHz | <0.1% | - | <0.1% | <0.1% |
| DIM30 3.15kHz, 15kHz | <0.1% | - | <0.1% | <0.1% |
| Crosstalk ref. 1kHz, at 10% rated output power | <-75dB | - | <-75dB | <-75dB |
| Frequency response -1dB, ref. 1kHz | <10Hz - 40kHz | - | <10Hz - 40kHz | 65Hz - 40kHz |
| Power bandwidth THD=1%, ref. 1kHz, half power | <10Hz ... >50kHz | - | <10Hz ... >50kHz | 45Hz ... >20kHz |
| Input impedance 20Hz ... 20kHz, balanced | >20kΩ | - | >20kΩ | >20kΩ |
| Damping factor at 100Hz / 1kHz, 4Ω | >250 | - | >250 | - |
| Signal to noise ratio A-weighted | 104dB | - | 101dB | 103dB |
| Power requirements | 120V, 230V, 50Hz - 60Hz | - | 120V, 230V, 50Hz - 60Hz | 120V, 230V, 50Hz - 60Hz |
| Protection | Audio limiters, high temperature, peak current limiters, turn-on delay | - | Audio limiters, high temperature, peak current limiters, turn-on delay | Audio limiters, high temperature, peak current limiters, turn-on delay |
| Cooling | Front-to-rear | - | Front-to-rear | Front-to-rear |
| Safety class | - | - | - | - |
| Dimensions (W x H x D), mm | 483 x 88 x 405 (2RU) | - | 483 x 88 x 405 (2RU) | 483 x 88 x 405 (2RU) |
| Weight | 16.5kg (36.34lbs) | - | 18kg (39.65lbs) | 26kg (57.27lbs) |
Low impedance outputs:
- Minimum rated load for single channel operation is 4Ω. 2Ω load is not recommended.
- Minimum rated load for bridged operation is 8Ω. 4Ω load is not recommended.
Block Diagrams
Block diagrams illustrating the internal circuitry of the PA series amplifiers are provided for models PA4150L (Channels C/D), PA2450L, PA2400T, PA2250T, and PA1250T.
Dimensions
Diagrams showing the dimensions of the PA series amplifiers in millimeters are included.
