Yamaha P-series Professional Power Amplifiers P2150
The dual-channel amplifier shall include a rear-panel switch that converts the amplifier to monaural operation, in which case the bridged outputs shall deliver maximum continuous sine wave power output over a 20 Hz to 20 kHz bandwidth of (300 watts, 500 watts) into a minimum 8 ohm load impedance, or (220 watts, 340 watts) into a 16 ohm load with no more than 0,05% thd s/n in bridge mono mode, as established by comparing the maximum output with signal to the minimum output noise with a shorted input, shall be no less than 106 dB measured with a _6 dB/octave low pass filter at 12,47 kHz (equal to a “brick wall” filter at 20 kHz), and no less than 115 dB measured with an IHF “A” weighting network. Channel separation shall be at least 90 db at 1 khz, and shall be at least 70 db at any frequency from 20 Hz to 20 kHz. Slew rate in bridged mono mode shall be at least 90 volts per microsecond, full swing.
Single and Dual –Channel Models in Two Power Ranges
the P1150 is a single channel amplifier rated at 100 watts into 8 ohm or 150 watts into 4 ohm; the dual-channel P2150 delivers the same power output per channel, the P1250 is a single channel amplifier rated at 170 watts into 8 ohm or 250 watts into 4 ohm, the dual-channel P2250 delivers the same power output per channel.
A rear panel switch on both dual-channel models rewires them internally for use in a bridged , MONO (single-channel) configuration; in this mode the P1250 delivers 200 watts into 16 ohm or 300 watts into 8 ohm, and the P2250 delivers 340 watts into 16 ohm or 500 watts into 4 ohm.
by using both channels of a dual-channel model to drive a single speaker load in the bridged (mono) configuration, it is possible to achieve the wide headroom and dynamic range needed for accurate reproduction of peaks and transient sounds. The P2250 in bridged Mono mode, will deliver 63 volts to the speaker line and therefore may be used to drive a slightly de-rated 70 volt line (for use with a distributed speaker system)
Multiple Protection Techniques Avoid Damaged Speakers
theoretically , a power amplifier is capable of damaging speakers in many ways. The new Yamaha professional amps are designed to eliminate as many potential damage modes as is practical without causing unwanted shut-down or impairment of the sound.
A turn-on transient (a low frequency “thump”) may occur as the power supplies in mixers, console or auxiliary signal processing equipment activate their internal circuits. One does not want these “thumps” to be amplified by the power amp. Or speaker damage might occur. The safest approach here is to disconnect the speakers from the amplifier until all equipment in the sound system has stabilized. That’s why we designed these amplifiers with a relay that disconnects the output until after power has been on a few seconds. This protection is only effective, however, with good operating practice – i.e., if you turn on the amplifier Last – after first turning on the console, electronic crossover, and any signal processing equipment.
If DC were to appear at an amplifier’s output, it would cause speaker voice coils to move to one position and stay there, which can quickly lead to voice coil overheating and premature failure of the speaker. Even relatively low levels of DC can cause this problem, DC can appear at a direct coupled amplifier’s output when the input signal has just a few millivolts of DC offset. That’s the advantage of AC coupled amplifiers such as these. Still, it is conceivable that some DC might appear at the output of an AC-coupled amplifier in the presence of asymmetrical, very low frequency input signals. In any event, high DC levels, as might be caused by a short between the power supply “ralls” and the output , can instantly destroy a speaker or compression driver. To prevent any such catastrophe circuitry in these amplifiers senses the presence of any significant DC component at the output(more than 2 volts), and opens the speaker relay immediately, when this occurs, the front-panel Protection LED turns on. Given that the average 8 ohm speaker has a DC resistance of about 5 ohms, this means that the relay would shut down the output before so much as 1 watt of DC power reached the speaker load.
If a short circuit in the speaker or cable or a very low impedance speaker load overloads the amplifier, current limiting circuitry in the amplifier prevents excessive power from being delivered to the load.
Features
Every effort has been made to provide the features that musicians, soundmen and engineers feel they need in a professional power amplifier. Rather than experiment with exotic designs, we have applied field-proven principles to design amplifiers which are highly stable, and will deliver the kind of reliability enjoyed for over a decade by Yamaha professional and commercial sound products.
Recessed input attenuators with 32 calibrated, detented positions are easily operated. To discourage casual tampering, rubber security covers are included.
Electronically balanced, differential input circuits allow the use of long, shielded 3-wire input cables to reduce susceptibility to hum.
Two methods to connect each input: XLRs combine the advantages of electrostatic and electromagnetic noise rejection, with locking terminals that won’t pull out accidentally should the cable be tugged. Phone jacks provide for fast, compatible connection to equipment that utilizes phone jacks instead of one per channel, we have made it easier to “daisy chain” connect more than one amplifier to a given signal source – on “Y” adapter cable is required.
The output circuitry is fully protected from overloads and short circuits, and the speaker outputs are relay-protected against turn-on transients and DC offset.
five-way binding post output connections provide more secure wiring, better current handling capability, and less tendency to built up contact resistance than typical phone jack outputs. Phone jack outputs are provided for convenience in fast setup situations.
Rated for 4-ohm or higher impedance loads
P2250, in bridged mono mode , can drive 70-volt lins without an output transformer.
Two-stage, temperature-operated cooling fan pulls air through a front panel filter to keep the power transformer and heat sinks cool, further protection afforded by a thermal breaker.
Convenient power cord holders on rear panel enable amp to be set “on end” without damage to connectors; sturdy front panel handles for easy removal from rack and more comfortable carrying.
Well suited to a variety of sound reinforcement, recording and musical instrument applications.
Specifications P2150
Power Output Level (THD =0,05%)
Stereo
20 Hz – 20 kHz : 100 W + 100 W (at 8 Ω ); 150 W + 150 W (at 4 Ω )
1 kHz: 105 W + 105 W (at 8 Ω ); 165 W +165 W (at 4 Ω )
BTL-Mono
20 Hz – 20 kHz : 220 W (at 16 Ω ); 300 W (at 8 Ω )
1 kHz: 250 W (at 16 ohm); 330 W (at 8 ohm
Frequency Response: 10 Hz – 50,000 Hz (8 Ω ) +0 -1 dB
Power Bandwidth (THD =0,1%)
Stereo
10 Hz to 50,000 Hz (55 W) at 8 Ω
10 Hz to 50,000 Hz (75 W) at 4 Ω
BTL-Mono
10 Hz to 50,000 Hz (110 W) at 16 Ω
10 Hz to 50,000 Hz (150 W) at 8 Ω
Total harmonic Distortion:
Stereo
Less than 0,007% ( 55 W, 20 Hz – 20 kHz, 8 Ω )
Less than 0,003% ( 55 W, 1 kHz, 8 Ω )
Less than 0,005% ( 75 W, 1 kHz, 4 Ω )
Less than 0,01% ( 75 W, 20 Hz – 20 kHz, 4 Ω )
BTL-Mono
Less than 0,007% ( 110 W, 20 Hz – 20 kHz, 16 Ω )
Less than 0,003% ( 110 W, 1 kHz, 16 Ω )
Less than 0,005% ( 150 W, 1 kHz, 8 Ω )
Less than 0,01% ( 150 W, 20 Hz – 20 kHz, 8 Ω )
Intermodulation Distortion (60 Hz : 7 kHz = 4:1)
Stereo
less than 0,005% (55 W, 8 Ω )
less than 0,01% (75 W, 4 Ω )
BTL-Mono
less than 0,01% (150 W, 8 Ω )
less than 0,01% (110 W, 16 Ω )
Damping Factor
Better than 110 (1 kHz , 8 Ω ); >55 (1 kHz , 4 Ω )
Signal-to-Noise-Ratio:
Stereo
Better than 110 dB (Input Short; at 12,47 kHz, -6 dB/octave LPF)
Better than 115 dB (Input Short, IHF A Network)
BTL-Mono
Better than 106 dB (Input Short; at 12,47 kHz, -6 dB/octave LPF)
Better than 110 dB (Input Short, IHF A Network)
Slew Rate
Stereo : ± 50 V/µsec (8 ohm, Full Swing)
BTL-Mono : ±90 V/µsec (16 Ω , Full Swing)
Sensitivity : +4 dB (1,23 V rms) for nominal output (4 Ω load)
Voltage Gain: 26,0 dB
Input Impedance: better than 15 k Ω , Balanced or Unbalanced (Att. Max)
Residual Noise (Input Att. Minimum)
Less than -80 dBm, -6 dB/oct. LPF at 12,47 kHz
Less than -90 dBm, IHF A network
Indicators
Signal: Green LED(-20 Hz to 20 kHz, Vo better than 2 V
Clipping: Red LED Total harmonic Distortion: better than 1%
Protection: Red LED (during the protection or muting is on)
Pilot: Red LED Power ON
Protection Circuits
Muting: 6 ± 2sec After Power ON
DC Sense: DC ±2 sec. Ouptut Voltage
Thermal: better than 85°C Heat sink temperature
PC Limiter: ON RL less than 2 Ω
FAN Circuit
Better than 60°C High speed run, Heat sink temperature
Less than 45°C Restoration of a low speed run, Heat sink temperature
Front Controls: 2 x 32 step Input Attenuator (0 to -20 dB in 1 dB steps, -20 to -30 dB in 2 dB steps, then -33, -37, -42, -50, -60 dB, and infinite attenuation
Push ON/Push Off Power Switch
Rear Control: Mono/Stereo Mode Switch
Power Requirements
220/240 V AC 50/60 Hz (General model) 120 V AC, 60 Hz (US and Canada models)
Power Consumption
800 W (General mode); 500 W, 600 VA (US and Canada model)
dimensions (W x H x D): 480 x 132 x 423 MM (18-7/8” x 5-1/4” x 16-5/8”)
Weight: 17 kg (37,4 lbs)
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