These are the results of the power and performance test conducted on the 7th April 2010 at the second Amplifier Meet in Peckham, London.
All power measurements are Maximum continuous output power in RMS watts* per channel, two channels driven to the threshold of clipping at 40 Hz, 1 kHz, and 10 kHz, and at loads of 8 ohm, 4 ohm and 2 ohm unless otherwise stated in the notes. Bridge power ratings are CALCULATED based on the amplifier's performance into 4R and 2R loads. 8R Bridge = 2 × 4R per channel; 4R Bridge = 2 × 2R Per channel. Inclusion of a calculated bridge rating does not necessarily mean the amp is bridgeable - PKN and Powersoft for example. "Continuous" means 5 seconds or greater - this ensured that the amplifiers were not damaged by the testing, and meant a sensible number of amplifiers could be tested in the alotted time. "Burst" (<100ms) ratings were not measured.
THD+N = Total Harmonic Distortion plus Noise and is a measure of the purity of the amplifier output as well as its noise level. It was measured at the maximum power output at various frequencies and load impedances. Anything below 1% is fine, below 0.1% is better. Obscure results sometimes appear because of distortion cancellation mechanisms.
Some amplifiers were not measured at 2R because they may have been damaged by the test. Exclusion of a 2R measurement does not mean the amplifier will not withstand 2R LOUDSPEAKER loading. Sine testing into a dummy load is considerably more demanding of an amplifier.
All tests were carried out using a Bruel & Kjaer 1023 Sine wave oscillator, HP8903A Audio distortion analyser, an HP3456A true-RMS digital voltmeter, a 8/4/2R Resistive dummy load, and a Tektronix TDS210 Digital Realtime Oscilloscope.
All amplifiers were fed from the same supply, adapted according to the mains plug fitted. 32A, 16A and 13A was available.
The mains voltage was not measured on the day. This fact has caused considerable debate on internet forums and may account for the fact that some manufacturers' amplifiers performed below their stated specification. Despite the central London location of the test, the mains voltage may have been lower than normal which can affect the maximum power obtainable from an amplifier, especially toroidal and non-PFC SMPS amplifiers. We implemented mains-voltage measurements at amp meet three. We would welcome the opportunity to repeat these tests in a more tightly controlled environment in our lab. Please get in touch with us if you would like to send us an amplifier to test.
In no particular order:
Manufacturer | Model | Freq | 8 Ohm Performance | 4 Ohm Performance | 2 Ohm Performance | 8R Bridge Watts (Calc) | 4R Bridge Watts (Calc) | Notes |
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Watts | THD+N | Watts | THD+N | Watts | THD+N | ||||||
Labgruppen COPY | FP10000Q | 40 Hz | 1282 | 0.18% | 1968 | 0.25% | 880 | 3937 | 1761 | Severe oscillation on top half of waveform at 2R. Amplifier
buggered at 2R 40Hz. Inadequate protection. 4 channel amp, two channels
driven |
|
1 kHz | |||||||||||
10 kHz | |||||||||||
Crown | IT8000 | 40 Hz | 1006 | 0.90% | 492 | 1.00% | 984 | Thermal Limit at 40Hz 4R. Amplifier protecting
itself against too much mains current draw. 1kHz 4R power should be
considered a burst rating. |
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1 kHz | 2026 | 0.12% | 3930 | 0.15% | 7860 | ||||||
10 kHz | 2411 | 0.70% | 2467 | 0.90% | 4934 | ||||||
QSC | PL236 | 40 Hz | 737 | 0.07% | 1133 | 0.13% | 2266 | Filters Disabled, remained cold |
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1 kHz | 744 | 0.16% | 1239 | 0.40% | 2479 | ||||||
10 kHz | 755 | 0.60% | 1172 | 0.90% | 2345 | ||||||
QSC | MX3000A | 40 Hz | 820 | 0.07% | 1273 | 0.10% | 2547 | Amp remained cold throughout |
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1 kHz | 788 | 0.07% | 1263 | 0.30% | 2526 | ||||||
10 kHz | 726 | 0.07% | 1172 | 0.09% | 2345 | ||||||
MC2 | E25 | 40 Hz | 603 | 1075 | 2151 | One channel
Faulty, ONE CHANNEL DRIVEN. Severe crossover distortion at 10K, possible fault on working channel. Unable to
measure THD because of floating grounded output. |
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1 kHz | 603 | 1001 | 2002 | ||||||||
10 kHz | 586 | 1013 | 2026 | ||||||||
MC2 | E45 | 40 Hz | 900 | 1511 | 2912 | 3022 | 5824 | ONE CHANNEL DRIVEN at 2R. Unable to measure THD because of
floating grounded output |
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1 kHz | 921 | 1515 | 2772 | 3029 | 5544 | ||||||
10 kHz | 744 | 1308 | 2469 | 2616 | 4937 | ||||||
Void | Inf 7 Mk 1 | 40 Hz | 952 | 0.30% | 1451 | 0.50% | 2903 | Not tested at 10kHz because the amp probably
wouldn't have survived it. |
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1 kHz | 952 | 0.50% | 1526 | 0.80% | 3052 | ||||||
10 kHz | |||||||||||
Void | Inf 8 Mk 2 | 40 Hz | 1234 | 0.10% | 2099 | 0.14% | 4198 | Powered from 32A
Cee-Form. Peak draw according to front panel ammeter was 47A |
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1 kHz | 1234 | 0.13% | 2099 | 0.28% | 2608 | 4198 | 5215 | ||||
10 kHz | 1234 | 0.30% | |||||||||
Labgruppen | LAB4000 | 40 Hz | 1140 | 0.10% | 1273 | 0.08% | 2547 | 9 years old - csg asked me to note this |
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1 kHz | 1186 | 0.40% | 1172 | 0.05% | 824 | 0.06% | 2345 | 1648 | |||
10 kHz | 1094 | 0.40% | 1169 | 0.40% | 2338 | ||||||
MC2 | Turbosound 1250 | 40 Hz | 668 | 0.11% | 1169 | 0.10% | 1148 | 0.18% | 2338 | 2296 | Bad high
frequency artefacts when clipping at 10kHz. |
1 kHz | 599 | 0.05% | 1085 | 0.08% | 1139 | 0.22% | 2170 | 2277 | |||
10 kHz | 611 | 0.05% | 1104 | 0.20% | 1034 | 0.50% | 2208 | 2068 | |||
Peavey | PV2600 | 40 Hz | 586 | 0.05% | 923 | 0.80% | 1846 | Excellent clipping and limiting behaviour |
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1 kHz | 558 | 0.04% | 923 | 0.60% | 1263 | 0.70% | 1846 | 2526 | |||
10 kHz | 563 | 0.09% | 818 | 0.09% | 1636 | ||||||
Matrix | 2U Matrix Short (Unlabeled) | 40 Hz | 213 | 0.10% | 269 | 0.20% | 538 | Amp remained cold
throughout |
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1 kHz | 205 | 0.09% | 285 | 0.25% | 570 | ||||||
10 kHz | 195 | 0.20% | 283 | 0.50% | 567 | ||||||
Matrix | 2U Matrix Long (Unlabeled) | 40 Hz | 433 | 0.10% | 772 | 0.20% | 1543 | Amp remained cold throughout |
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1 kHz | 476 | 0.50% | 782 | 0.60% | 1565 | ||||||
10 kHz | 433 | 0.20% | 703 | 0.30% | 1407 | ||||||
Matrix | 1U Short (Unlabeled) | 40 Hz | 230 | 0.20% | 318 | 0.30% | 637 | ||||
1 kHz | 221 | 0.20% | 312 | 0.30% | 623 | ||||||
10 kHz | 211 | 0.10% | 295 | 0.19% | 589 | ||||||
Matrix | XP3000 Toroidal | 40 Hz | 824 | 0.11% | 1159 | 0.23% | 1205 | 0.60% | 2318 | 2410 | |
1 kHz | 763 | 0.10% | 1120 | 0.22% | 1333 | 0.60% | 2240 | 2665 | |||
10 kHz | 755 | 0.80% | 944 | 1.60% | 1887 | ||||||
Matrix | Vector 350 Toroidal | 40 Hz | 101 | 0.10% | 107 | 0.20% | 213 | ||||
1 kHz | 89 | 0.13% | 113 | 0.22% | 225 | ||||||
10 kHz | 89 | 0.50% | 95 | 0.70% | 190 | ||||||
Matrix | XP5000 Switched Mode | 40 Hz | 915 | 0.80% | 1069 | 1.60% | 2138 | One channel driven at 2R due to power supply over-temperature issues. Limited power due to limiter action, which, even though disengaged, caused limiting at 4R |
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1 kHz | 888 | 0.70% | 1140 | 2.00% | 1547 | 1.10% | 2279 | 3094 | |||
10 kHz | 860 | 1.20% | 1082 | 2.70% | 2163 | ||||||
Matrix | XP5000 Switched Mode, sample 2 | 40 Hz | 946 | 1.20% | 1393 | 2.10% | 2786 | Both Channels
Driven 2R - earlier version without power supply over temperature protection. Compare 2R figure above |
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1 kHz | 820 | 1.20% | 1354 | 2.00% | 1097 | 3.00% | 2708 | 2194 | |||
10 kHz | 854 | 1.20% | 1219 | 2.10% | 2438 | ||||||
Crown | XTI4000 | 40 Hz | 680 | 0.30% | 1019 | 0.30% | 2038 | DSP system disabled. 180 degree phase shift between input and
output at 10kHz due to ADC/DAC anti-aliasing filters |
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1 kHz | 689 | 0.12% | 854 | 0.24% | 1708 | ||||||
10 kHz | 594 | 0.50% | 914 | 0.26% | 1829 | ||||||
QSC | PLX3402 | 40 Hz | 757 | 0.10% | 1156 | 0.50% | 2312 | Good clipping and
limiting behaviour |
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1 kHz | 748 | 0.13% | 1222 | 0.20% | 2445 | ||||||
10 kHz | 707 | 0.05% | 1216 | 0.20% | 2431 | ||||||
Labgruppen | LAB1000 | 40 Hz | 430 | 0.50% | 686 | 1.00% | 1371 | Not switched-mode |
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1 kHz | 403 | 0.30% | 656 | 0.30% | 1311 | ||||||
10 kHz | 399 | 0.30% | 651 | 0.50% | 1302 | ||||||
Labgruppen | LAB1200C | 40 Hz | 339 | 0.05% | 641 | 0.50% | 1282 | Excellent clipping and limiting behaviour |
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1 kHz | 340 | 0.04% | 617 | 0.06% | 1234 | ||||||
10 kHz | 338 | 0.06% | 617 | 0.30% | 1234 | ||||||
Labgruppen | LAB1600 | 40 Hz | 412 | 0.40% | 756 | 0.17% | 1511 | Excellent clipping and limiting behaviour |
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1 kHz | 405 | 0.60% | 756 | 0.40% | 1511 | ||||||
10 kHz | 413 | 1.10% | 703 | 0.14% | 1407 |
* "RMS Watts" is technically an incorrect term: see http://www.epanorama.net/documents/audio/amplifier_power.html