回复人: | 鹤城老黄 | 来 自: | 221.209.15.2 |
回复时间:: | 2007-04-06 10:00:09 | 讨论 | 返回本版 |
评述: | Freq. Response
Power Output Distortion Output Impedance Input Impedance Input CMRR Power Consumption Dimensions Shipping Weight 20 dB balanced 20 or 26 dB unbalanced - 3 dB at 100 kHz 200 watts @ 8 ohms < 1 % THD approx. .1 ohm 10 Kohm > -60 dB 500 watts 16.5 \" W x 16.5 \" D x 10.5\" H 130 lb. |
回复人: | 鹤城老黄 | 来 自: | 221.209.15.2 |
回复时间:: | 2007-04-06 09:58:06 | 讨论 | 返回本版 |
评述: | 比尔你好!!!PASS的资料我找到了!!谢谢你帮我找个好前级
REVIEWS/AWARDS PROJECTS/ARTICLES Q&A LINKS DEALERS HOME Aleph 1.2 Power Amplifier Picture of the Aleph 1.2 Aleph 1.2 Owner's Manual The Aleph 1.2 is the largest amplifier from Pass Laboratories and expands upon the vision of pure high power, idling at 500 watts and delivering 200 watts in single-ended Class A. Single-ended Class operation is often referred to as the "king of Class A" because it has the smoothest transfer curve and operates at the lowest efficiency of the family of Class A topologies. Properly designed, a single- ended amplifier exhibits second and even order harmonic structure, similar to the transfer characteristic of air, where the phase of the signal and harmonics reflects the subtle difference between acoustic compression and rarefaction. The price paid for this performance is in high idle current and dissipation, generally three to five times the output rating. The Aleph 1.2 conforms to the Pass philosophy of having absolutely minimal parts in series with the signal path. The input signal travels through a resistor to the input Mosfet transistor, and from there through another resistor to the parallel output Mosfets, and from there through a power resistor to the loudspeaker. There are only two sets of gain devices and three resistors between the input and output. This minimalist topology is supported outside of the signal path by regulated current sources which separately bias the input and output stages. The Aleph 1.2 is unlike the original Aleph 1 in two important ways. First, it has only two gain stages instead of the original three. With one less gain stage, there is less information lost within gain devices and in feedback. There is improved intimacy between the input and output, resulting in greater immediacy, detail, warmth, and depth. The amplifier also does not have the auxiliary pull circuitry which allowed the Aleph 1 to deliver very high currents into low impedance loads. This is a purer approach, however it does not allow for greater power below 4 ohms. The amplifier will drive and is stable into any load impedance or reactance including a direct short, and delivers clean audio into very tough loads. The current source which biases the output stage is a new design which maximizes the performance of the output stage into reactive loads. It helps to optimize the load-line of the single-ended output devices, lowering distortion. The design of this current source is protected by US patent application. The Aleph 1.2 uses power Mosfets for both gain stages. These Mosfets were chosen because they have the most ideal transfer curve for an single-ended Class A design. Mosfets also allow high current operation with low circuit complexity, delivering high performance in a minimalist topology. The input P channel and output N channel Mosfets are carefully selected from the same manufacturing lot codes and matched to a tolerance of 2%. Precision metal film resistors are used throughout. The Aleph 1.2 has been designed for maximum reliability and years of trouble free operation. The input gain devices are pulse rated 8 amps and are followed by output devices with pulse ratings of 50 amps each. The amplifier employs 3.6 kilowatts of power Mosfet output devices and massive heat sinking rated at .05 degree per watt. During active operation the amplifier consumes 500 watts, so that each output device is operated at 14% of its rated power. The Aleph 1.2 is protected from overheating by a 75 degree C. thermal switch, and from internal failure by a slow-blow fuse. The amplifier is powered by a toroidal transformer rated at 10 times the amplifier's output rating which charges 100,000 uF of supply capacitance to 500 Joules. This unregulated supply feeds the output transistors with a full power ripple of about 1/2 volt. The amplifier is equipped with a balanced input featuring a common mode input noise rejection of -60 dB, accomplished through a passive network tied directly into the input stage of the amplifier, not with additional active input circuitry. Unbalanced input is accommodated through RCA connectors. The ultra-high bias current, the transconductance character of the Mosfets, and the simple design topology all combine to deliver an amplifier having high power and strong "bench" performance while still delivering the emotionally involving warmth and depth associated with the finest tube amplifiers. The sound of the Aleph amplifiers has been recognized world-wide as the most natural obtainable from solid state amplifiers. SPECIFICATIONS Gain Freq. Response Power Output Distortion Output Impedance Input Impedance Input CMRR Power Consumption Dimensions Shipping Weight 20 dB balanced 20 or 26 dB unbalanced - 3 dB at 100 kHz 200 watts @ 8 ohms < 1 % THD approx. .1 ohm 10 Kohm > -60 dB 500 watts 16.5 " W x 16.5 " D x 10.5" H 130 lb. |