Accuphase PS 1210 Brochure

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The Clean Power Supply components from Accuphase are revolutionary products that remove noise and impurities from the AC power line and improve signal quality by continually monitoring and shaping the power supply waveform. They have been widely acclaimed for drastically improving the sound and picture quality of audio and video equipment. The PS-1210 is an upgraded version that incorporates the latest MCS+ circuit topology in the waveform compensation amplifier section. The reference signal generator features further improved accuracy to assure the lowest possible distortion in the output waveform. Because the PS-1210 can deliver as much as 1200 VA (230 V AC version) or 1000 VA (120 V AC version), it covers the requirements of almost any high-quality A/V system currently on the market. AC LINE POWER 0 10k 20k [Hz] -100.0-75.0 -50.0 -25.00.0 [dB]PS-1210 OUTPUT POWER 0 10k 20k [Hz] -100.0-75.0 -50.0 -25.00.0 [dB] 50Hz 50Hz Line filterMeter selector Alarm indication circuit Adding/sub- tracting circuit Wavefor m compensation amplifier Error detector Wavefor m comparator Reference signal generator Rectifier Meter The PS-1210 uses waveform shaping technology to turn the power from a regular AC outlet into a highly pure sine waveform for use as a stable and uncontaminated energy source of A/V components. To achieve this, the PS-1210 takes the power source waveform and compares it to a highly accurate and stable reference waveform. Based on this comparison, it then adds or subtracts exactly the required amount of correction. The compensation required by this innovative technique typically is only a fraction of overall power. The PS-1210 therefore operates with high efficiency and produces little heat, allowing it to be designed as a fairly compact and lightweight unit. Since all circuitry is analog and there are no oscillators or switches, the PS-1210 itself does not act as a source of spurious high-frequency noise. Power Supply Waveform and Clean PS-1210 Output Waveform Almost all electrical devices used in a household convert the AC supplied by the outlet into direct current for powering internal circuits. This task is performed by a rectifier. As shown in photograph a, the rectifier load current has a pulse waveform with a large current flowing momentarily in the vicinity of the voltage peak. This causes a voltage drop, resulting in clipping of the voltage waveform, as shown in photograph b. A clipped waveform with a high amount of distortion contains many unwanted frequency components, or harmonics, as shown below. When entering the audio circuitry of an amplifier through the power supply, such harmonic components can interfere with the audio signal and cause intermodulation distortion, which has a highly detrimental effect on sound quality. When passing through the PS-1210, the deformed waveform is restored to its original sine wave pattern (see frequency spectrum in the graph below). The result is a clean sine waveform as shown in photograph c. Photo a Current waveform of rectified load Photo b Voltage waveform of AC line (distortion approx. 3%) Photo c PS-1210 output waveform (distortion approx. 0.2%) Fig. 1 Operation Block Diagram of PS-1210 AC Voltage Stabilizer Based on Waveform Shaping Technology The PS-1210 accepts AC power on the input side, processes it using internal control circuitry, and supplies it as clean AC power on the output side. Most of the AC energy from the input is carried over to the output. The loss introduced by the PS-1210 is very small, since it consists only of the power re- quired for waveform compensation. As shown in Figure 1, the signal from the secondary winding S 1 of the transformer reaches the adding/sub- tracting circuit and appears at the output as output voltage (e 0). The S 2 signal from the transformer goes to the ref- erence signal generating cir- cuit where it becomes the high-precision sine waveform (e i) synchronized to the input frequency of 50/60 Hz. This reference sine wave (e i) is then used as reference signal to be compared to the output voltage. The differential component is extracted and used by the adding/ subtracting circuit to provide exactly the required amount of compensation for turning the output into a high- precision sine waveform. Highly Effective Interference Rejection The input side of the PS-1210 is equipped with a line filter for removing any high-frequency noise components present in the power line, such as generated by digital equipment. The primary and secondary windings of the power transformer are kept totally separate, and the fully shielded design shuts out any externally induced noise. Since the amplifier uses the feedback principle, output impedance is extremely low. This prevents any possibility of mutual interference between components connected to the outputs of the PS-1210. Built-in Meter Allows Monitoring of 5 Parameters: Output Power, Input/Output Voltage, Input/Output Distortion The meter of the PS-1210 lets the user see at a glance how much power (VA) the connected equipment is consuming at any given time. This is especially helpful for components such as integrated amplifiers or power amplifiers whose power consumption differs considerably depending on the volume setting and actual music signal. When the maximum rated output power (1200 VA) is exceeded, the meter illumination flashes as a warning indication. 400 600 200 0 [%]0.8 0.6 0.4 0.2 800 1000 1200 400 600 200 0 1800 1600 1400 1200 1000 800 600 400 200 [ VA] [%] 80 60 40 20 800 1000 1200 Efficiency Input/output power Effi- ciencyInput power THDOutput power [VA] Output power [VA] Output power/input power (efficiency) characteristics Output power/THD characteristics Assembly with input voltage/ distortion monitoring circuitry Meter of 230 V AC version Fig. 2 PS-1210 Load Characteristics Frequency spectrum of power line Frequency spectrum of power line (photo b bb b b) Frequency spectrum of PS-1210 output (photo c cc c c) Tap into a totally clean source of AC energy -“ Revolutionary waveform shaping technology enables highly precise compensation, creating a pure energy source of 230 V AC (or 120 V AC) ±2 % with max. 0.22 % THD. Connect audio or video equipment for a drastic improvement in sound and picture quality. Monitor output power (VA), input/output voltage (V), and input/output distortion ( % ) on the built-in meter.

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14.1 V 14.1 V +170/ 325 V +14.1 V00 -14.1 V t t 14.1 V 14.1 V +14.1V0 0-14.1V t t [50 Hz] [60 Hz] From secondary winding of power transformerSquare wave generator Bandpass filter Bandpass filterBand-stop filter Band-stop filterBandpass filter Reference output waveform PS-1210 230/120 V AC output waveform 220/120 V AC input waveform Compensation waveformCompensation waveform PS-1210 230/120 V AC output waveform240/130 V AC input waveform -170 / 325 V +170/ 325 V -170/ 325 V Compensation Amplifier Based on High-Precision Reference Signal Creates Pure 230 V (or 120 V) AC Source -–  -– -–  -–  -– Low-Distortion Reference Signal GeneratorThe waveform of the signal detected at the S 2 winding of the power transformer (see Fig. 1) is used by a highly precise Zener diode circuit to generate a square waveform. A newly developed 50/60 Hz bandpass filter and band-stop filter are then applied to the waveform. The filter frequency is switched in sync with the input frequency, for automatic 50 Hz and 60 Hz support. By routing the signal through another bandpass filter, a low-distortion sine wave (reference signal) is created that is not dependent on the input voltage. -–  -– -–  -–  -– Superior Waveform Compensating PowerWhen the input voltage is 220 V (110 V), the voltage at the secondary side of the transformer will also be 220 V (110 V). To bring this to 230 V (120 V), 10 volts must be added, as shown in Figure (a). Conversely, if the input is 240 V (130 V), 10 volts must be subtracted to yield 230 V (120 V), as shown in Figure (b). (As the figures show, in actual operation, the peak value of 10 V, namely 14.1 V, is added or subtracted.) The sine wave (e i) synchronized to the input frequency and the output voltage (e o) are compared, and for any excessive or missing component, a compen- sation waveform up to a maximum of ±10 V (peak value ±14.1 V) is gener- ated and imposed on the output voltage. Conse- quently, for an input volt- age range of 200-253 V AC (108-132 V AC) at the rated load of 1200 VA (1000 VA), the output voltage is kept cons tant at 230 V ±2% (120 V ±2 %), with a maximum dis- tortion ratio of 0.22%. These values demon- strate the outstanding waveform compensation ability of the PS-1210. Reference Signal Generator Block Diagram Excellent Current Capability The power amplifier which performs waveform compensation uses the current feedback principle for excellent high-frequency phase characteristics and operation stability. This is combined with the MCS+ circuit renowned for superior performance and sound quality. The output stage uses 20 transistors rated for a maximum current of 15 amperes. These devices are connected in a parallel complementary push-pull arrangement which boasts a rated output current of 5.2 A (8.3 A) and an instantaneous peak current (inrush current) rating of 60 A (120 A). This demonstrates the excellent current capability of the PS-1210. bAssembly with waveform compensation amplifier for addition/subtraction, output stage with 20 parallel push-pull power transistors mounted to two large heat sinks, waveform compensation amplifier, etc. Note: The explanation is for the 230 V AC version of the PS-1210. Figures in brackets refer to the 120 V AC version. Waveform Shaping Principle of PS-1210 (a) If power source voltage is lower than 230 V (120 V), addition is performed(b) If power source voltage is higher than 230 V (120 V), subtraction is performed The photograph shows the 230 V version. -–  -–  -–  -–  -–  Assembly with reference signal generator and other circuitry