Accuphase PS 1200 V Brochure

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Tap into a totally clean source of AC energy, free from distortion and high-frequency noise. Revolutionary waveform shaping technology enables highly precise compensation, providing a pure energy source with 230 V AC ±2% (or 120 V AC ±2%). Connect audio or video equipment for a drastic improvement in sound and picture quality. Monitor output power, input/output voltage, and input/output distortion on the built-in meter. Almost every electrical device used in an household converts the AC supplied by the outlet into a DC current for powering its internal circuits. This task is performed by a rectifier. As shown in photograph , 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 . A clipped waveform with a high amount of distortion contains many unwanted frequency components, or harmonics. When passing through the PS-1200V, the deformed waveform is restored to its original sine wave pattern, as shown in photograph . Photo Current waveform of rectified load Photo Voltage waveform of AC line (distortion approx. 3%) Photo PS-1200V output wave- form (distortion approx. 0.2%) Power supply waveform and PS-1200V output waveform 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-1200V is a further upgraded version of the predecessor model PS- 1200. The circuitry has been optimized to fulfilleven higher performance demands, and the power transformer that forms the heart of the system is now a high-performance type with even more muscle. Because the PS-1200V is a high-power version of the PS-500V, a single unit can deliver enough power to cover the requirements of almost any high-quality system. The PS-1200V uses waveform shaping technology to turn the power from a regular AC outlet into a highly pure sine waveform for use as a stable anduncontaminated energy source of A/V components. To achieve this, the PS-1200V constantly monitors the input voltage waveform and 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-1200V therefore operates with high efficiency and produces little heat, allowing it to be designed as a fairly compact and lightweight unit. Since it contains no oscillators or switching circuitry, the PS-1200V itself does not act as a source of spurious high-frequency noise. AC Voltage Stabilizer Based on Waveform Shaping Technology The PS-1200V 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- 1200V is very small, since it consists only of the power required for waveform compensation. Figure 1 shows a block diagram of the unit. The signal from the secondary winding S 1 of the trans- former reaches the adding/subtracting circuit and appears at the output as output voltage (e 0). A part of the output voltage is routed to the -“ input of the waveform comparator for waveform comparison. The S 2 signal from the transformer goes to the ref- erence waveform generating circuit where it be- comes the high-precision sine waveform (e i) syn- chronized to the input frequency of 50/60 Hz. This sine wave sig- nal is then routed to the + input of the waveform com- parator to be used as a refer- ence signal. By comparing the two input sig- nals, a differen- tial component is extracted. Based on this information, the adding/sub- tracting circuit can provide ex- actly the re- quired amount of compensa- tion for turning the output into a high-precision sine waveform. Excellent Current Capability The power amplifier which performs waveform compensation is configured as a pure complementary symmetrical circuit using current feedback for unsurpassed operational stability. The output stage uses transistors rated for a maximum current of 15 amperes. These devices are connected in a 20-parallel complementary push- pull arrangement which boasts excellent current capability. Frequency spectrum of power line (photo )Frequency spectrum of PS-1200V output (photo ) Frequency spectrum of power line

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Superior Waveform Compensating Power When 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 3 (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 3 (b). In actual operation, the peak value of 10 V, namely 14.1 V is added or subtracted. Comparing a precise sine wave synchronized to the input frequency with the output voltage yields a compensation waveform which is imposed on the output voltage. Consequently, for an input voltage range of 200-253 V AC (108-132 V AC) and a constant load, the output voltage is kept constant at 230 V ±2% (120 V ±2%), with a maximum distortion ratio of 0.3%. These values demonstrate the outstanding waveform compensation ability of the PS-1200V. Note: The above explanation is for the 230 V AC version of the PS-1200V. Figures in brackets refer to the 120 V AC version. Multiple Protection System Assures Total Operation Safety When a problem occurs during operation, the circuit breaker integrated in the power switch immediately shuts off the power, to protect the unit and any connected components.
When input current overload occurs, such as when the output is short-circuited, the power is shut off. In case of momentary power overload, such as caused by inrush current when a component is switched on or when a power amplifier reproduces a peak passage in the music, a current limiter becomes active. When DC voltage is detected in the output or when the output voltage exceeds the maximum rating, the output is switched off to protect connected components. When the tem- perature of the internal heat sink or power trans- former exceeds 110°C, the cir- cuitry is automati- cally shut down.
Assembly with reference waveform generator etc.Assembly with protection circuitry
Assembly with 20-parallel push- pull output transistors, waveform compensation amplifier for addi- tion/subtraction, comparator for reference waveform and output waveform, etc. (The photograph shows the 230 V AC version.)