PIONEER CS-3000A (1973) | World of Wider Bandwidth

 

The original CS-3000 was introduced by Pioneer in 1971. It was highly praised for its excellent mid and high-range reproduction, but bass reproduction was said to be a weak point of the CS-3000. To solve this problem Pioneer introduced the CS-3000A with an improved woofer. The newly developed woofer had the same 30cm diameter, but the magnet was equipped with a large 200mm diameter ferrite magnet. The center pole was covered with a pure copper cap, just like the CS-3000, to suppress distortion caused by the nonlinearity of magnetic materials. The frame had a sturdy structure made of die-cast aluminum, eliminating resonance. This cone paper was newly developed for the CS-3000A, and the center cap was made of the same material as the cone paper, with wavy bumps to increase its strength. The cone edge was made of foamed urethane, just like the CS-3000. The cone neck inside the center cap had a new mechanism that used a special open-cell foam. It suppressed nonlinear distortion caused by air circulation inside the cap, and also acted as a mechanical filter to prevent abnormal sounds caused by concentrated compliance in the neck. The damper had a symmetrically arranged double damper structure, which improved the linearity and reliability of the suspension. The voice coil was edgewise wound with aluminum ribbon wire, just like the CS-3000, and the aluminum foil ribbon, heat-curing epoxy resin, and short winding effect improved the heat dissipation effect and improved input resistance. As described above, the CS-3000A is a model that strengthens the bass section of the CS-3000, and is a powerful unit that realizes stronger bass reproduction capabilities to match the excellent mid- and high-range sounds. The midrange was equipped with a 6.5 cm diameter dome-shaped unit. The 6.5 cm diameter dome-shaped diaphragm made of duralumin kept the amplitude small, reduced IM distortion, and ensured low-frequency reproduction capability up to 700 Hz. The tweeter was a 2.0cm diameter dome type. It was a combination of a duralumin dome with a diameter of 20mm and a thickness of 30μ, a double-layered urethane foam edge, and an edgewise wound voice coil with aluminum ribbon wire. The network was equipped with a 700 Hz and 6000 Hz crossover with an attenuation of 12 dB/oct. The feature of this network is that the impedance rise at the f.o of the midrange and tweeter was corrected by a compensation circuit, and the impedance of each speaker was made flat, which resulted in a straightforward cutoff characteristic and improved phase characteristics. The level control was performed by simultaneous switching of the coil step-down and compensation resistor, and the midrange could be switched in four steps of 2 dB, and the high range could be switched in five steps of 2 dB. The enclosure was a completely sealed type (air suspension type) and used a combination of 25 mm thick hard particle board and lauan plywood. Instead of the conventional rod-shaped reinforcement, the internal reinforcement was a flat plate with four small holes, which reinforced the front, back, left and right sides while preventing standing waves. In addition, 800g of glass wool was built in, providing effective internal treatment. The enclosure baffle surface was flat, and the grill net was also designed to prevent deterioration of the playback characteristics. The surface was finished with Brazilian rosewood, giving it a high-class feel. The CS-3000A could be single, bi or tri amplified.

Specifications:

3-way Infinite Baffle

30cm Bass

6,5 Dome midrange

2,5 Dome tweeter

Frequency range: 30-20.000Hz

Power rating 100W

Impedance 8ohm

Size (WxHxD): 360x630x327mm

Weight: 33kg 

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Technics High Grade Components (1976)

 

Pictured High Grade Compnents from Technics are:

(Top to bottom, left to right)

SB-7000 "Linear Phase" 3-Way Speaker System

SE-9600 Stereo Power Amplifier

SH-9090 Universal Frequency Equalizer (mono)

SP-10MKII/205C-11H/EPA-100/SH-10B Turntable/Cartridge/Tonearm/Turntable base

TE-903 Audio Timer

RS-690U Tape Transport

SU-9600 Stereo Control Center

RS-1500U 2-Track Reel to Reel Recorder

SH-830 Audio Rack

RS-690U Stereo Record/Reproduce Amplifier

SH-9090 Universal Frequency Equalizer (mono)

ST-9700 FM Stereo Tuner

SL-1350/205C-11S Direct Drive Automatic Player System/Cartridge

SB-7000 "Linear Phase" 3-Way Speaker System

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SANSUI AU-alpha907NRA (1998)

 

A flagship model that will create history in sound. The pinnacle of integrated amplifiers, the "907" models have changed throughout the years. Now here is the AU-alpha907NRA. Equipped with the Ultimate Q-X balanced circuit, which brings together the best of Sansui's original technology. The current margin of the driver stage has been doubled to Class A operation, and the circuit itself has achieved outstanding dynamic characteristics and wide range and high speed in all transmission and amplification processes. The final stage has been changed to a single drive balanced push-pull configuration, and is equipped with a NM-LAPT with Pc (collector loss) of 200W, which is suitable for high power amplification, which was used in the power amplifier B-2302. The powerful power supply section uses a high-performance power transformer with a total weight of 13kg. By sealing a high-density filler inside the four-layer shield, vibration during operation has been suppressed and the stable current supply capacity has been greatly improved. The capacitors, film capacitors, and resistors are of the highest standard, developed for Sansui's VINTAGE series, and are used in an ideal combination. The speakers are connected to terminals made of OFC alloy and 24-carat hardened gold plated by WBT of Germany, which has little signal loss. Banana plugs are also supported. The pure copper elliptical insulators made of genuine leather, which provide excellent vibration damping properties, and the volume knob machined from solid aluminum are all carefully considered to maintain the purity of the sound. The music signal is transmitted and amplified with high purity by connecting it from input to output in the shortest possible distance. The signal connected to the three direct inputs is sent directly to the power amplifier section without passing through the preamplifier circuit. In addition, a balanced input terminal is also provided, allowing you to create an ideal balanced operating environment for the entire system. A new heat sink with an elliptical hole on which the power board equipped with the isolated mechanical feedback steel plate and the Ultimate X-Balance circuit is assembled. In the 907NRA, the power transformer, the largest source of vibration, is mounted floating from the chassis. This isolates the power supply system from vibrations and eliminates mechanical interference. In addition, the heat sink, which acts as a resonating plate when mounted directly on the power transistor, has been thoroughly redesigned to effectively disperse the resonating effect. Combined with the reinforced twin mono construction that structurally controls the vibrations of the power supply and signal systems and the isolated mechanical feedback that effectively blocks the transmission route of vibration, this complete vibration countermeasure realizes ideal sound field performance. Good Design Award winning product.

Main specifications 

Power amplifier section 160W+160W (8oHm) 

Total harmonic distortion (at effective output): 0.003% 

Damping factor: 150 

Frequency response (1W): DC~300kHz

External dimensions: 462 (W) x 165 (H) x 448(D)mm 

Weight: 33.0kg

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