18 March 2024

ReVox BX350 (1978) - Linear Phase Loudspeaker

 

Linear Phase Loudspeaker

Brand: ReVox
Model: BX350
Year: 1978

Linear phase system. The unique shape of the new ReVox loudspeaker plays an important functional role. The staggered loudspeaker arrangement compensates for the different response times of the various drivers and restores the original phase position within listening distance. This will give excellent impulse reproduction and therefore clean transient response and increased transparency in the width and depth of the sound image. To improve bass reproduction, ReVox came up with something unconventional: four small bass drivers instead of one large one. For bass and mid-range there are four long-throw woofers, each of which has a diameter of just 122 mm. The advantage of this solution: lower distortions, because the individual membranes only have to make comparatively small deflections. Because of the low moving mass of the individual chassis, even medium frequencies can be radiated cleanly. With this concept, ReVox was able to do without a separate midrange driver and design the BX350 as a two-way speaker. The four low-midrange drivers cover the entire frequency range up to 3200 Hertz. This is where the dome tweeter comes in. Revox engineers therefore installed the four woofers on a slightly concave baffle: Each of the four systems radiates in a different direction, which is intended to significantly improve the omnidirectional radiation behavior in the mid range. In order to avoid phase shifts, the four cone speakers and the tweeter are mounted so that the front edges of all voice coils are in one plane.

Technical Data:
2-Way Closed 
Music power: 100 W
Nominal power: 80 W
Frequency Range: 30Hz-20.000Hz
Impedance: 4ohm
Bass-mid: 4x122 mm Rubber surround, die-cast chassis
Tweeter: 25 mm dome
Dimensions: 350x520x295mm (WxHxD)
Weight: 14kg


Linear Phase Loudspeaker

Linear Phase Loudspeaker

Linear Phase Loudspeaker

15 March 2024

PHILIPS System 900 (1978) - Hi-Fi Stereo System

 

Hi-Fi Stereo System

Back in 1978 if you wanted a Top Hi-Fi setup, the "System 900" from Philips might have been just what you were looking for. This 482mm wide Hi-Fi system featured the following components: AH 798 AM-FM Quartz PLL Synthesizer Stereo Receiver with remote control and 40W/ch power rating (see here the one in the 1001hifi collection), N 5846 Metal tape capable cassette deck with a unique "Micro Computer" track programming system and a fabulous mechanism, just like the one used by it's sibling, the 3-head N 2552 seen here. All these were installed in the AH 009 rack that also hold on top of-it the AF 829/II front control turntable. Matching loudspeakers were the AH 489. 

Hi-Fi Stereo System

Hi-Fi Stereo System









14 March 2024

AKAI PS-200 (1979) - Stereo Pre-Power Amplifier

Stereo Pre-Power Amplifier

Brand: AKAI
Model: PS-200C | PS-200M
Year: 1979

The PS-200C preamplifier is characterized by the following properties: The entire signal path is designed using DC differential amplifier technology. The same applies to the phono amplifier, which makes it possible to connect a moving coil pickup system (3-phono inputs). For optimal adaptation to all commercially available pickups, the input impedance of the phono amplifier can be switched between 33, 47 and 100 kOhm. Together with the existing ground terminals, this results in an excellent performance with hum-free phono reproduction. The 250 W/channel professional PS-200M power amplifier, like the PS-200C preamplifier, is designed using DC differential technology. Twin power transformers supply power for this dual mono construction model. Two large power (watt/dB) indicators together with a 9-step peak-power LED display provides information about the power output. There are also electrical protection circuits for overloads, speaker defects or cable short circuits to protect the expensive output transistors. A subsonic filter prevents low-frequency interference caused by record treble or rumble.

AKAI PS-200M
Continuous power: 2X230W (8ohm, DIN)
Total Harmonic Distortion: <0.008%
Frequency Response: DC-100kHz 
Signal to noise: 115dB
Dimensions (WxHxD): 440x200x430 mm
Weight: 29 kg
PS-200C
Dimensions (WxHxD): 440x90x457 mm
Weight: 7.5 kg


Stereo Pre-Power Amplifier

Stereo Pre-Power Amplifier

Stereo Pre-Power Amplifier