Teac CD-P 4500

Data

General

  • Manufacturer: Teac
  • Model: CD-P 4500
  • Type: CD-Player
  • Years of manufacture: 1993 - 1994
  • Made in: Japan
  • Color: Black
  • Remote control: yes rc 456
  • Energy consumption: 14 W
  • Dimensions (WxHxD): 435 x 119 x 284 mm
  • Weight: 5.8 kg
  • Original price approx.: 698 DM, 1993


Technical data

  • Drive: KSS-210A
  • Frequency response: 20 Hz - 20 kHz + -1.0 dB
  • Harmonic distortion factor: 0.002% or less
  • Dynamic range: 98 dB or more
  • Noise-to-noise ratio: 105 dB
  • Channel separation: 104 dB or more

Comments









Pictures

  • Picture: Teac CD-P 4500

Teac CD-P 4500-1993.jpg


Reports

  • The D / A converter of the CD-P4500 is a 1-bit DAC "SAA7350GP" (commonly known as the new bitstream DAC) from Philips.
  • SAA7350 is famous for "DAC7" in combination with TDA1547, but it is also an excellent DAC on its own and is also used in Pioneer PD-T07 etc.
  • SAA7350GP is a PDM (Pulse Density Modulation) 1-bit DAC. There are 4 DACs inside and 2 DACs are used for one channel for differential output. The digital data input supports up to 20 bits.
  • With 1-bit DAC, requantization noise occurs when 16-bit data from CD is converted to 1-bit. A circuit called a noise shaper (noise shaping) moves this to a frequency higher than the audible band.
  • The effect of the noise shaper changes depending on the combination of order and oversampling frequency. Simply increasing the order will decrease the noise in the audible band, but increase the so-called high frequency noise, and you will need to increase the order of the low pass filter after the DAC, ie make it stronger.
  • Higher order low-pass filters increase the number of parts, resulting in sound quality degradation and phase shift at high frequencies.
  • Therefore, the SAA7350GP uses a 16.9 MHz clock, the noise shaper is used for 3rd order single stage noise shaping, and the oversampling frequency is increased by 384 times to reduce noise in the audible band.
  • By the way, when it is used as "DAC7" in combination with TDA1547, 1-bit data passed through this noise shaper is sent to TDA1547 for D / A conversion.
  • The digital filter is manufactured by NPC and uses 20bit / 8x oversampling.
  • Servos and signal processing circuits are made of SONY chips. As the pickup and mechanism are also made by Sony, half of the main parts of the CD-P4500 are made by SONY.
  • In function, the pitch control function is executed and the pitch of ± 12% can be adjusted.
  • When you input the length of the cassette, the time editing function automatically programs the songs input on the A and B sides according to the length.
  • Other functions include a random memory program, music jump, cue lock, 4-mode repeat performance, 3-mode time counter, auto memory, index search, music search, timer playback, and indicator ON / OFF function.
  • The chassis is made of sheet steel. The bottom plate is a single 1mm thick steel plate, but the top plate is doubled with a 2mm thick steel plate.
  • There are two beams on both sides of the mechanism to increase the strength of the chassis. Such a structure was adopted in entry-level models in the 1990s, but now only some mid-level and above models are adopted.
  • The interior is the "center mecha" that is popular these days. By optimizing the weight balance and arranging the digital circuit and audio circuit (analog) over the mechanism, it is possible to reduce the interference from the digital circuit to the audio circuit. In particular, for the CD-P4500, the beam also acts as a shielding plate.
  • The layout is an audio circuit on the left. The center is the mechanism and power transformer. The right side is the system control, servo circuit, signal processing and power supply circuit.
  • A noise filter is installed before the power transformer to reduce noise intrusion from household power supplies.
  • The power transformer has a separate winding and is an independent power supply divided into digital circuit, mechanical circuit and audio circuit. The audio capacitor is "SME" from Nippon Chemi-Con.
  • It seems to be a normal level for an entry-level model, but it seems that the noise countermeasures in the power supply for digital circuits are weak, the noise returns to the transformer and from there enters the winding for audio, causing the sound produced the audio circuit worse. It seems to be.
  • When I connected an EMI filter (ferrite) to the power supply line extending from the transformer section to the audio power supply section, the sound became a bit clearer.
  • The power cable is a thin parallel cable.
  • Servos and signal processing circuits are made of SONY chips. The servo control is "CXA1372S" (analog servo), the RF amplifier is "CXA1081S". The signal processing circuitry for EFM demodulation and error correction, and pitch control are "CXD2500AQ."
  • In addition, TI's "SN74LS628N" for the VCO (voltage controlled oscillator) is used for the PLL circuit used during signal processing.
  • The effect of the noise shaper changes depending on the combination of order and oversampling frequency. Simply increasing the order will decrease the noise in the audible band, but increase the so-called high frequency noise, and you will need to increase the order of the low pass filter after the DAC, i.e. make it stronger.
  • The digital filter uses the NPC's 20-bit 8x oversampling "SM5840AP".
  • According to the catalog, the back of the DAC is a DC balanced transmission amplifier, but it is a simple circuit with few parts for a balanced circuit.
  • The recording and drive mechanism are assembly parts from SONY and a model called "KSL-210AFM". It is used in many CD players such as YAMAHA CDX-640 , AIWA EXCELIA XC-003 and NEC CD-720 .
  • There are two output connectors, fixed and variable analog. Digital is a light system.
  • In addition, there is a terminal for synchronizing a CD player and a cassette deck.


Links

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