Harman/kardon HD 7725 specifications

Category : CD-Player

General

Connections

Tech nical data

Special features

Outputs:
- 2 x RCA (1 x fixed, 1 x variable)
- 1 x Digital Coaxial
- 1 x Digital Toslink (SPDIF)

Frequency Response: 2 Hz - 20 kHz
Distortion: 0.0025%
Dynamic Range: 98 dB
Noise Ratio: 104 dB
Channel separation: 98 dB
Output voltage: 2.1V
Output resistance: 150 ohm (fixed); 1250 ohm (variable).
Error correction: CIRC system, moderate error correction according to the test in Stereoplay 4/93.
Reinforced chassis, remote control.

The Flagship of Harman/Kardon from 1993. Elaborately constructed CD player.
It has an anti-distortion concept RLS (Real Time Linear Smoothing), which divides the data stream into two 18-bit converters (PCM 61 K) per channel, one receives it with a time offset by one sample value. The Burr-Brown converter is an R2R converter whose current output applied to the IC pin is fed back directly to the PIN of the internal operational amplifier in the Burr-Brown standard circuit used in the HD7725. The voltage-converted differential signal of both converters by the DAC-internal OPs reflects the course of the output curve. With this, Harman fed a capacitor that cannot change its voltage by leaps and bounds, but only continuously, and thus smoothes the step-shaped converter output signal, that is, the signal already corresponds almost exactly to the music signal. * After the converters there is a complex summing double differential amplifier stage, which is constructed discretely with single transistors. Both outputs, for the fixed and the variable, are constructed discretely with single transistors. Output coupling capacitors have 220uF/25V (Panasonic "Pureism").

General data:
Dual 18-bit linear Burr Brown DA/converter (PCM61K) per channel in highest (K) selection, Real Time Linear Smoothing (RLS) technique (probably the first generation), tapping of the voltage output on the converter IC.
Discretely constructed output stage for the fixed and variable chinch output.
Differential amplifier discretely constructed!
Discrete, separate for the digital and analog range, built-up power supply!
Adjustable headphone amplifier, this has a dual OPV NJM4565 installed.

Harman/kardon HD 7725