Integrated Amplifiers
Harman Kardon HK 990 Stereo Integrated Amplifier with Digital Room Correction and Dual Subwoofer Bass Management – Part II
- Written by Dr. David A. Rich
- Published on 27 October 2011
- Harman Kardon HK 990 Stereo Integrated Amplifier with Digital Room Correction and Dual Subwoofer Bass Management – Part II
- Page 2: HK 990 Looking Inside the Unit
- Page 3: HK 990 Digital Signal Selector, Clock and Data Recovery, Jitter Reduction, and Digital Reconstruction Filtering
- Page 4: Analog Input Signal Flow of the HK 990
- Page 5: HK 990 Digital Signal Processing and DAC Block
- Page 6: HK 990 Digital to Analog Conversion (DAC)
- Page 7: HK 990 Improving Performance by Operating a Pair of DACS in a Balanced Configuration
- Page 8: HK 990 Backend Analog Circuitry
- Page 9: Conclusions
- All Pages
Introduction to the Harman Kardon HK 990 Stereo Integrated Amplifier with Digital Room Correction and Dual Subwoofer Bass Management – Part II
This second part of the HK 990 review examines the signal flows in the HK 990 dual-domain integrated amplifier. This analysis is relevant to all units, including modem AVRs, with a DSP signal processing unit in the main signal path. The signal flow is more transparent in this stereo unit than a 7.1 multichannel unit; so, if you are interested in AVR, please stay tuned in to Part 2.
Analog circuit design methods for consumer high-fidelity products date to 1950 with the emergence of reel tape, LPs, and FM. Consumer-friendly discussions of analog component design are found in early (circa 1947) issues of Audio Magazine and early (circa 1951) issues of High Fidelity. Digital recording and CD players arrived at a time that magazines were still somewhat technical. It was not until Dolby Digital (originally called AC-3) started coming off Laser Discs in the mid-1990's that units with core DSP processors appeared. By that time, the print magazines had de-emphasized technical aspects of design, preferring to focus on measurements results at the terminals of the DUT.
Specifications
- Design: Solid State Stereo Integrated Amplifier
- Power: 2 x 150 watts RMS into 8 ohms @ 20 Hz - 20 kHz, 2 x 300 Watts into 4 Ohms
- MFR: 10 Hz – 100 kHz
- THD: <0.07% at Full Output (8 Ohm Load)
- Analog Inputs: 7, Plus 1 Phono MC, 1 Phono MM, and 1 Balanced XLR
- Digital Inputs: 1 HRS-Link, 2 Optical Digital, 2 Coaxial Digital
- Analog Input Sensitivity/Impedance: 350mV/43k ohms for tuner/CD, 10mV/47k ohms for Phono-MM, 1mV/100k ohms for Phono-MC
- Digital Input Capability: All Standard Digital Formats
- Dimensions: 6.4" H x 17.3" W x 17.5" D
- Weight: 43.2 Pounds
- MSRP: $2,599 USA
- Harman Kardon
- SECRETS Tags: Harman Kardon, HK 990
Part II of this series examines the dual-domain DSP based system at a deeper level than the treatment found in most reviews, but it is not so technical as to leave an interested audiophile puzzled.
