Wouter's page : My Harman / Kardon HD720

It got a rave review by Deon Schoeman "Exceptional composure, detail, staging and musicality. Rivals players many times the price." in the December 1998 issue of Audio Video SA magazine, one of the reasons I bought it.

Failed to impress.

Lesson: It's a mistake to believe a glowing review on page N of a magazine if the same product is advertised on page N+1.

Here's a different take "rather coarse and uninvolving, like a cheap machine that's trying too hard to gain attention".

Turns out the HD720 uses the Burr-Brown PCM1710, which is widely regarded as the worst DAC that Burr-Brown ever made.

And for the record, the AVSA review is technically incorrect as well -- the HD720 uses a single PCM1710, not two. With a cheap "watch crystal" type 16,9344 MHz crystal.

It does however have a digital output -- the other reason I bought it. Fortunately my AMC-R9 A/V amp has both optical and copper digital inputs.

PCM1710 Internals and Application Note

PCM1710 internals

PCM1710 application

OK, having got that out of the way, I must say that the HD720 is well designed. The output amplifier is all transistor, not an op-amp in sight. And the layout is well balanced. <sigh> They tried.

Other chips include the Sanyo LB1641 Bidirectional Motor Driver, LA9240M Analogue Signal Processor and LC78621 CD DSP. The Microcontroller controlling all of this as well as the front panel is a Sanyo LC866012.

It's interesting to note that the LC78621 includes a single bit D/A converter, which is not used in this application.

Move ahead to 2021, and the service manual is free to download. I love living in the future.

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hits since 2003-07-07.

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