Technical Articles and Editorials

AVR - Audio Video Receiver - Build Quality: Part I

ARTICLE INDEX

Chart Presenting Build DACs used in AVRs Across Manufacturers and Price

Performance of the digital-to-analog (DAC) converter chip is wide-ranging across manufacturers and models. DAC performance with decreasing SNR is listed on the following chart. The ranking includes all DAC manufacturers actively producing parts found in AVRs. The main column for the SNR is for all channels of the DAC producing independent signal (two or eight channels).

The rankings are done with the worst-case values of SNR shown in red. For the ESS parts, this article in SECRETS is the first public disclosure of the worst case SNR figures. Only typical numbers are found on the ESS datasheets on the website.

The SNR values in the chart are the A-weighted values.

A separate column of SNR values supplied when the DAC is operated in mono mode if the DACs data sheet provided a value for this. For the special case of an ESS Octal parts operated in stereo mode (four current outputs connected together), the SNR value is shown at the rightmost position on the chart.

The THD of the DACs is also shown. ESS and Wolfson do not supply worst case distortion numbers. I have not provided information about the performance of the digital filter incorporated in the DAC chip to prevent the charts from becoming too cluttered with data.

Performance of some DACs changes with the sampling rate. Datasheets often provide specifications for sampling rates of 96K samples/sec and 192K samples/sec in addition to 48k samples/sec. Again, to make the chart readable I have only shown the data for 48k samples / second.

At the right of the chart are products with the DAC. As can be seen, several different companies may deploy the same DAC. The price of the AVR need not correlate with DAC performance. One product, for example, the $500 Harman Kardon AV1700 has DACs that have 108dB worst-case SNR spec and -94dB worst case THD spec. On the other hand, a $1600 Marantz AV1700 has a DAC with a 102dB worst case and -86dB worst case, respectively.

Towards the negative, I identified a couple companies who relatively recently downgraded a DAC for a given price point.

Towards the positive, improved DAC performance is evident in the just announced top of the line products from Pioneer and Yamaha. I have listed these units alongside older offerings to illustrate the improvements.

Most changes in DACs, for a given company, at a given price point, are lateral with a change less than +/- 3dB change in SNR or THD. Another semiconductor vendor may have won the socket or a part may have been discontinued and replaced by the incumbent vendor.

Some of the best DACs from the top manufacturers are not currently being used. Under these circumstances, I listed an older AVR that used the part. In some cases, I could only find two-channel products currently using these parts. I still listed the DACs since I wanted to show differences among the best parts from all DAC producers.

A small subset of AVRs may use lower performing DACs for extra surround or subwoofer channels. I do not note this in the chart. The chart (Table 1) is seen on the next page.