Burr Brown DAC with HDCD Decoding

[vortecjr]

I found this cool HDCD DAC while looking for a unit to test things on.



DESCRIPTION
EVM-1702 is an evaluation module based on Burr-Brown’s superior 20-bit DAC, the PCM1702. The system has excellent sound quality and high performance achieved by combining ISO150 digital isolators with high speed op amps OPA627 and OPA2604.

A parallel connection technique has been used where the same left channel (right channel) digital data is sent to four independent PCM1702’s whose analog outputs are then combined to produce the left channel (right channel) analog output for the system. As a result, EVM-1702 has superior audio performance, very low THD+N, wide dynamic range and high S/N ratio.

The EVM-1702 is used in conjunction with a HDCD decoder, provided by the Pacific Microsonic Corporation, to play HDCD encoded discs. EVM-1702 has an optional 2nd PLL circuit (not installed)
that can be used for applications with low jitter requirements.

FEATURES
* PRECISION DAC BOARD WITH 20-BIT RESOLUTION
* STANDARD DIGITAL AUDIO INTERFACE (S/PDIF, EIAJ-1201) OPTICAL OR COAX INPUT
* SAMPLING RATE: 32kHz to 48kHz
* COMPLETE ISOLATION FOR DIGITAL/ANALOG
* HDCD DECODE FUNCTION
* 8X OVERSAMPLING DIGITAL FILTER
* 4 PCM1702 DACs PER CHANNEL (connected in parallel)
* HIGH PERFORMANCE
THD+N: –90dB (16-bit)
–100dB (20-bit)
Dynamic Range: 98dB (16-bit, EIAJ)
112dB (20-bit, EIAJ)
S/N Ratio: 118dB (EIAJ)
* 2ND-ORDER POST LPF
* POWER SUPPLY
Digital: +5V
Analog: ±5V, ±8V, ±15V
* BOARD SIZE: 297mm X 210mm (A4)

[simon.pepper]

And how does it sound?

The Naim NDS and ND555 reference players use the PCM1704K chips, similar ladder R2R DACs to the PCM1702 but offering 24-bit support.
Will offer a different sound to a Delta/Sigmar chips. The BB PCM17xx family is still thought as, the best sounding DAC chips produced!

[vortecjr]

With HDCD jazz and blues content its sounding very nice.

I'll see what other sample rates its supports because the HDCD PDM100 IC supports up to 24bit at 50kHz. The HDCD PDM100 IC then has several programed dither options if it's going to reduce the bits. The HDCD PDM100 IC also up samples none HDCD content via several programed sample rate options. The combination seems well implemented.

[simon.pepper]

The Pacific Microsonic devices were also top notch - had a Pink Triangle DAC, many years ago, with the option of different filter units, one using Pacific Microsonic devices. That sounded great.

[vortecjr]

The DAC played fine with 24/48 content.