HISTORY: Compact Disc technology is 40+ years old. Co-designed by Philips and Sony in the early 1980s the standard for the CD's PCM audio became known as "Redbook"with a 44.1kHz sampling rate and 16-bits of resolution. The earliest CD players in the 1980s used simple 2X oversampling which evolved quickly into 4X, 8X versions (and higher) in the 1990s. Yet despite the yearly release of players with new and revolutionary sampling techniques they were always constrained by the CD's 44kHz 16-bit format.

Notably in 1999 while CD technology was in full swing a new format was created by Philips and Sony called SACD. Instead of PCM it used a process called DSD with a sampling frequency of 2.8224 MHz (64 times the sampling rate of 44.1 kHz). This delivered a dynamic range of 120 dB from 20 Hz to 20 kHz and an extended frequency response up to 100 kHz(!) Early discs came with only a SACD layer meaning a CD player capable of playing SACD was required. Later discs were "hybrid" discs with both a PCM layer and SACD track making them more universal. Yet despite their superiority they didn't capture the interest of the general public. It didn't help that CDs were losing market share at this time due to the popularity of MP3 and Ipods. The result was the decades-old concept of building an audiophile listening-salon to demo the purest version of a music track changed. Almost overnight the audio world raced to begin supporting compressed MP3s designed for trendy, portable players. So its no surprise that with the CD world slowly fading that by 2007 SACD was considered a commercial failure.

Denon was a division of Nippon Columbia and was originally involved in the broadcast industry producing a quality line of commercial equipment in addition to their consumer line. They were instrumental in popularizing and mainstreaming the use of high-quality Burr-Brown DA converters in consumer digital equipment. However, Denon began altering their CD players in the early 2000s by adding DVD video circuits to make the players more universal. This allowed the CD format limp along for a few more years until 2007 when Blu-Ray discs hit the scene upon which standalone CD players all but evaporated from the mainstream consumer market. As of 2024 a few CD players are back on the market despite CDs being obsolete.

BELOW: this is my Denon DVD-2900 which debuted in 2003 at $999 retail. At a heavy 21.5 pounds it plays CD/SACD and standard DVDs. With a 192kHz/24-bit Burr-Brown audio D/A converter and several features to maximize audio quality it was one of Denons last audiophile-aimed CD players before video became the standard selling point. The power supply board is on the left with the laser-sled assembly in the center. The green board on the top right is the video board while the black board beneath it is the audio. That Denon intentionally isolated the audio and video boards shows attention to detail.

BELOW: The audio board is very straightforward as 100% of the electrolytics are audio-grade Elna Silmics or Silmic IIs. The blue caps are listed as "film" types in the Denon service manual and are likely mylar. The two audio opamps are "OP275" models. OP725s are rated as Low Noise, with distortion of 0.0006%, a high slew rate of 22 V/us, and a wide Bandwidth of 9 MHz. I see no reason to change them out. I decided to leave the caps alone as well.

THE SURPRISING MOD: I didn't plan on making any changes to this unit. But after I poked around inside for the photos above I demoed it and was surprised by a sudden increase in sound quality (?!) Air and presence were more vivid and palpable and voices sounded more "live". Was I imagining this being in a good mood or had I changed something? I realized I had forgotten to reconnect the thin ribbon cable to the video board (see red arrow above). Weird. Did not connecting the video board cable somehow improve the sound? The "Pure Direct" knob on the front shuts off all video outputs to improve audio quality but could unplugging the entire video board have also made a difference? Was there some vague interaction from the video circuit that makes an audible difference to the SACD circuit which has response up to 100mHz? I didn't know what to think.

So I spent about 20 minutes with the top off the player demoing my favorite tracks with the ribbon on and of, back and forth. After about 10 swaps I determined that yes, with the video cable off the sound quality really was better. The instruments had more "pop" and voices had a dynamic "live" quality. With the cable on the music had a slightly smoother presentation. I tried convincing myself I was imagining things but it was consistently audible on both CD and SACD. The player seemed to not care that the video was unplugged and audio functions were perfectly fine.

I decided to leave the video board in place but unplug its ribbon and power plug completely. Its 20 years old so there's no guilt. I can always plug the board back in if I want to return it to stock.