How important is the transport when using a DAC?

Gumby - yes, di/dt is the change in current over time. It is the dynamics changing load and resultant current. If the load changes and the regulator cannot respond quickly enough, you get distortion, lack of focus.

This is by no means microscopic. It is a function of the power supply AND the power decoupling at the load and all of the wires and traces bewteen the two.

LI batteries, particularly combined with ultracaps can outperform most regulator designs except the very best.

Its the very best discrete regulator designs that I use. They are faster than the best LI battery supply and very low noise. Critically damped, so no overshoot when responding to transient load changes. These are designs by Paul Hynes that have been optimized by me for digital.

Steve N.
Empirical Audio

OK, this is late in the game for this thread and slightly off topic, but the insights provided here may be helpful to me. I have an Arcam AVR400 receiver and have been trying to set up a modest music and HT system around it and Monitor Audio Apex A40 fronts and Apex A10 rear speakers and B&W PV1D sub. I currently have and old Yamaha CD player but was hoping to be able to use my Blu-Ray player as a transport with the Arcam internal DACs at first and eventually upgrading to an external DAC for two channel.

Multichannel DTS and Dolby Blu-Rays on a Panasonic BDP and CDs played on the Yamaha sounded great through the Arcam, but the Panasonic as a transport for Redbook two channel using either HDMI or Toslink optical cables was not good. Clear but lifeless sound, no swing whatsoever. USB Redbook FLAC files on flash drive plugged directly into the Arcam sounded similarly sterile. I was thinking that the problem was with the Arcam DACs for two channel.

Then my Panasonic BDP quit working reliably, so I replaced it with a new Samsung BD-H6500 which was really well reviewed in Sound and Vision. Using the Samsung as a transport for CDs the sound is completely different, much better, and closer to the Arcam fed by my vinyl analog set up. Good pace and timing, tone, spatial resolution, etc. The Samsung has the ability to feed the Arcam AVR raw bit stream data, and this setting makes a big difference using the Toslink optical cable.

Question for this group, WHY DOES RAW BITSTREAM OF CD DATA FROM SAMSUNG SOUND BETTER ON THE ARCAM THAN THE SAME FILES RIPPED ON FLASH DRIVES PLUGGED DIRECTLY INTO THE ARCAM? AND WHY IS THE SAMSUNG MASS-PRODUCED BLU-RAY SO MUCH BETTER SOUNDING THAN THE SIMILARLY PRICED PANASONIC FOR REDBOOK WHEN THEY ARE VERY SIMILAR SOUNDING FOR DTS OR DOLBY MULTICHANNEL AUDIO?

Thanks in advance for any insights.

kn

One thought occurred to me. For the difference between the CD sound and the flash drive, am I just hearing the difference between ripped FLAC files and the digital files on the original CD?

There a lot of variables here. The most obvious is that the jitter when playing 44.1 may be higher. Another is the digital filtering in the DAC, which usually sounds worse at 44.1. Another is the playback software, which has a large influence on the sound of playback of digital files. Another is the ripping software you used for the CD rips to hard disk.

FLAC files do sound a bit worse than native .wav, but you must really have a resolving system to hear this. Its not that obvious. I doubt if this is the problem.

I would recommend to first do the easy stuff, namely the player and ripper. See this for recommendations:

http://www.empiricalaudio.com/computer-audio/

Steve N.
Empirical Audio

Thanks for the reply. There is no user controlable software in this playback really other than what's built into the receiver. It sees files on flash drive plugged directly into the back and if compatible, it plays them. Control of CDs is handled by the Samsung BDP. FWIW, the files on the flash drive played through the Samsung USB port don't sound as good as CD version of same played through the Samsung either.

I have been ripping files for a long time. Old days I used a desktop Mac and external LaCie disk drive built like a tank. Those rips sounded fantastic in AIFF for 16/44 or MP4s. Since migrating to PC Dell laptop am using Foobar, but mostly JRiver Media Center 18 for file management and playback. Media Center is clearly superior to iTunes, Windows Media Player, etc. for playback on my computer based office system, but that is irrelevant to my HT system at home, at least for now. HD tracks recommends FLAC for download format to maintain sound quality, and I have been ripping CDs using same, but I am beginning to question that.

Finally, I am surprised how good the Samsung sounds when set to output raw bitstream data compared to PCM from Redbook CDs. Not sure option to defeat any processing of data before sending to the AVR was available on the Panasonic BDP I was using previously, but it clearly sounds much better on the Samsung. I would like to compare Samsung used as CD transport with digital out from higher quality CD player or single purpose transport. Not saying Samsung is a giant killer, but it sounds surprisingly good, considering 1.5 lbs total weight, plastic construction, fixed power cord and all.

kn