As stated in my thread-starting post, yes, the idea here is to make the sonic path as similar as possible. It will be possible to compare the files to the CDs either through my Benchmark DAC3 HGC or through the DAC in my Oppo UDP-205. In all cases, the reading of the bits is done by the Oppo, either through its Blu-ray drive or through its USB 3 ports on the back of the unit. For playback via the Benchmark DAC, the Oppo's HDMI output feeds the Benchmark's coax digital input via my Kanex HDMI de-embedder. From the Benchmark DAC3, the signal goes via balanced analog into the Benchmark HPA4 line/headphone amp. For playback using the Oppo's internal DAC, I feed the Oppo's balanced analog outputs directly into another set of balanced analog inputs of my Benchmark HPA4.
All my discs are now ripped. As predicted, I was able to get everything onto two of the 512 GB Patriot Supersonic Rage 2 USB sticks with plenty of room to spare. I have plugged those into the two USB inputs in the back of the Oppo.
The only major learning curve during the ripping project was naming the folders. No single naming scheme seems optimal to me for both classical and pop music. The dBpoweramp default naming scheme is okay for pop, but terrible for classical discs. If I had it to do over again, I would consider different naming schemes on a disc-by-disc basis for easiest look up by top folder name. With more sophisticated playback software, or if I were using a video monitor in the system, perhaps this would not be a problem (I'm probably showing my ignorance here, but this is all new to me), but the Oppo Media Control app on my iPhone X only shows the top folder name as you scroll through until you pick a program. I will probably just go through and rename some of the top folders which were inadvertently given enigmatic names by dBpoweramp (such as the name of a conductor or soloist) before I began to catch on and modify the default names on a disc-by-disc basis.
In theory (at least the theory accepted by most audio engineers), as long as the bits in the files match the bits on the discs, if the same DAC is used to control the playback timing of those bits, the file playback should sound identical from the files or the discs, at least if the playback signal path prior to the DAC is similar and I've tried to make it as similar as I know how. The AccurateRip function of the dBpoweramp program provides a measure of confidence that the ripped files are bit-for-bit copies of the bits on the discs. Playback jitter should be the same since the timing will be controlled by the same DAC in my comparisons. Some may think that the computer files have an advantage over "live" playback from the optical disc in that the files are certain to be bit accurate, but any given read from the optical disc may not be. However, for most optical discs, the ripping to files done at high speed (4X to 24X normal playback speed) on the El Cheapo Dell DVD drive matched according to AccurateRip on the first pass. I imagine the Blu-ray reader of my Oppo is much more capable of reading CDs and other discs than the Dell, so it really shouldn't be an issue for the Oppo to read the disc in a bit-perfect manner each time.
One thing I didn't realize when I set out to compare the sound of files with disc playback using my Oppo: It seems impossible to switch quickly from the USB stick playback to the disc playback. Once USB playback is engaged, that mode is "sticky" in that there is no way to switch the output of the player to a synced disc playback. In fact, I don't think I can even get the player to play a disc while it is playing from the USB stick. I have to stop the USB playback and close the Oppo Media Control app first before the disc drive will operate. That process, plus cuing up the disc to the part I just listened to from the USB stick takes up to a minute or so.
Initial sonic impressions: So far, sonic differences are truly minimal. No night and day differences and sometimes I've even been fooled as to which source was playing since the Oppo remote control controls both the disc and USB playback once the USB playback is started up. Occasionally disc playback seems to have greater detail, clarity, and greater high frequency smoothness, as well as better replication of hall sound and recording noises in the venue or from the analog tape hiss. I have yet to feel that the file sounded better than the corresponding disc playback. But, again, it's very early in my experiments and the differences I occasionally think I hear seem quite tiny to me.
Stay tuned . . . .
