It depends upon the quality of the DAC in your receiver. It may or may not be better than the analog output of your CD players.
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When you connect via a digital cable, the digital to analog conversion is performed in the receiver. When connected via analog interconnects, the digital to analog conversion is performed in the CD player. Really it is going to come down to a matter of preference.
If you really want to "hear the difference" connect either CD player using both the analog and digital cable and then just switch the chosen input on the receiver to determine if you prefer the analog or digital option.
There are two primary parts inside each of your CD players, a transport that picks up the digital signal and then a digital-to-analog converter.
When you use the digital output on either the NAD or the Rotel you're picking up the signal after it leaves the transport but before it gets to the digital-to-analog converter in those players and sending it instead to a digital-to-analog converter in your A-V receiver.
So, with your three pieces of gear you've got two choices of transports and three choices of digital-to-analog converters. If the two transports are of equal quality and none of the three digital-to-analog converters are noticeably better than the other two you're not going to hear a big difference.
The advantage of using the digital output is primarily if you're going to send the digital signal to a separate D/A converter that is audibly superior to the one that's inside the CD player.
Thanks very much. Appreciate the education on this. It's always so much better to hear this from fellow hobbyists who speak in layman's terms. I'll continue to experiment and compare the sound. One thing I noticed was that on some CD-R's, the NAD becomes a bit jittery. With the digital cable, the jitteriness seems to have lessened. Perhaps this has something to do with a faster signal since the conversion is taking place in the receiver. I read in the NAD owners manual that the digital ouptut could help minimize or eliminate jitteriness. Thanks again.
Actually, there is another issue that has not been discussed yet. Most A/V receivers are basically digital devices so analog signals are first converted to digital (via a ADC) for processing through the receiver and then converted to analogue (via a DAC) for output to the speakers.
Option 1: Use Digital Output from CD Player
The outputs the digital signal to the A/V Receiver which processes the signal and then uses it's DAC to convert to analogue. A total of one conversion between Analog and Digital
Option 2: Use Analogue Output from CD Player
The CD player uses it's DAC to convert to analogue. The A/V receiver then uses its ADC to convert the input back to digital, processes the digital signal (volume, dolby or any other effects), runs it through it's DAC and outputs an analogue signal to the speakers. A total of three conversions between Analog and Digital.
Consequently, with an A/V receiver, it usually doesn't matter what quality of DAC you have in your CD player since there you are almost always stuck using the DAC in the A/V receiver. You might as well minimize the conversions and just feed the digital signal directly to the A/V receiver.
The exception to this is where the A/V receiver has a pure direct (or equivalent) mode; this mode will usually handle 2 channel analog signals as analog signals and you should not have the extra conversions so you may be better off with the CD players DAC.
For further information on this subject refer to the following link:
Good post and it hits home to me. I have had cd separates for years, the Cal Audio Alpha and Delta. The dealer who sold me the units recommended a certain cable and I stuck with it for a few years. He then sold me a balanced interconnect when I chose to upgrade. I'm ashamed to ay that by accident I found out that I had been sold analog interconnects for that critical connection between transport and dac. I ordered a digital cable from Signal cable and did notice a difference right away. I fumed for a few days when I thought about not having the optimum connections for years.
I know exactly how you feel. Hey I've had things connected wrong, speakers not balanced via dB's, inferior cables, speakers not located optimally in the room, wrong settings on my A-V receiver, etc for many months. You think you're doing it right until you either read it or someone straightens you out. That's all part of the learning curve in this hobby. In your case, it was your own Hi-Fi sales person that seems to have misled you. I see how that can really disappoint you. I've learned a lot just following this forum. This is a fantastic way to come to speed as they say. Keep asking and posting.
All good points. However, my advice would be to sell the Rotel and the NAD and buy one device that is of higher quality and sounds better than either. This could be another stand alone player if you wish, or some sort of device to stream audio files from your computer (many choices here). Option #2 is likely to give you better sound quality.
I agree that it does come down to personal preference. It takes work to test these things.
Same levels (measured) ,same interconnects, same associated equipment, same ambient noise,same exact location, same feet, same warmup period,same mindset..
Then when you feel confident you have not changed anything else you can make a fair comparison. I am currently listening to a lexicon rt-10 through rca analog and hopefully my rotel rsp-960 preamp is not converting it because I would rather believe the $2500 player is responsible for the beauty.