Volume control is via the analog outs of the cdp, not the digital out. In any event, I have the Opus 21 and, in my system, I strongly prefer using a separate preamp. However, this is a personal preference thing and largely system dependent, I suppose. You will only know what's best in your system by trying it both ways.
I use the Resolution Audio CD55. It has a variable analog output and I am hooked. I still use a preamp but my preamp doesn't have remote volume so I use the built in volume control on the CD player. I liked it so much I bought a second unit and have one in both systems. Bought both on Audiogon. Their is a fixed output available via a DIN type connector as well. I have compared my player to two of my friends well reviewed Marantz CD players and I feel the Resolution Audio player slightly outperformed both models overall. FYI - the owner/designer of Resolution Audio is a great guy and he makes truly innovative products. I have no ties with them in any way - just saying I like their stuff.
Raysonic 168 is incredible, and affordable. See 6moons review.
I bought one, but had no intention to use the variable out. I found it so good, I sold a $3K preamp!
you will have a hard time equaling the Pass X01 preamp from just a cd player itself. It will be close and may be better in many regards, but in terms of dynamics and control the preamp cannot be matched. I have owned the Opus 21 basic and with GNSC. GNSC brings it closer, but still not 100% there. The newer wadias I have not heard, would be curious how the 581 stacks up direct?
Arbuckle, Have you had the mods done on Opus 21, you must not been happy, from what you wrote you no longer own it? Thanks Tweak 1 I will do a google, there must be other brands that do this? where does the Opus sit in terms of quality of over all preformance in a scale of 1 - 10 compared to payler up to 10,000 range?
Why only a digital volume control, a good analog volume control should be superior. Try Accuphase, Audiomeca, and Audio Aero. Also the Cary CDP's can have volume controls and sound quite good. Happy listening!
I own the Resolution Audio CD-50 and have used it straight into an amp with good results, the balanced outputs are noteworthy. I'll keep this player until it dies and then I'll either purchase another CD-50 or a CD-55. Bradearles comments about the owner of RA are on the money.
Opus 21 is one of the best players made period, in my opinion. I loved the GNSC Opus 21, sold it out of curiosity and now own an Esoteric X03se at almost twice the price. Is it better, yes in some ways. But the Opus is far more flexible, has a digital in and can run amp direct, which annoys me about the Esoteric that they can't have a digital in. I have thought on more than one occasion of saving some cash and going back to the Opus GNSC mod......but again, my point being is a preamp does offer better dynamics, albeit a small increase.
I've had the Pass Labs D-1 dac and ran it direct into my power amps with incredible results. I then ran it through a modded BAT 51 SE pr-amp (a great pre-amp) and was shocked how much better it sounded direct. Since then, I've had the DCS Delius, Audio Aero Capitol 2 and the latest is the Wadia 581SE running direct to monoblocks. I'll never even consider a pre-amp again (unless I win the lotto and go to vinyl). Fully balanced operation (Pass Labs, DCS and Wadia)makes a big difference if you have any distance to travel. I also believe the digital volume when set up correctly is the best sounding. My experience is that pre-amps can add color if that is your goal. But for pacing, separation and ability to handle complicated signals a properly set up dac or cd player running direct is the best cost cutting tool for great sound. Nelson Pass told me that 3 volts from the D-1 would drive my Aleph 1.2's to full output with any length of cable(XLR) and he sells lots of pre-amps. I run my Wadia at 1 volt and can upset my neighbors. Best of luck
Nelson Pass does a nice job of explaining things in an article. You have to go through the wohole thing.
I also use the Opus 21 and still prefer it through a pre.
To clarify my prior response, I have the GNSC modded Opus 21 as well and its a wonderful CDP. When I first got it, I used it as a pre and it did an admirable job; however, inserting a pre into my system really allowed the Opus to do its job as a CDP. The sound stage opened up, etc. Again, this is all system dependent. You have to consider input/output impedences, gain requirements, etc., just as you would in selecting any pre. In MY system a separate pre works better. In yours, using a CDP as your pre may work wonderfully. You will just have to experiment.
Krell made the KPS 25sc which was a pre amp and a CD player and its a fantastic unit. It has a Anolouge vol control and complete pre amp functions!