help with DAC w/current system

I've never used an outboard DAC before, but have a chance at a killer deal on a Classe DAC-1 (Stereophile class A, $4000 retail). I currently have a Rega Planet CD player with a nice Classe amp and B&W speakers. Does anyone know what and how much of an effect a DAC like this would have on a system of this caliber? Any ideas would be appreciated.
The Rega is a good product, but the Classe D/A will improve its overall sound in every sonic parameter. That said, the differences will not be dramatic. The upgrade will be readily apparent, but don't expect, at least in the long-term, a night in day difference. Relatively speaking the Classe D/A is an older design. I would recommend you not pay more than $1,250. Also, the digital cable is critical. It pays big-time to experiment and there is little correlation between price and performance with this type of product.
What about a newer DAC, such as the MSB link III w/upsampling and all the goodies? Would the upsampling, HDCD, and future upgradeability be a better value in the long run?
I guess Audioguy that would be a decision you would have to make. With the format wars on going one should tread lightly until something is finalized. My dac has hdcd but I don't see that many discs with hdcd on the label. With the msb at least there is the upgradeability you mentioned.
With all respects for Audioguy3107 and his suggestion of the MSB Link Dac 111. The Link Dac 111 will not hold a candle to the sound quality of the (20 Bit non upgradable) Classe Dac 1. If you can get a good deal on the Classe Dac 1 by all means go for it. The Classe is a very musical sounding Dac and will integrate well with your system. As stated by Onhwy the digital cable you choose will play a big part for the sound quality with the Classe Dac 1.
I agree with Mikec, I also believe that when you play music that you know well, you will be surprised at some details you will hear that you never heard before (IMHO). Good Luck, let us know what you decide to do, and how it sounds if you make the purchase.
Based on my experience, most ot the newer 24 bit dacs are much better, then any of the older 20 bits converters. This holds true even for the modestly priced 24 bit dacs, like a modified MSB Link. (Assuming that it has a modified output section ,like a Stan Warren mod, which is only a couple hundred dollars). I hold Classe products in very high regard, but if this particular Classe does not have 24bit converters, you can probably do better. The newer 24 bit dacs are that good! Ever wondered why so many 20 bit Theta's and Levinson's are now dirt cheap on the used market?
Ehider, you make a very good point. Audioguy3107 needs a home demo to detenmine whats best.
I believe a good outboard DAC will make a huge difference in your system. The original Planet was an excellent product but widely held to be tuned down to sound more analog-like--it's also said to make a good transport. A good DAC will strip away all the veils and open up the sound significantly while preserving the musicality.

I can't speak to the Classe DAC, but if it's been out for a while it's probably using technology that's a few generations old and not upgradeable. It probably was excellent for its time, but technology has moved so fast, especially with DACs, that I think you're better off going with something more current.

That said, I would highly recommend trying the Electronic Visionary System's new Millennium DAC II that you can get for around $1050. You can try it risk free for 30 days, and I'd be willing to bet you won't send it back. I've had the original Millennum DAC 1 for a year, and it handily beat my Dusty Vawder modified MSB Link DAC that it replaced. The DAC II uses even higher quality parts, better(i.e. more minimalist) design, and does upsampling and is upgradeable to SACD/DVD-A. You've got nothing to lose and everything to gain.

As for cables, I agree with others that this makes a big difference. If you don't want to break the bank you can get an Apogee Wyde Eye cable that runs about $30 for 0.5m and will get you a good part of the way there(hard to find, but I found mine at Guitar Center as Apogee cables are used frequently in professional setups). I've also heard good things about the DH Labs digital cable, but after that I think you're well into the triple digits to get significant improvement(Illuminations, Acoustic Zen, etc.). Start with the Wyde Eye--it'll tell you what you need to know and you can experiment from there.

I'm upgrading to the DAC II and then waiting a year or two until the new formats mature a bit and the dust settles--I won't buy this stuff until there's a digital out, and that may take a while. I also might add the Perpetual Technologies P1A to my DAC to get true 24 bit interpolation(different from upsampling) and room correction capabilities(HUGE benefits to any system). Best of luck.

The Mapleshade Double Helix digital cable is $120.00 new. I use it with the Bel Canto DAC and love the sound which is organic/analog like with fine detail and full bass. They have a less expensive version for $32.50 new (I have not tried this one). Both are with a 30 day return.
I have Classe CDT-1 and DAC-1. Cables are important and I recommend the Illuminations Orchid. You also might want to try a Monarchy DIP between the transport and DAC. I've been experimenting with the DIP, Illuminations Orchid and D-60. All of them provided improved performance to varying degrees.
I would recommend the Classe over the MSB. In my auditioning, IMO, I think the older units with top level analog sections, will beat the newer digital chips with cheaper analog sections. The MSB Platinum will beat the Classe, but you're talking $3k. At the price poin a used Classe goes for (around $1100) I don't think you can go wrong. I've heard the Perp. Tech stuff and the Bel Canto too. It's good stuff at its price point, but I feel the analog section is more important than the digital chips, therefore I like the older processors with a kick ass analog section and balanced outputs. Just my $.02.
The Classe DAC has been discontinued which is why it is selling for such a low price. If you can get a home trial or are not afraid of having to resell it if it doesn't work, then it is worth trying. I was tempted by the Classe's low price, but instead ended up getting a home audition on a Bel Canto dac (which I kept) and have not felt the urge to try anything else since (over a year ago). I have not heard the Classe but I have tried the Rega Planet at home, and the Bel Canto's sound may be to your liking. If you go for the Apogee digital cable, be sure to get the latest version and get at least one meter in length.