Several months ago, I reviewed the Meridian 518 digital processor/preamp for Soundstage! Quite honestly, I fell in love with it. It's a marvelous piece of equipment. And if you take a little time to read the review, you'll know that it does a lot of wonderful things (check out the Talkin Shop Archives for Marty's review).
To quickly recap, the 518 is many things. It's a full digital-domain preamp. Plug your transport into it, send your outputs to your DAC, and your DAC's outputs to your amp. Do all of this and what you get is a de-jittered signal stream sent to your DAC with full digital volume control. It's a nice simple signal path and eliminates your need for a regular preamp, while giving you very good sound.
Or it's a resolution enhancement device that will de-jitter the transport signal, let you adjust the digital noise-shaping and digital gain, and adjust the input and output digital word length. In this case you would use a regular preamp before your amp for volume control, but who cares, the sound you'll be able to coax from those little silver discs is worth it. Really. Read the archived Soundstage! review for more details about the 518 and then test drive one for yourself. I still whole heartedly recommend it.
In fact, the only thing that's holding me back from buying a 518 is the plain, rounded box on the shelf below it - the Audio Alchemy DTI Pro32. Okay, so the Meridian's a better looking piece of equipment on the Solidsteel rack, but hey, the DTI Pro32's not that bad. Besides, who cares how they look. It's the sound that matters.
I spent several weeks with each of these units - listening to them by themselves, and as well, in crazy, haphazard, wholly unscientific A-B comparisons. And what did I find out? Well, I'll tell you. I'm not going to beat around the bush and make you read the whole review. No I'm not. In fact, I'll tell you to your face that, sonically, the Meridian 518 and DTI Pro32 are each wonderful examples of audio engineering. And each a major contribution to the advancement of digital audio. And by the way, this is not a "cop-out."
In all of my listening tests, one constant was my preference for "enhanced" digital sound, be it from the 518 or the DTI Pro32. Both boxes are able to take a cold, dead-sounding CD and give it life. Whether it's from the jitter reduction that both units provide or the "resolution enhancement" provided by both, I couldn't say. But time and again, both units amazed me (and my wife) by being able to coax near true-to-life music from my system.
The DTI Pro32, in a manner similar to the 518, allows the user to enhance the digital signal in a number of ways. One is by allowing you to adjust the stream of digital bits being sent to your DAC. This will allow you to send a 20-bit word length digital signal to your 20-bit DAC. The DAC does its work more efficiently and recovers more of the signal, thus sounding better. At least in my experience, this has proved true. The DTI Pro32 also allows the user to adjust the phase of the signal. These features are included on the 518.
The DTI Pro32 offers a little something that the 518 doesn't (at least not now) and that is HDCD decoding. Aside from the ability to change the word length stream, the DTI Pro32 will also decode HDCD discs (when HDCD is processed, all resolution enhancement is turned off). If you have HDCD discs and enjoy the sound from HDCD (which I do) then this is a big plus.
Well, now that I've established that they both sound great and do great things for digital sound, who wins? That depends on what you need and what your current system is. My own preference is for the Meridian 518. Sonically, the two are so close that the only thing that seems to really separate them are their features.
Let's start with my needs and my current system. I like the 518 over the DTI Pro32 for several reasons. First off, I have a Meridian 563 DAC and the 518/563 combo sounds and looks great together. Secondly, the 518 lets me do more things to the signal. I can tweak the digital gain before it gets to the processor. This is necessary for some older or poorly pressed CDs. In fact, the 518 can do everything that the DTI Pro32 does and can also be used as a digital processor to make home CD's. The 518 also has a better user interface. It's display tells you exactly what's going on and what the settings are. The DTI Pro32, by contrast, forces you to rely on your memory (or the owner manual) to understand what the LED's are telling you. Lastly, in a pinch, I can get rid of my preamp and go with a real basic streamlined system, transport-to-518-to-DAC-to-amp-to-speakers. Very nice.
Is the 518 for everybody? No, it's not. If you want HDCD or have an Audio Alchemy transport with I2S interface, then you'll want to have the DTI Pro32. From what I've heard with my own ears, I2S is very cool and a better digital interface than the current standards. The DTI Pro32 is also a few hundred dollars less than the Meridian, so if you're happy with your preamp and don't want to make recordings, you would be very happy with a DTI Pro32.
Also, if you're someone who likes to tweak your system by changing and upgrading components, Audio Alchemy may be for you. The company is constantly upgrading it's products to bring you better and better sound. You can get into the DTI Pro32 and try different power supplies and have fun playing around.
So, I'm going to call this contest a draw. My only advice: Go out and audition the 518 and the DTI Pro32 for yourself. Listen to the magic they bring to the music. And let me know what you think. I'm sure you'll find, like I did, that they are both winners in the digital world and well worth your serious consideration.