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Positive Feedback ISSUE 79
Your Final System (YFS) PS-12m Mac Mini Power Supply/
Internal Power Filter Mod
If you're an audiophile, you realize at some point that digital spinning discs won't be around forever. Although that realization hit me several years ago, it took quite a while before I really decided to get serious about a digital source based on a computer. I'd heard several computer-based rigs at shows, and what I heard was promising. But, to get there from here it would require some serious investment of my precious time, and after working with computers all day I usually don't want to spend my free time with them. Until now. The last few years listening to silver discs just wasn't doing it for me. More and more, until almost exclusively, I turned to vinyl using my somewhat modest analog setup: VPI Scoutmaster, Sumiko Blackbird (mod by Soundsmith), and Ray Samuels battery-powered F-117 Nighthawk phono stage. These three play very well together, and really deliver. Although not perfect, they make me happy. Very happy. But I do own a collection of CDs with great content, most of which are not available on vinyl. And although I do still listen to them, Redbook playback through my Ayre CX-7eMP was leaving lots of great music unfulfilled. But if I was going make a major change to my setup, and invest time and money, I really wanted to harvest more from the CDs then I was currently getting. Beyond that I wanted to be fairly sure that DSD could be a player in the new rig. The search began. The DAC came first. After listening to several at shows, and getting some recommendations from friends with trusted ears, I narrowed it down to a few choices within my price range. Not wanting a strictly neutral unit, I was looking for something with a full textured sound that could also support DSD. The Mytek Stereo 192 DAC seemed to fit all my requirements. After an excellent recommendation from Wojciech Pacuła, the editor of Poland's High Fidelity, my choice was confirmed. The Mytek it was. Now the hard part began. So many computers and so many software playback applications. It's a little daunting when you first start out. I'll spare you most of the details. Turns out I ended up buying the hardware based on the software I chose. Since my main goal was to resurrect my CD collection, I chose Amarra for Redbook playback. Out of all the applications I listened to, it was the best to my ears at mining goodness from 16/44 files. Going with Amarra narrowed down my hardware choices considerably. It only works on a Macintosh OS. Although I use a Windows box for my other chores, I had no problem going to the Apple side. Since I hadn't owned a Mac in many years I wasn't in tune with their lineup, but the choice for me became clear quickly. The Mac Mini. A very stylish little box milled from sold aluminum that I could leave on my rack and control remotely from my iPad. Since I wanted to future proof as much as possible I maxed it out: 2.3 GHZ Intel quad core i7, 1 TB SSD fusion drive, and 16 G RAM. For more storage, a 2 TB Thunderbolt RAID @10K RPM.
Nice as it is, the Mac Mini has an Achilles heel. You guessed it, the power supply. I've read quite a few articles testifying to the havoc this cheap supply can wreak. Mixing high quality music and an inferior power supply just doesn't work. That's when I came across a blog by Paul McGowan, the P in PS Audio. I certainly respect Paul's opinion, so when he mentioned a power supply mod for the Mac Mini from a company known as YFS or Your Final System, I jumped on it. Within minutes I was talking to Kevin O'Brien at YFS in Boulder. Great guy. He patiently answered all my questions about the power supply mod, and his passion was really apparent. I got a very good gut feeling from the conversation, and it didn't take me long to make up my mind. YFS know their way around a power supply. What does the mod include? At a high level they do three things: Remove the old power supply, build a new, custom high-current power supply, and install filtering in the Mini for the DC. The power supply is hand built in New York, but you have to send your Mini to YFS in Boulder, CO to complete the integration. This is a 12V/ 7.5Amp DC linear power supply with an 18" umbilical that attaches to the rear of the Mac Mini via a 2.5mm DC barrel jack. YFS removes the internal switching power supply and replaces it with high quality silver leads straight from the Mini motherboard fed into a high quality internal power filter, then to a 2.5mm x 5.5mm DC power jack on the Mini rear panel. YFS says they actually supply more current (7.5 amps) than the stock Mini switching power supply which is rated at 7.1 amps. That's the reason their power supply is big and vented for heat – like a linear power supply should be. According to YFS: "Our power supplies are built from scratch, by hand, in Upstate NY and carry a 1 year warranty. We don't source our products from distant off-shore locations and then assemble them in the USA. We're not saying there's anything wrong with that, but we feel our customers deserve much better quality. Again, our products are entirely hand crafted in the USA. We stand behind our products and each and every PS-12m is made to order". I sent my DAC along to YFS as well for a full integration check, and then went off on work travel for a couple of weeks. Upon return, and after unpacking the Mini and the power supply, I had to admire the build quality of the power supply case and brushed aluminum front of the supply. It would have no problem fitting in visually with the Mini and the other components on my rack.
I connected the PS-12M umbilical cord to the new connector on the back of the Mini, and also connected USB from the Mini to the Mytek. For now, I also had a monitor, mouse, and keyboard hooked up, although I planned to control everything remotely with an iPad once the kinks were worked out. Now it was time to try to play some music. The trial version of Amarra was loaded, and Kevin had left a few tunes on the mini. I was surprised when I opened Amarra, clicked on some Pink Floyd and got music, although it didn't take long to realize that something was wrong. Music was playing, but it was unlistenable. After trying to troubleshoot this myself, I finally realized I didn't know the software or the OS well enough. I called a friend who is experienced with Amarra, and we got things right straight away. Because all volume controls were not at maximum there was some dithering going on which is highly unpleasant. Once fixed though …nice. What I heard then was a reward for all the research, time and sweat I put in on this project. The effect of the YFS mod was impressive. Music emerged from a silent background. The flow was so… smooth and relaxed, yet with a compelling forward momentum. Organic and detailed, very un-CD sounding. Lush textures with an addicting smoothness so atypical of 16/44. I've heard very similar setups (Mac Mini and Amarra) at shows before, but never with the YFS PS-12m. It was easy to hear the bass tighten up with visceral slam. Deeper, taller, and wider soundstage, instruments and voices with more bloom. I was hoping for improvement, but I hadn't expected this much. Kevin also sent along a YFS "data only" USB cable. Obviously very well built, this cable eliminates the power lead to maximize data integrity by minimizing waveform distortions in the transmission link, and was a crucial factor in getting unadulterated bits and bytes from the Mini to the DAC. Once I loaded in a few more discs I spent hours listening to albums I knew well. Familiar music yes, but the experience was so different. Low level dynamics were a huge improvement, and were present in a way that gave new meaning to my old friends. The distinct shading of nuance connected me with the music in a very special way. The rich presentation and bloom around individual instruments and voices gave them their own special space, where before they were skewed together. The scope of detail when listening to orchestral music was staggering, and facilitated a listening experience that was pure pleasure. Once I was satisfied (to put it mildly) with the quality of Redbook playback, I needed to find a tool to perform the best possible conversions and help me to organize my library. Although there are plenty of freebies out there I found that I liked dBpoweramp the best for conversion, metadata, and organization. It embeds your metadata and album art instead of just associating it. So—when you want to move your library your metadata and art goes along. What about DSD? Well, when I found out that Amarra "plays" DSD by converting it to PCM, I thought to myself, "what's the point?" After a little more research I ended up using Audirvana for DSD playback. It has a very user friendly interface, (I think it has a much better look and feel than iTunes) and plays DSD without a hassle. After spending some time with both Amarra playing Redbook and Audirvana playing DSD my impression was that the system was consistently giving me excellent results: A smooth, non-fatiguing presentation that was a pleasure to listen to, with a natural presence and flow uncharacteristic of my past experiences with digital playback. There was a sublime delineation of space and realism across the entire soundstage. Dynamics were outstanding, with impact and weight that didn't obscure. Perhaps the change that drew me closest to the music was the sense of momentum and flow that kept me engaged and drawn in to the essence of the performance. Maybe my thought about CDs and digital playback in general has been wrong all these years. Maybe bits and bytes are not the devil. Maybe we just didn't have the right means to coax goodness from these files. Until now. Does the Mac Mini/YFS mod make me as happy as my vinyl? Well…no. But it makes me happier than any digital source ever has by far. The effect of adding the YFS Power Supply and Power filter mod to the Mac Mini is like a supercharger that gets me a long way to the goodness of vinyl. If you have a system like this, and want the very best from it, YFS will help to take you to the pinnacle of what computer-based audio is all about. I'm a guy who always, always looks for value. Several friends that I've mentioned the YFS mod to thought that the prices for the PS-12m Linear PS and the Internal Power Filter Mod were somewhat exorbitant. I thought so too at first. Then I got to listen to the results. Now? Worth it. Every penny. YFS PS-12m Linear PS $1895 YFS Internal Power Filter Mod $650 ($275 self-install) YFS 1m Data-Only USB Cable $350 Kevin O'Brien - [email protected] All images courtesy of Your Final System
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