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Positive Feedback ISSUE 72
march/april 2014

mojo audio

Mac mini Music Sever

as reviewed by Al Chieng

I have always felt that when addressing an upgrade to my audio rig less is more. What I mean by this is that performing an upgrade takes careful thought and planning, and for me at least, is incremental. This incremental boost is for several reasons. One of the main ones is cost, but more importantly I always find it hard to pinpoint "change" when more than one component is switched in the audio chain. Recently, I found myself in that scary but exciting realm of can I make this any better? Cue my current music server. My digital front end consists of an Apple MacBook which has been a stalwart for many years. The all-in-one nature of the laptop was a definite strength as it runs nearly silent, can be upgraded to certain degree when the need arises, and is supported by a strong enthusiast crowd. One area of concern for me was, although the laptop is easy to tweak software wise, they are a lot harder to upgrade hardware wise. Running more ram intensive media players showed the age of my laptop as I eventually could no longer upgrade the ram.

Checking my email I decided to take up an offer to review a product by a company called Mojo Audio. Before you immediately connect the name with that popular movie, the name according to owner Ben Zwickel, is derived from a protection against voodoo. Thus, Mojo Audio was born on according to Ben, "simple physics and affordable pricing." A little background on Mojo Audio from Ben himself:

The creation of Mojo Audio was more serendipity than intention. I was disabled in a car accident and could no longer run my computerized embroidery business. I went back to school to get a degree in Computer Electronics Engineering Technology with the hope of working part-time as a bench tech. As I was selling off my collection of vintage electronic components on eBay to get some money for school, I figured I could get a bit more cash by selling cables made from NOS Western Electric wire as opposed to selling the wire by the foot. I also figured I could get more doing upgrades to the vintage CD players from my collection before selling them. I knew the products I was selling performed better than most mainstream audiophile products, but I had no idea the response would be so strong. As I was finishing my first semester at electronics school, Mojo Audio sales were so strong I was hiring fellow students to work for me.

Prior to Mojo Audio, I had decades of electronics and computer experience. Back in the late '70s, I started my DIY audio hobby as a broke college student restoring and upgrading old Dynaco tube amps. After college, much of my career involved consulting for computerized processes in soft goods manufacture. Interestingly enough, my DIY audio hobby came in quite handy when I was a manufacturing consultant in Mexico and the Caribbean. To resolve problems running modern computerized equipment, I had to re-engineer the power supplies so that they would work with the inconsistent AC power that plagues developing countries. So you could say I've been professionally modifying the power supplies on computers since the early '80s.

Apple computers in general make excellent media servers. Partly this is because Apple uses high-quality parts and partly it's because any Apple computer can run any operating system, use any player software, and play any file format. The Mac mini is specifically well-suited for a power supply upgrade since it uses a single-voltage power supply and has no integrated monitor, track pad, or keyboard to add unnecessary electrical noise or mechanical resonance. Among the other advantages, the Mac mini has a compact, machined aluminum chassis that is extremely well-shielded, both mechanically and electronically.

Originally the Mac mini had an external "white brick" switch-mode power supply (SMPS). For our prototype, we simply replaced the stock SMPS with a basic low-noise 18.5VDC linear power supply we built from spare parts we had sitting around our shop. At the time, Mojo Audio was in the business of upgrading high-end transports, DACs, and CDPs. Even this simple implementation of a 2007 Mac mini with a linear PSU performed better than any transport I'd ever heard, regardless of size, price, or topology. Needless to say, a few days later my beloved CEC transport was for sale on Audiogon, and Mojo Audio was in the computer media server business.

In 2010, Apple changed from an external "brick" SMPS to a small 12VDC internal SMPS that took up about 25 percent of the chassis. To upgrade the PSU on Mac Minis manufactured 2010 or later, the stock SMPS must be removed and bypassed before an external linear power supply or battery can be used. In 2010, we made the first of our Joule series of PSU (named for James Prescott Joule, the physicist), and the first generation of our Internal Filter Module (IFM) was born. The IFM fills the space where the stock SMPS used to be. Our fully shielded, hardwired DC cable system was developed in 2011 after we learned how much RF noise can actually enter the chassis of a Mac mini through the wires and connectors of an external PSU. This is the main reason we don't recommend using the unshielded Power Con or 5.5mm barrel jacks with DC power cables, unlike many of our competitors.

Our goal was to create a high-performance computer media server solution that was versatile, durable, and economical, with both a turn-key and DIY option. We approached this goal by both minimizing mechanical and electrical noise that cause bit read errors and maximizing system resources through data pathway and operating system optimization. Our new powered external drives with powerless data cables play a big part in optimizing data pathways, maximizing system resources, and minimizing bit read errors.

From the first generation, our Joule PSU has been an exercise in overkill: it has always generated more than twice the current a Mac mini requires while generating less noise than a LiO4 battery. The spread spectrum capacitive and inductive filtering we use in both the AC and DC filter stages of our Joule III PSU reduces noise well into the gigahertz range needed by modern computers. The latest version of our IFM has more than -70db of noise attenuation in the four main wireless frequencies that marinate our world, Wi-Fi, Bluetooth, Cellular, and FM. Combined with our fully-shielded, hardwired DC power cables, our current PSU upgrade delivers less than 15 percent the noise of an LiO4 battery, with 7.5A continuous and 10A peak power. That's more than enough current to power a Mac mini plus additional devices, such as external drives, USB converters, and DACs.

Having spent decades in product development prior to Mojo Audio, I considered several factors while engineering our PSU upgrades. Since durability was as big a concern as performance, the thermal properties of the Joule III were optimized as part of the circuit board design. All the hot parts were heat sunk to the outside of the chassis, with 70 percent of the heat leaving through the faceplate. This both removes heat from inside of the chassis and creates a thermal current that actually draws heat out from inside any rack or cabinet it sits in. This design nearly doubles the life of component parts inside our Joule III.

We even engineered the chassis size/shape to fit in a USPS Priority flat rate box, allowing our PSU upgrade kits to ship internationally at a reasonable price.

While trying to keep up with the overwhelming demand for our Mac mini upgrades, we have left one aspect of product development incomplete, which is the documentation. For 2014, a majority of Mojo Audio's development budget is going into more FAQs, how-to guides, and blogs. This info, which will be available for our customers and audio fans in general, will explain both how to maximize computer audio performance as well as illustrate how the products we sell can be implemented in the ever-changing world of digital media. Beyond that, I plan to spend time doing the two things I love best: listening to music and R&D.

All contents were shipped promptly and packed with care. Mojo Audio is an outfit that is more concerned with its product versus flashy packaging or presentation. The Mac mini server was sent with the PSU upgrade, Firewire cable, and 2.5 inch dual bay raid enclosure. Right away I saw the attention to detail as all of it connected together quite nicely and seamlessly; the only small hiccup being the sequence of how to connect the Firewire cable with the rest of the system. A quick email resulted in the original Firewire being replaced with a new version developed by the company. Ben has stated that the majority of the company's time has been spent fulfilling orders on its media server lineup… so proper documentation will be available to customers later this year; translation: some media smarts are required for the initial installation and getting it all together.

What I would recommend is running initially a traditional keyboard, mouse, and monitor setup to get all your software and settings properly tweaked, and then run a simple remote app to access your media server when needed. After the initial setup it was smooth sailing to operate the Mojo sever with the remote app of my iPhone or iPad. The major strength of the platform became evident as using the Mac mini allows for a very flexible platform to load any number of different media players, plugins, and devices to maximize the playback. The comparison between my MacBook and the Mojo server took place using the standard iTunes and Audirvana.

What do you get for your money? I embarked on my quest by playing "Don't Leave" by Norwegian singer Ane Brun. The song was recently featured in a car commercial and her singing style is quite unique. Playing the song through the Mojo server was definitely a treat as the presentation of folk and adult contemporary music was conveyed in a very intimate way. Ane took front and center which improved upon my previous setup in terms of a darker background between notes. I suspect the improved power solution provides less interference and results in a quieter background. Out of curiosity I played the track both directly from my NAS (Network Attached Storage device) wirelessly and from the SATA portable hard drive. The track sounded beautifully from either storage device with little audible difference between the two. Hearing the strength of female vocals with the server led me into trying some Bonnie Raitt and "I Can't Make You Love Me" from her very successful album Luck of the Draw. I find this song to be sometimes system dependent; to draw out emotional connection between the heartfelt lyrics and the singer can be daunting. Raitt has said it herself that although she enjoys performing the song on a regular basis the range necessary and the emotional toll it takes can be draining. Another improvement the server made was increased depth and width of my sound stage. Orchestral works such as Cesar Frank's Symphony in D Minor performed by the Philharmonic Orchestra and conducted by the great Carlo Maria Giulini profiled this enhanced sense of space. I could hear the subtle nuance of his conducting throughout the piece and the connection and interpretation of his direction on the music. Overall, the server had an uncanny way of increasing the resolution of all the music I threw at it.

What additionally do you get for your money? Well, not only is the Mojo Audio server a music playback device, but it can also be used as a very competent media server. For those that need an all-in-one device, Ben picked an excellent transport to stream all kinds of different media. The flexibility is basically anything that is being produced for the Apple platform and for those that know a thing or two about computers in general you can also go cross platform in supporting Windows and Linux based applications. For example, when not listening seriously to music the server can be used to watch Netflix or used as a go between media server to watch movies on my iPhone while away from home by accessing my NAS.

Who is this product for? Well, I believe that if you are ready to replace an aging transport with something that provides media flexibility, then this is your product. What Mojo Audio has done is introduce a product that has the ability to be upgraded when the need arises. One advantage of using a server like this is the software possibilities. I like to think of it as having my iPhone doing my in-car navigation. I know that the user interface and maps will be continually updated as the need arises. More often than not the in-car systems offered by car manufacturers are not up to par and are expensive to upgrade. Ben has created an audio device for a mass audience that has the potential to be very intuitive and customizable. This simple example means that you are not going to be stuck with an aging audio device but something that has real longevity because the platform will be supported for many years. The entire package that I was provided can be bought incrementally as the need arises; perfect when the itch comes back and we need to scratch it. For those that own a Mac mini the proposition becomes even more attractive as Mojo Audio can perform upgrades on your existing machine. If you are a current Mac mini owner I would first go with the power source upgrade and see where your budget goes from there. For those going in new, you can purchase a Mac mini and send it to them or purchase an already modified one from the company. Checking out the company website Mojo provides a number of additional upgrades such as storage solutions, cables, and even an isolation platform.

In the end, Mojo Audio has put together an outstanding product by deciding not to reinvent the wheel. Instead it chose a very competent product and made it even better for the audio enthusiast while keeping the functionality of the Mac mini intact. My listening notes indicated better separation of instruments, lower noise floor, and better imaging. The server was a definite improvement over my previous transport, and as this product matures I am confident that it will be more user friendly for those that are not technologically savvy. While I found it more convenient to connect the server to my NAS, I can definitely see the benefit of using the attached hard drive option. This option would give you a fully independent music server that is self-contained with a small footprint. The advantages of solid-state music playback have been reported in many articles and the Mojo Audio server could be utilized in this way. No moving parts means less mechanical interruptions, less power consumption, and less heat. The hybridization of technology is definitely exciting and Mojo Audio is at the forefront of providing a true media server solution. Give it a shot as this product has some serious mojo. Take care. Al Chieng

Mojo Audio Music Server

• 2.6GHz i7 quad-core Mac mini.

• Joule III power supply.

• Internal Filter Module. 

• Hardwired DC power cable.

• 2nd hardwired DC power cable to power external drive.

• Oyen Digital MiniPro RAID w/ stock Apple 1TB drive removed from mini Installed as back up and 1TB Western Digital AV-25 drive for play.

• Powerless Firewire cable.

• Atomic Audio Platform.

Approximate Retail: $3049.75

www.mojo-audio.com

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