Mojo Audio Joule V Power Supply

About a year ago I reviewed Mojo Audio’s upgraded Mac Mini music server with its at-the-time newest linear external power supply: the Joule III.

An impressive accomplishment by Mojo Audio, the upgrade turns a Mac Mini into a first- class but reasonably priced music server —with emphasis on a clean, natural, neutral sound (e.g., no ‘coloring’), and it seemed hard to believe it could get any better—after all, I thought, what more could be done with a Mac Mini?

But since then Mojo Audio’s owner, the ever energetic, restless, optimistic and forward-looking Benjamin Zwickel has been tinkering and experimenting with a variety of newer upgrades and peripherals such as a Joule IV power supply, and now the newest one: the Joule V.

New developments in technology are moving digital audio ahead at a rapid pace. For example, serious alternatives to using a Mac Mini as a music server are now out there (Unix based, Linux based) and it is far from clear if a Mac Mini will even be up to par to compete over the next years—or even if Apple will continue to manufacture the Mac Mini. As I found out, however, Mojo Audio is well prepared for these changes. In fact, Zwickel is in the midst of developing alternatives to a Mac Mini as a computer music server (such as a high-performance version of the Intel NUC in a fanless Streacom ST- NC1 chassis). They will be computers specially focused on audio (and video) powered by an external Joule power supply, to be used as a music server but also to surf the web, watch videos, and do all the cool stuff I wrote about in my earlier review with the Mac Mini upgrade.

As I typically do with new technology (such as iPhones), I skipped over the next generation of Mojo’s power supply (the Joule IV) before paying any serious attention. I had hinted in my earlier review that I would not re-visit checking out new Mojo Audio upgrades until the 2016 USA Presidential Election (the Mac Mini can do wonderous complex mathematical simulations/predictions in addition to playing music); but alas, the November 4, 2014 USA Midterm Elections intervened in such a way that I was handed further motivation to carefully analyze and write up my take on the innovations that Mojo Audio has been up to—admittedly, partly to distract me from USA politics for the next two years—thank you high-end audio!

I had heard the Joule IV with Mac Mini at the recent New York Audio Show 2014 on a system with astounding sounding 7-feet-tall speakers: the new Alta Audio ‘Statement Tower’ that weigh 485 pounds each and retail for $200,000 per pair, and I must say, it was entertaining to watch reviewers and other audiophiles walk into the room and scratch their heads trying to make sense of just where the hell was the digital media being played from with such great sound.

But what really caused me to pay serious attention this time around (Joule V) was that although similar in size to the Joule III (and Joule IV) this new Joule V linear power supply is heavier in weight: Some serious new engineering had taken place. It now offers the option/ability to power two sources at once (e.g., it has 2 regulated outputs) such as two Mac Mini, or one Mac Mini and a large external hard drive, a C.A.P.S Zuma music server, a JPlay or SOtM high-performance USB card, a professional grade NAS/RAID system, and even the routers used to interface with them: two XLR power outputs are an option on its back instead of only the one in the earlier models, and these outputs can handle (together as total) 10 amps continuous (in any combination summing to 10), and can go up to 20 amps for short periods of time. Finally, the Joule V has a power switch on the back; the earlier models do not. I got to briefly see and hear the Joule V in action in the Mojo Audio show room at the recent Rocky Mountain Audio Fest (RMAF) 2014, and I was sufficiently impressed that I inquired if it would be possible to review it (the ‘basic black’ with 2 outputs). Zwickel kindly agreed; I was very eager to hear how this new upgrade would sound on my own system in comparison to the Joule III.

Mojo Audio Joule V Power Supply rear (in black).

Mojo Audio Joule V Power Supply rear (in black).

In preparation for my review, I asked Zwickel to describe what was ‘technically’ special/new about this Joule V and this is what he said:

‘The low-noise regulator has been upgraded to a Belleson SPHP ultralow-noise, high-dynamic regulator with less than 50uV of peak-to-peak ripple and less than 10uS recovery time from zero to full power output. Belleson actually worked with us on the initial development of their SPHP regulator and we were the first company to use the SPHP in a commercially marketed product. We continue to work closely with Belleson on further refining the SPHP as well as other beta power supply products we will be using in our 2015 line. As you know, we co-exhibited with Belleson at RMAF ’14.

The grounding was changed to a hybridized plane/star schema with the star node on the output and an optional AC ground lift.

Though we always heat sunk our parts to the exterior of our chassis, the Joule V chassis has been reimagined with three internal exterior heat panels and 50% thicker aluminum to more uniformly transfer and dissipate the heat over the entire chassis surface. This not only allows the Joule V to have 33% higher current capacity, it also keeps all the parts at roughly 33% lower temperature significantly lowering thermal noise and extending parts life.’

A serious upgrade indeed. And the prices are the same as since 2010. Mojo Audio even allows a very reasonably priced upgrade of your older Joule models: A fully warrantied power supply upgrade that includes the labor for installing SSD, RAM, optimized OS X, and player software at only $199.95. Moreover, they even offer new impressive options: Your Mac Mini can be fitted internally with two Solid State Drives (SSD) at once; one small SSD one (128GB, for example) to hold the system software, and then a 1TB SSD dedicated for holding your ‘highest quality’ music files; your ‘lesser quality’ files are to then remain on an external hard drive connected to the Mac Mini (via firewire or USB). And of course these choices are your own and you can always move files back and forth among the internal and external drives at your leisure.

I already had a small 128GB SSD installed on my Mac Mini for system software, so I asked Zwickel to additionally internally install the 1TB one dedicated only for music. My purpose was to compare the sound quality of playing my music files from an external hard drive (using Mojo Audio’s proprietary powerless firewire cable) as I have been doing for some time now, to playing them directly from the new dedicated internal 1TB SSD drive. Most modern high-end music servers (typically costing considerably more) indeed use large internal SSD drives dedicated for the music files; but even they usually use that same drive for system software. There is good scientific justification for two separate internal drives; Zwickel explained to me why this is important for optimal sound quality from a music server:

‘Having dedicated data paths is actually more important than the speed of the CPU, amount of RAM, or other system resources. The three types of data (media in, media out, and software commands) should travel down dedicated pathways using dedicated data controllers. When the same data controller is used for different types of data the controller has to act like a traffic cop directing traffic around something – data of all types but one are stopped to allow a small amount of data of another type to pass, and then this process is repeated so that each type of data can pass through the bottleneck of the one data controller.’

In addition, internal drives for playing music have lower latency for software commands (start/stop delay) than external drives. In short: a dedicated internal SSD drive for playing music has strong practical/engineering justification for helping make sound quality better. And as we shall see, my ears agreed too.

Mojo Audio also alerted me about (and sent me for inspection) a new high-end dead-quiet fanless external hard drive that they now offer to be powered by the second input of the Joule V, and which could connect to the Mac Mini using Mojo’s powerless firewire cable: An ‘OWC Mercury Elite Pro’ enclosure ($99.95 ) that Mojo offers with their option of internal resonance dampening treatment and Sorbothane feet (an additional $99.95) and then a variety of drives to go in it (you choose). You could, for example, put in the 1TB Apple drive that is removed from your Mac Mini, or go for a 3TB or even 4TB 3.5” Western Digital AV-GP HDD. The drive enclosure is a sleek modern looking heavy extruded aluminum one. For power, it connects directly to the Joule V with its own separate black Mojo cable. I will not be reviewing this in this review, suffice to say it is quite something.

The sound

The Joule V offers a very significant improvement in sound over it’s earlier generations. Only a handful of examples are needed to articulate what I mean, and I will do so next, and then give a summary.

Fleetwood Mac. Shortly before I had the Joule V, I had been listening carefully to the Fleetwood Mac album ‘Rumours’ (1977), but in two formats: a ripped CD from their remastered 2004 version, and a 2011 release in 24/96 FLAC that I obtained from My young daughters when first hearing the first track with me, ‘Second Hand News’ had so quickly started dancing and bouncing about the room that I became fascinated to listen more seriously to an album that I admit I totally ignored when it first came out in 1977. (I recall (vaguely) thinking that the drumming sucked, and as a drummer then (1970s) I chose to foolishly ignore the entire album.) I now quickly took to the wonderful acoustic track 3, ‘Never Going Back Again’. It won me over, and my daughters loved it, too. And then there was the classic track 4, ‘Don’t Stop’ used by Bill Clinton as his theme song to help promote his successful 1992 bid for USA President.

The details now exposed in ‘Second Hand News’ together with a remarkably clean neutral sound and astonishing attack and decay of the plucking on the guitar as presented by the Joule V was very noticeable; beautiful. However good the Joule III was in comparison, it was blown away by the Joule V. The 24/96 version of Rumors was best, and although Zwickel (a noble and mighty proponent of the suffciency of 16/44.1 resolution—a notorious minimalist) might disagree, I say the following (as a compliment): This music server when playing very finely recorded/mixed 24/96 recordings as compared to a Red Book CD can dazzle at times, and this is an example.

Piano: Fazil Say, ‘Mozart: Piano Sonatas and Variations’ (1998) CD. Mozart’s 12 Variations on the 1761 melody ‘Ah, vous dirai-je, maman’ K.265 is a piece that uses the same melody found in such children’s classics as ‘Twinkle Twinkle Little Star’, the ‘ABC Alphabet Song’, and ‘Baa Baa Black Sheep’ nursery rhyme. As such it is a piece I can and do enjoy together with my young children. I greatly favor Fazil Say’s lively fast-paced performance with its enthusiasm and energy. The Joule V made his piano sing. A tighter more focused sound with snappy acoustics of the attack and a nice lingering decay of the piano keys were vividly on display with the Joule V.

Cello: Janos Starker. Recently I attended a gala event in which–as a side event as you walked in–were four wonderful cellists performing classical pieces in a nice homey and small part of the venue (which was the huge Cathedral of Saint John the Divine, near Columbia University in New York City). I stood right in front of them as close as I wished while most people walked right past–without even listening—on to the open bar (Yes: I did go the bar later, returning with a wine glass in hand to listen some more). I wandered back and forth (with my wife) from the left-most cellist to right-most cellist listening and admiring the gorgeous sound. Nothing like that can truly come from an audio system, right? Since to me the sound of cello is divine, getting my system to yield that live sound is what I have been aiming at for some time now, and as an audiophile I have been trying to close the gap to within ✏ (‘epsilon’), meaning (mathematically) as tiny a difference as possible. The Joule V brought me as close as I have ever succeeded.

As a main reference (among others) I used the classic CD from Mercury Living Presence, ‘Bach Suites For Solo Cello’ with the extraordinary Hungarian-American cellist Janos Starker (who died recently, in 2013). This recording from 1964 had been suggested to me by Audiophilia’s Editor Anthony Kershaw a while back and I am grateful for his recommendation.

What role did the new internal 1TB SSD drive play in the improvement of sound? Using the internal 1TB SSD drive made my speakers sound ‘faster’, because attack was quicker and the delay more natural. Time and tune were better. It must have been the lower latency for software commands (start/stop delay); but I can’t be sure if that is the only reason. The Joule V improvement in sound is quite significant, providing the lion’s share; but the very simple change in what drive is used to play the files handles the latency adding icing on the cake.


The new Mojo Audio Joule V Mac Mini upgrade with a dedicated internal SSD drive yields a significant improvement in sound quality from their earlier models which already are outstanding: increased dynamic range, a larger soundstage, impeccably clean sound at all ranges with dead-quiet quiets and tightened punchy bass; the timing of attack and decay of percussion (cymbals, drums, plucking of acoustic guitar strings, piano) faster and more natural. The sound quality was downright uncanny at times (check out, for example, the live (2005) album EAST WEST (WEST) by Bill Frisell, and wander around your listening space as it plays). After all my testing I truly felt that a ‘traditionally’ important main component of my system had been upgraded with something expensive (speakers? DAC? Amps?….); but no.

In general, audiophiles talk about getting that last “5-10%” increase in sound quality from a given device–and usually at great expense; I think Mojo Audio has probably succeeded in closing the gap here in the realm of inexpensive music servers – at minimal extra cost from its earlier models. I would stack this new upgrade against any music server even higher in price. It’s a bargain. Mojo Audio surpassed my expectations with this. And for sure I now have a most pleasant reason to ignore the next 2 years of USA politics in favor of listening to Fleetwood Mac, J ́anos Starker on cello–or even children’s music (Mozart!) with my young daughters. The Joule V setup gets my highest recommendation.

The Mojo Audio Joule V Power Supply

Manufactured by Mojo Audio

3501 Vail Ave. SE, Unit C, Albuquerque, NM 87106

Tel: 949.GET.MOJO (949.438.6656)



Prices: Joule V in ‘basic black’ w/ one regulated output = $999.95; Optional 2nd regulated output = $250;

Optional machined/anodized face plate = $199.95

DC power cables start at $99.95

Source: Manufacturer Loan