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Chord Mojo
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Conclusion
Measured performance
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There are USB and S/PDIF (Coax, Opt) digital inputs. The former uses a microUSB socket and would typically connect to a Samsung phone through a microUSB-to-microUSB cable, that fits their curious dual-socket. An iPhone needs a Lightning-to-microUSB adaptor (£15, $20) with a microUSB cable, or a Lightning-to-microUSB cable. Under test I ran Mojo mostly from my Astell&Kern AK120 digital audio player acting as a transport, connected via Mojo's OPTical S/PDIF input. There's an electrical S/PDIF input too (COAX), through a small 3.5mm jack socket.
    Importantly, Chord do not use the signal-transfer USB for charging. Instead they fit another microUSB solely as a charger input, allowing Mojo to be run and/or charged from an external USB charger/power supply. That can take the form of a phone charger, but I used a smoothed 5V USB power supply unit (£20 from Maplins) for reduced noise.
    There is no analogue audio input, nor Bluetooth for a cord-free link to a phone, or hi-fi as Astell&Kern use. Whilst Bluetooth limits quality to CD standard, it is convenient for mobile use. Instead Mojo must be connected to both phone and headphones through cables, so taking a call is difficult. It's common to use a stout rubber band to hold a DAC to a phone; Chord have machined in narrow grooves at each end of the case for this.
    Under test, the optical input worked to 192kHz from our spectrum analyser, only occasionally becoming intermittent, but 192kHz music files did not play at all from my Astell&Kern AK120 over Chord's own short optical cable. This behaviour is common via optical S/PDIF because the cables and TOSLINK connectors cannot reliably support the data rate 192k imposes. It isn't a Mojo problem.

   Mojo can be used in a hi-fi system as a CD player upgrade, or as a digital preamp; I tried both. As a CD player upgrade it should be turned on with both volume buttons pressed, then instead of remembering the last volume setting, Mojo sets output to CD level of 2V, both buttons lighting blue. The digital output of a CD player is connected to either Coax or Optical S/PDIF input, and a headphone output taken to the hi-fi through a 3.5mm-to-phono adaptor lead. This worked well and offered interesting sonic result – see Sound Quality.
    Another way to use Mojo is to drive power amplifiers direct. It drove a pair of Quad Elite QMP monoblock power amplifiers perfectly. With 4V output Mojo has plenty of headroom. There were no crashes or bangs at switch on or off.
    Chord claim you can run loudspeakers with Mojo (in theory at least it delivers 4W) so we hooked up a pair of massive Tannoy Westminster Royal GRs and it did indeed drive them to a respectable level! Best not to take loudspeaker drive seriously however; trying to drive heavy transient currents into 4 Ohms is not realistic from an internal  battery supply, nor with a charger connected since the output devices would likely overheat and/or current limit/shut down. It's a party trick  – no more.
    And of course Mojo can act as a high quality external DAC/headphone amp for a computer, connected via its USB output, or with Macs via optical for those having an output in the headphone socket. All this highlights the flexibility of Mojo and how it can be used in a hi-fi system, or computer system.
   Mojo's  'Watts Transient Aligned' (WTA)  DAC is unique to Chord and has been under steady development by Rob Watts over decades.   Mojo gets its latest iteration – full strength, not in cut-down form.
    At the press reception Rob told me its digital architecture, and especially the use of a 26000-tap digital filter, allow almost compete elimination of digital noise, which has a repetitive pattern upsetting to the ear. Our measurements show it just managed 125dB as claimed. But what does this figure mean?
    Top quality hi-fi DACs manage around 120dB within a consumer product, our measurements show, with a few exceptions like the Resonessence Invicta Mirus and Wadia di122 both of which exceed 130dB – and cost thousands. So for £399 Mojo is amongst the best, performance wise. When you add to this the fact that it doesn't need a mains supply, its advantages come into focus.



 

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