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Review and Measurements of Chord Mojo DAC and Amp

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I own a Topping D10 and a Chord Mojo, using the optical out of the D10 it's possible to feed both Dacs the same signal. I plugged them both into a Naim Nait5si and switched between them whilst music was playing. Once level matched I could not discern any difference whatsoever, no matter what music I played.
One thing re this review though: I've read quite a bit of Rob Watt's postings on the Mojo, and I get the impression it's somewhat sensitive to noise from both USB signal and USB power. I think that it was initially designed to be used via battery power and with the signal coming from something like an iPhone/iPad which supposedly has very clean USB signal vs a PC. I usually use mine connected to a MacBook via the optical and I *think* it sounds a bit better than the USB, but I'd love to see measurements to confirm/deny this.
 

graz_lag

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... I think that it was initially designed to be used via battery power and with the signal coming from something like an iPhone/iPad which supposedly has very clean USB signal vs a PC ...
I confirm you that the supply from a battery vs. from the laptop USB port thru the USB cable may add quality in the sound restitution from a DAC.
I have in my secondary system a Korg DS-DAC100, which gets power via USB only.
What I did is a simple modification to a "Y" USB cable with two "A" connectors, where one connector (A1) was originally wired for both power and data while the other connector (A2) has just the power supply wirings.
A2 feeds the DAC from a RAVPOWER 20,000mAh battery, A1 feeds the "data only" from the laptop.
I have "unsoldered" pin #1 & pin #4 into the A1 connector so that the power path from the laptop is cut.
The better performances of this configuration vs. the standard one, although using a $50 USB cable from Supra of Sweden, has been confirmed by my family members and friends as well.
A good practical advantage is that the RAVPOWER battery can be kept fully charged from the main during it's operation, so I assume it can supply a very constant 5V to the DAC.
I have chosen RAVPOWER vs. other battery brands because of the their claiming abt. the << ismart+ >> outgoing tension and power circuit regulation.
I find this installation as simple, economical and efficient.
 

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amirm

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I usually use mine connected to a MacBook via the optical and I *think* it sounds a bit better than the USB, but I'd love to see measurements to confirm/deny this.
I am on the road right now but when I get back I can try this.
 

amirm

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Amir,

I have enjoyed reading your forum for the past several months, and I finally joined tonight after reading the Chord Mojo piece. I love what you are doing, and I wish I had the gear you have so I could test some of the digital components I've had over the years.

But I'm a bit torn by your findings, and I do own a Mojo. There is no doubt that your measurements show a product that is reasonably well designed, that does come up a bit short when compared to the measurements you've observed for other products. But despite the middle-of-the-pack measurement performance, I find that it sounds superb as a headphone amplifier.
I want to be clear about middle of the pack performance: the distortions in Mojo are below that if 16 bit audio. So its performance should be transparent for mass majority of content and everyone who listens to such just the same.

The unit is also pretty powerful and that is by far the main impression that is left with any listener.

The point of the review here is to check on technical superiority of the design because that is what Rob advertises. Certainly reading his posts one thinks that it has better measured performance than any else. Alas, that is not true and this is troublesome when he charges two to three times more money than competing products.

So no one should be disappointed in the fidelity they get with Mojo. That is not being put down.
 
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To add in some subjective points, of the many times I've heard the Mojo I've been quite happy with how it sounds! I don't think I'd pay $500 for it, maybe closer to $300 second hand. $400 at the MOST, though I haven't sat down and did a detailed subjective review of it, I do feel having heard it now 10-11 times that it's very much on par with a lot of other competitors. The Cayin N5 ii comes to mind, as does my own Geek Out v2+ I also feel the Mojo sounds similar to how my EL Dac does,

So assuming you can pay a decent price for it, it's sonically quite competent

I'll also take this time to say I cannot STAND the Hugo 2. Horrid unit, I too had issues with RF and literally radio noise when I reviewed it. Among a myriad of other problems
 

March Audio

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Earlier I mentioned the issue the Mojo has with microphony. Here are a couple of videos demonstrating the problem. As I said, there is no point in Rob Watts talking about eliminating noise floor modulation in his conversion if the device is sensitive to vibration. As a comparison I tried the same thing with my forthcoming DAC1.

I dont think it is a major problem, well not unless its placed on your speakers, but certainly one that other DACs dont suffer from.

Note the FFT has a fair bit of averaging hence the delayed response.

Chord Mojo

March Audio DAC1
 
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derp1n

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So maybe the audible improvements Watts hears when tweaking his noise shapers from -250 dB to -300 dB are caused by the microphonics in his DAC designs reflecting the gentle thumping on the table as he tugs himself off.
 

Blumlein 88

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Earlier I mentioned the issue the Mojo has with microphony. Here are a couple of videos demonstrating the problem. As I said, there is no point in Rob Watts talking about eliminating noise floor modulation in his conversion if the device is sensitive to vibration. As a comparison I tried the same thing with my forthcoming DAC1.

I dont think it is a major problem, well not unless its placed on your speakers, but certainly one that other DACs dont suffer from.

Note the FFT has a fair bit of averaging hence the delayed response.

Chord Mojo

March Audio DAC1
Not like you are hitting it with a hammer either is it? I wonder how they do this without a tube in circuit.

Not good for any DAC, but especially for a portable one.
 

March Audio

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Not like you are hitting it with a hammer either is it? I wonder how they do this without a tube in circuit.

Not good for any DAC, but especially for a portable one.
No, gentle taps but this is still probably greater than any acoustically induced vibration you might experience from speakers in real world usage. Nonetheless it totally scuppers any claims about the benefits of eliminating conversion based noise floor modulation.
 

Thomas savage

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So maybe the audible improvements Watts hears when tweaking his noise shapers from -250 dB to -300 dB are caused by the microphonics in his DAC designs reflecting the gentle thumping on the table as he tugs himself off.
Now now :)
 

Thomas savage

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No, gentle taps but this is still probably greater than any acoustically induced vibration you might experience from speakers in real world usage. Nonetheless it totally scuppers any claims about the benefits of eliminating conversion based noise floor modulation.
It might cause a issue if i use it as a fake microphone to singing along to the music with. Honestly it’s a joke, all that design effort and it fails in this basic area.
 

restorer-john

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Note the FFT has a fair bit of averaging hence the delayed response.
Why set the FFT depth to give that delay? True microphony is instant and you need no averaging whatsoever to see it.

How do we know it's just not the PSU supply connection making a high speed intermittent connection each time you tap it and appearing in the low end of the FFT? There's nothing above LF in that video is there?
 
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How do we know it's just not the PSU supply connection making a high speed intermittent connection each time you tap it and appearing in the low end of the FFT? There's nothing above LF in that video is there?
Agreed, since the Mojo is essentially a battery powered device, why introduce the variable of a PSU, especially one with what looks like a broken cable?
 

March Audio

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Why set the FFT depth to give that delay? True microphony is instant and you need no averaging whatsoever to see it.

How do we know it's just not the PSU supply connection making a high speed intermittent connection each time you tap it and appearing in the low end of the FFT? There's nothing above LF in that video is there?
It's just how it was set for other work. No specific reason.

No it's not a bad PSU connection, and don't forget the Mojo is battery powered. It's not the cable and I have experienced this issue with the Mojo in different set ups PSU connected or not.

Why are you expecting HF in the Fft from a low frequency thump?

From an impact type stimulus the object will vibrate at its natural frequency.

Btw part of my professional background is in in vibration measurement.
 
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