CHORD Mojo 2 Review (Portable DAC & HP Amp)

[Ken Tajalli]

There is no need to have a high idle current.

As I said, I don't believe he did - he did where it was feasible (at lower powers).
He got 8+ hours from a 1650mAh battery on USB, about 10-15% longer on Toslink.
Hugo2 does 6+ hours with much larger batteries.

 

[solderdude]

As I said, I don't believe he did

Then it wasn't class-A for high impedance headphones, at the most partial class-A in high impedance headphones which technically all class-AB output stages are.
Chord doesn't mention class-A either but it could be an A-class amplifier where A-class could be 'top notch'...

 

[Ken Tajalli]

...... at the most partial class-A in high impedance .....

All class AB's are partial class A at lower outputs- No?

Chord doesn't mention class-A either but it could be an A-class amplifier where A-class could be 'top notch'...

RW has mentioned it many times is that unscientific sister forum!
Chord couldn't say, under some circumstances it is A otherwise it isn't! Could they - hence luring in class A believers was not a marketing ploy.

 

[lewdish]

For the price you expect a lot more power output~ some dongles are putting out more power than this nowadays even. The irony is that they claim "Supports 800Ω Headphones" which seems pretty doubtful given the output on 600Ω load. Glad to see that it's made some improvements, but the USB-C Implementation is abysmal and extremely crude as it requires you to run a separate input for data and power (via micro-usb 2022...). DSP Functions also seem pretty crude and limited in terms of what kinds of filters you can apply, they really should have developed a better implementation... I guess we're off to wait a few more years for a true mojo re-work.

 

[solderdude]

All class AB's are partial class A at lower outputs- No?

At low output currents yes but then its called a class AB not a class A.
When RW states it is class-A for high impedance headphones then it can't be partial class-A for high impedance headphones it must have an idle current higher than the current draw at max output voltage by definition.

The real question is what RW considers high impedance and if by class-A he means real class-A and not partial or up to a certain output level.
I mean.. is 120ohm high ? 250ohm, 300ohm, 600ohm or 2kohm ?

RW has been known to make some statements that were... lets say... suspect before.

Measure and thou' will know.

 

[kanefsky]

This may be true for later model iPads (we are starting to agree here which makes me happy!), but even with powered DAC/amps, I have a couple of portables that require me to use the kit I posted and have it connected to power for them to work on my second gen iPad Pro. I get a compatibility error (even with the latest firmware), and the iPad refuses to switch the audio output to the external DAC without it. I cannot explain why, and these are also four or five year old DAC/amps. I’m guessing newer DACs are starting to use more compatible USB ports themselves, similar to the inclusion of lightning OTG cables that obviate the use of the older iPhone CCKs. All of the portables I’ve purchased in the last couple of years (both from iFi and FiiO) come with lightning and USB C OTG cables that circumvent the use of any other adapters.

The only reason I raised any concern to the OP is that I don’t know what generation iPad he has, and since I don’t own any Chord products I don’t know how proactive they are with Apple compatibility. But as you said, the Mojo 2 is working for you, so I edited my original post to correct that yesterday.

You're talking about the Digital AV adapter, which is not the camera connection kit (which is only available for Lightning). I believe in this case it's just acting like a powered USB hub and there's no fundamental USB compatibility issue like there is with trying to convert Lightning to USB. Do any of the DACs you're had problems with have dedicated power ports so that they're not depending on drawing power over the USB data connection?

I just tested my 7-year-old Sony PHA-3 DAC (which has a power input and a battery just like the Mojo 2) and it connected to my iPad just fine using a random USB-C to Micro USB cable, and also using a random USB-A to Micro USB cable with a random USB-A to USB-C adapter plug.

 

[dc655321]

If you insist on that sort of "science" overhead to support every single comment

I don't insist, but for statements unsupported by evidence.
That a really poor strawman argument, commonly produced when people try to deflect from their own BS.

Amir's work showed there are certainly enough measurable improvements in the product to support a claim of audible improvements

No, they really don't (OG measurements).

you should ignore me and move on.

Done.

 

[Ken Tajalli]

Measure and though will know.

You mean thou'

 

[AudioSceptic]

There's a USB-C to USB adaptor from Apple, but its not a CCK. The latter was only required to connect to LIghtning ports (which do some auto-routing of their connections depending what you are running to/from the device).

I promise—I am not the kind of person to keep doubling down if I’m mistaken. This is the equivalent of the Lightning CCK for the iPad. Like the iPhone version, it has come in two hardware versions, and the earlier models are no longer compatible with later model iPhones and iPads. This AV adapter is required for earlier generation iPads and iPad pros with USB-C ports to provide adequate power for power hungry devices attached, and they also allow bypass of the internal DAC on early iPad models plus compatibility for DACs that use USB A connectors.

There are also firmware updates for these devices that are automatically updated upon connection, and unlike other iOS peripherals, you get a popup window for the upgrade process as its installing.

Again, the most recent model iPad Pros have a much more powerful USB bus, and I don’t own one. But for my 2019-2020 model, at least two of my portable DACs will not work without this adapter.

If they allow bypass of the internal DAC, that suggests you would otherwise get an analogue output. How would there be analogue in a Lightning or USB-C port (the earlier 30-pin connector did have an analogue output for use in docks, I believe)? Or do you just mean that the headphone output is muted?

 

[srkbear]

You're talking about the Digital AV adapter, which is not the camera connection kit (which is only available for Lightning). I believe in this case it's just acting like a powered USB hub and there's no fundamental USB compatibility issue like there is with trying to convert Lightning to USB. Do any of the DACs you're had problems with have dedicated power ports so that they're not depending on drawing power over the USB data connection?

I just tested my 7-year-old Sony PHA-3 DAC (which has a power input and a battery just like the Mojo 2) and it connected to my iPad just fine using a random USB-C to Micro USB cable, and also using a random USB-A to Micro USB cable with a random USB-A to USB-C adapter plug.

OK I am raising the white flag <g>. All I care about is whether the OP got the right answer to his question, and it appears that with the help of others that were not me, he did.

 

[kanefsky]

For the price you expect a lot more power output~ some dongles are putting out more power than this nowadays even. The irony is that they claim "Supports 800Ω Headphones" which seems pretty doubtful given the output on 600Ω load. Glad to see that it's made some improvements, but the USB-C Implementation is abysmal and extremely crude as it requires you to run a separate input for data and power (via micro-usb 2022...). DSP Functions also seem pretty crude and limited in terms of what kinds of filters you can apply, they really should have developed a better implementation... I guess we're off to wait a few more years for a true mojo re-work.

I agree with most of your criticisms. I wish that they'd put more attention into the USB implementation rather than only focusing on their custom DAC. The micro USB ports are there for backwards compatibility with their Poly streamer, but I'd rather they just had a separate product with both DAC and streaming rather than the concept of attaching a second device to add streaming (the Poly also appears to block all the built-in inputs when it's attached). Either way it would have been nice if the USB-C port allowed for combined power and data and if they had eliminated the white noise issue.

Parametric EQ and all that would be nice but it would either require a much more complicated interface on the device, or it would require that they add Bluetooth and design an app to control it. Either way it would kind of spoil the minimalism of the Mojo 2 which is one of the things I like the most about it.

Something else I don't think I've seen mentioned here which might bother many users is the boot time (I assume due to the custom DAC implementation rather than off-the-shelf chips). It takes about 20 seconds after turning the Mojo 2 on before it's ready to play. That's not an issue for how I'm using it but if I were using it on-the-go that would probably bother me quite a bit.

 

[srkbear]

If they allow bypass of the internal DAC, that suggests you would otherwise get an analogue output. How would there be analogue in a Lighting or USB-C port (the earlier 30-pin connector did have an analogue output for use in docks, I believe)? Or do you just mean that the headphone output is muted?

Meaning that with the device attached, the iPhone/iPad does not default to its internal DAC and uses the one attached externally. When the attached DAC fails to connect properly, the phone or tablet won’t switch to the proper audio processing device. Sorry for the confusion.

 

[AudioSceptic]

Meaning that with the device attached, the iPhone/iPad does not default to its internal DAC and uses the one attached externally. When the attached DAC fails to connect properly, the phone or tablet won’t switch to the proper audio processing device. Sorry for the confusion.

Forgive me for being dense, but what is the output of the internal DAC connected to? I thought it could only be the headphone (3.5 mm) socket. Doesn't the Lightning or USB-C port always have access to the digital output of the iPad's audio system?

 

[Garrincha]

For the price you expect a lot more power output~ some dongles are putting out more power than this nowadays even. The irony is that they claim "Supports 800Ω Headphones" which seems pretty doubtful given the output on 600Ω load. Glad to see that it's made some improvements, but the USB-C Implementation is abysmal and extremely crude as it requires you to run a separate input for data and power (via micro-usb 2022...). DSP Functions also seem pretty crude and limited in terms of what kinds of filters you can apply, they really should have developed a better implementation... I guess we're off to wait a few more years for a true mojo re-work.

I don't like this device in particular or Chord in general as well, and prefer dongles myself, but which dongle produces 70 mW at 300Ohm and 400mW at 33 Ohm?

 

[Ken Tajalli]

I don't like this device in particular or Chord in general as well, and prefer dongles myself, but which dongle produces 70 mW at 300Ohm and 400mW at 33 Ohm?

 

[srkbear]

Forgive me for being dense, but what is the output of the internal DAC connected to? I thought it could only be the headphone (3.5 mm) socket. Doesn't the Lightning or USB-C port always have access to the digital output of the iPad's audio system?

It’s connected to the device’s tiny internal amp and speakers. The lightning port is the connector now for headphones as well (for the wired options) with an adapter to 3.5mm—I’m not certain how they work exactly but I have to assume that the adapter has it’s own micro DAC and amp built in because the lightning port is a digital data connection.

 

[staticV3]

You can transmit analog audio via Lightning just like you can via Type-C.
It's all a question of configuration. The plug itself is not a problem.
It's basically just a more complicated minijack.

 

[Axo1989]

You can transmit analog audio via Lightning just like you can via Type-C.
It's all a question of configuration. The plug itself is not a problem.
It's basically just a more complicated minijack.

I'm not sure that's true re analog audio: Lightning is essentially a digital serial port. My recollection is that both the Apple Lightning to stereo 3.5 mm dongle (reviewed by ASR) and the bi-directional Lightning to/from 3.5 mm cable (introduced with the AirPods Max) are DACs (or ADC/DAC in the latter case). But I may have missed something, I don't have that developer documentation at hand.

OK I am raising the white flag <g>. All I care about is whether the OP got the right answer to his question, and it appears that with the help of others that were not me, he did.

Haha I swear I wasn't going to war, it was a special technical operation.

Fyi the CCK (camera connection kit) originally offered by Apple was a bundle with a Lightning-to-USB and a Lightning-to-SD Card adaptor included. The former is still offered separately but is called a camera adaptor. I think you've figured out that Lightning active routing issue and the USB-C power supply issue are different things, technically.

For the Mojo, Chord offered a connection kit which included a (Poly-sized) module that snapped on and housed the USB end of the Apple camera adaptor, plus some silicon bands that allowed you to strap the combination to an iPhone (I used this for a while when faced with a long commute). Mojo didn't have the Apple MFi chip built-in (and wasn't certified) so needed the camera adaptor to receive digital audio over Lightning.

Of course you don't need these shenanigans with Mojo 2 and USB-C.

 

[Garrincha]

Commenting on the pic, this is such an unconvenient, clumsy, heavy, ugly and bulky mess, I have almost no words for this (besides these).

 

[Somafunk]

Commenting on the pic, this is such an unconvenient, clumsy, heavy, ugly and bulky mess, I have almost no words for this (besides these).

You’d claw your eyes out with some of the so called “portable headphone rigs” on headfi,