[Traveller]

...The DFR on the other hand "consumes" 40mW on average. Not that the Mojo needs much more (35mW for 600ohms, 750mW for 8 ohms), so yeah, Chord Electronics could remove the battery - or offer a "bypass" option...

I think you have not counted for the power consumption of the Mojo's own processing circuitry as we've said Mojo has many times ( hundreds of times) the processing power of other Dacs. There is a cost in power usage for that processing so it would not be possible to remove the battery and still retain a comparable performance to that we currently enjoy.

John, thank you for you feedback, sir! Of course it is understood that the Mojo does a lot more number-crunching than an off-the-shelf DAC. The values I listed above are thus just what Mojo can deliver to the headphone jack(s).
Having said that... and taking into account the original poster's goal (to enjoy the Mojo without Mojo or laptop being plugged into the mains) I suggested that based on Mojo's trickle-charge consumption (once the battery is more or less fully charged) would most likely not demand the entire ~1Amp, normally consumed when charging an empty battery.
 
But the best bet is to put it all to the test. Unfortunately it's 2 A.M. here and I can't do a full test (say, 3hrs of listening), but I can at least see what Mojo is initially requesting current-wise, while in use. So I hooked up both USB ports to my laptop (power and audio), cranked up the Mojo and Foobar and I am playing music at a normal listening level, feeding my 100ohm Etymotic ER-4S. Here is the approx. constant consumption rate:
 

 
It is entirely possible this value will increase as time goes by but 30mins into the session and I still read the same 0.12Amps

 
@Rob Watts, you're up to bat...

 

[howdy]

Was there any schematics for the Mojo "extenders"? I briefly looked.

 

[Deftone]

Where did you buy this docking station for Mojo? Any link would help.

 
he explains in his post that he made it lol

 

[Arpiben]

The mojo has the two USB sockets:

1. One socket is used for charging using the 5V connector in the USB plug
2. the other socket is used solely for the music data signal, and the 5V connector is not used. This has the key benefit of separating the potential power supply 'noise' from the music data signal.

The AQ on the other hand, uses the same USB socket to carry both the music data signal, and the 5V power supply. Consequently there is a risk of the music data signal, becoming contaminated with power supply 'noise'.

You pays your money, and you makes your choice which of the two options that you prefer.

Hi miketlse & Traveller
For sake of accuracy I would like to add that despite the fact that USB Audio port is not used for charging there is indeed +5V reaching its port due to USB protocol. Therefore Audio is not completely isolated from +5V...
Cheers.

 

[fiaharde]

Hi everyone! I'm new here and was not able to read all 1428 pages. So, I apologies if my question was answered already many times, but I could not find what I'm looking for. 
 
I have Fostex TH900 mk2 earphones which I currently use with Macbook pro (Audirvana plus) and Fiio E17 Alpen. I'm now looking to upgrade my DAC/Amp and was thinking about Oppo HA1 or Fostex HP-A8, when I came across this liitle Mojo. 
So, my question  - How good is Mojo with TH900 and how good or bad it comparing to above mentioned HA1 and A8. I'm not going to use it as a portable amp, I only need this for my Mac sitting at my home on sofa. 

 

[SearchOfSub]

Hi everyone! I'm new here and was not able to read all 1428 pages. So, I apologies if my question was answered already many times, but I could not find what I'm looking for. 

I have Fostex TH900 mk2 earphones which I currently use with Macbook pro (Audirvana plus) and Fiio E17 Alpen. I'm now looking to upgrade my DAC/Amp and was thinking about Oppo HA1 or Fostex HP-A8, when I came across this liitle Mojo. 
So, my question  - How good is Mojo with TH900 and how good or bad it comparing to above mentioned HA1 and A8. I'm not going to use it as a portable amp, I only need this for my Mac sitting at my home on sofa. 

Edit: nevermind.

 

[audi0nick128]

Hi miketlse & Traveller
For sake of accuracy I would like to add that despite the fact that USB Audio port is not used for charging there is indeed +5V reaching its port due to USB protocol. Therefore Audio is not completely isolated from +5V...
Cheers.

Hey Arpiben
Does that mean that Mojo needs the 5v connection to make a handshake for data transfer?
Was thinking about a USB cable with separate power line, that can also be unplugged... Does this make sense at all?

CHEERS

 

[Arpiben]

Hey Arpiben
Does that mean that Mojo needs the 5v connection to make a handshake for data transfer?
Was thinking about a USB cable with separate power line, that can also be unplugged... Does this make sense at all?

CHEERS

 
In order to USB's enumeration process initiates you need the +5V; once done you can remove the +5V.
It may make sense to have a DIY USB cable with separate power line provided that Mojo is working on battery.
I didn't try it myself yet (sacrifice an old cable) in order to know if it will bring any significative SQ improvement.
Cheers.

 

[audi0nick128]

In order to USB's enumeration process initiates you need the +5V; once done you can remove the +5V.
It may make sense to have a DIY USB cable with separate power line provided that Mojo is working on battery.
I didn't try it myself yet (sacrifice an old cable) in order to know if it will bring any significative SQ improvement.
Cheers.

Thanks for the clarification... Might try this soon, will report back.
Cheers

 

[Traveller]

 

But the best bet is to put it all to the test. Unfortunately it's 2 A.M. here and I can't do a full test (say, 3hrs of listening), but I can at least see what Mojo is initially requesting current-wise, while in use. So I hooked up both USB ports to my laptop (power and audio), cranked up the Mojo and Foobar and I am playing music at a normal listening level, feeding my 100ohm Etymotic ER-4S. Here is the approx. constant consumption rate:

It is entirely possible this value will increase as time goes by but 30mins into the session and I still read the same 0.12Amps

 
 
...change of plans 

- I simply left the Mojo / Foobar running all night and ~7hrs later we have the same values

 
I recorded +14°C over ambient after 1hr as well as after the 7hrs, so temps are constant. Once I turned it off & unplugged it completely (and gave it a 5min "rest"), I switched it back on and was pleased to see that the Pwr LED was blue...

 
So here's the real difference, @brent75  between Mojo and DRF:

 
And I'm sure someone with a bit of EE background ( @Arpiben ) can clarify the consumption impact on a typical laptop battery for EE-impaired guys like me

but even I can determine a few things:
1. Mojo draws 0.12A while the DRF is more economical at 0.04A.
2. Running Mojo for 7hrs cost my laptop ~ 800mAh / 4Wh...
 
Well, it looks to me like even Mojo is economical enough (... me thinks 

).  my HP Spectre x360 comes with a "56 WHr" (~ 5000mAh?) battery and I can get ~5hrs+ out of it. That's w/o the Mojo charging off of it. So I'm not sure we're allowed to apply simple math to power usage but IFF... 56Whr - 4WHr = 52WHr left for my other laptop duties, so I think I could live with that as it should still come close to the 5hrs.

 
~~~~
 

For sake of accuracy I would like to add that despite the fact that USB Audio port is not used for charging there is indeed +5V reaching its port due to USB protocol. Therefore Audio is not completely isolated from +5V...

In order to USB's enumeration process initiates you need the +5V; once done you can remove the +5V...

 
Alors, c'est très intéressant... but also unfortunate for us (audiophiles) as we could do without it...

 

 

[gikigill]

Joining the Mojo team, looking forward to my first FPGA based dac after a Femto DS and R2R.

 

[Rob Watts]

Mojo needs the +5v on the USB VBUS wire permanently; I use this wire simply to tell the FPGA to select the USB as an input, then to shut down power to the OPT receiver and coax SPDIF interface chip.
 
The wire is just used to sense, and is very heavily filtered; there is no way RF noise from this line can affect Mojo, so don't worry about it.
 
Rob

 

[audi0nick128]

Mojo needs the +5v on the USB VBUS wire permanently; I use this wire simply to tell the FPGA to select the USB as an input, then to shut down power to the OPT receiver and coax SPDIF interface chip.

The wire is just used to sense, and is very heavily filtered; there is no way RF noise from this line can affect Mojo, so don't worry about it.

Rob

Thanks for clarifying the clarification

CHEERS

 

[Traveller]

  Mojo needs the +5v on the USB VBUS wire permanently; I use this wire simply to tell the FPGA to select the USB as an input, then to shut down power to the OPT receiver and coax SPDIF interface chip.
 
The wire is just used to sense, and is very heavily filtered; there is no way RF noise from this line can affect Mojo, so don't worry about it.
 
Rob

@gikigill that's the kind of feedbck / transparency you can expect here from the lads at Chord

Welcome aboard, M8!

 

[jmills8]

@gikigill
that's the kind of feedbck / transparency you can expect here from the lads at Chord


Welcome aboard, M8!

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