[Music Alchemist]

  you are arguing semantics I never said there was an extra amplification stage, just that the output is amplified, which it is. In their own description they said they designed the output stage as a simple OPamp.
 
Whether or not there is a reason why some one would want to use it as a stand alone amp really wasn't the point. The point is its a typical limitation of this and other integrated gear.

 
Okay, but you can use it as a standalone DAC (with an external amp) with no downsides. Also, all DACs amplify their output (from a small digital signal to a stronger analog signal) if you really want to get technical about it. I believe you can still use the Mojo with most external DACs. (It has many inputs.) I know you can with various DAC/amps too. I use my DAC/amp as just an amp, since I like my laptop's onboard DAC more.

 

[fjrabon]

  We are both correct actually. It comes down to how you look at it with regard to the output stage. Yes it does line level by setting a specific level to the output. But it is still going through the amplification stage because their is no way around it. 

by this logic, literally every single DAC "goes through an amplification stage" as every DAC has to output in the analog realm, because, well, that's the entire definition of digital to analog converter.  Every single DAC ever made has some sort of "amp" in the analog output stage
 
The Mojo uses digital realm volume attenuation and actually controls volume in the digital realm before it even gets to the analog stage.  Essentially it's just like DACs that have a pre-amp knob (my iDAC6 has one).  Its analog output can either change from a headphone ready low impedance output (topping out at about 600mW @ 0.08 Ohms) to a higher imepdance line level (3v) output, dependent on the mode.  There is no "amp section" to the Mojo, there is simply the analog section of the DAC.  
 
Yes, we can argue semantics about whether this is an amp or if it's the analog section of the DAC.  But you are attempting to argue it both ways, you want to call it an amp when it's on the Mojo, but apparently don't want to call the analog stage an amp when it's on every other DAC.  A DAC chip itself can't output 1.5-3V (depending on which output standard you are talking about), it needs some sort of analog "amp" type stage.  
 
Most DACs would do what Mojo does if they could, but their architecture prevents it.  Here is Rob Watts on why he was able to do this with Mojo and why it isn't really possible with most DAC designs:

 

  1. Silicon DAC's are horribly noisy, as the substrate and grounds are bouncing around due to switching activity. So to counter this, it is done differentially, which means the ground noise is cancelled. It also hides the problems of the reference circuitry, which can't be made with low enough impedance on silicon. This translates to more distortion, and crucially noise floor modulation.
 
2. Delta sigma converters run at low rates - best is at 12 MHz - this means that there is a lot of noise that must be aggressively filtered out in the analogue section. This also applies with R2R DAC's too as these have even worse problems due to the very slow switching speed.
 
So to run with a single amp section you need the DAC to be single ended and to run the noise shapers at much higher rates to reduce your filtering requirements. Because the analogue section with Mojo is discrete, I can use extremely low impedance and low noise reference supplies - something that is impossible on silicon. This has the other benefit of eliminating noise floor modulation (actually there is a lot more to it than this as there are countless other sources of noise floor modulation in a DAC). To make the filtering easier, the pulse array noise shapers run at 104MHz - over an order of magnitude faster than normal. There are other benefits to running the noise shapers at 104MHz, principally the resolving power of the noise shaper. Now soundstage depth is determined by how accurately small signals are reproduced. The problem with noise shaping is that small signals get lost - any signal below the noise shaper noise floor is lost information. But by running the noise shaper at much faster rates you solve this problem too - indeed Mojo noise shapers exceed 200dB THD and noise digital performance - that's a thousand times more resolving power than high end DAC's.
 
If I get time today I hope to publish noise floor modulation measurements showing Mojo has zero measured noise floor modulation. This level of performance does not happen on any other non pulse array DAC's at any price, and its the primary reason why Mojo sounds so smooth and musical.
 
Rob

 
 
Edit: it is theoretically possible to design a DAC with no amp stage in it at all, but there are a ton of drawbacks to this approach, and literally no DAC maker does it this way.

 

[gabrihamlincoln]

I think my Mojo sounds much better than my Bifrost IMO. Can fit a lot more in that aluminum chassis, ya know.

 

[Snowpuppy77]

Is your Bifrost a mulibit?

 

[Naugrim]

Mine is not multibit and Mojo is much better. I'm trying to decide if I should upgrade my Bifrost to a Bimby instead of use my Mojo as a desktop DAC. 

 

[bharat2580]

  Mine is not multibit and Mojo is much better. I'm trying to decide if I should upgrade my Bifrost to a Bimby instead of use my Mojo as a desktop DAC. 

​just get a decent amp to pair with your DAC and keep mojo for the travel.

 

[Music Alchemist]

Edit: it is theoretically possible to design a DAC with no amp stage in it at all, but there are a ton of drawbacks to this approach, and literally no DAC maker does it this way.

 
Except MSB.

 

With the high-output power provided by the Hybrid DAC modules, the need for amplification is eliminated. The signal is attenuated with new technology that provides a constant low impedance output without any active circuitry (no transistors, buffers or op-amps).

 

[fjrabon]

Except MSB.

Oh, man, interesting. Was wondering when this would eventually happen. Wonder if you can use one of these to directly run to a headphone.

 

[theveterans]

  Mine is not multibit and Mojo is much better. I'm trying to decide if I should upgrade my Bifrost to a Bimby instead of use my Mojo as a desktop DAC. 

 
Just do both. I have both and Bimby >= Mojo in my ears unless you prefer the sound of Mojo over the "livelier" sound of Bimby.

 

[Music Alchemist]

Oh, man, interesting. Was wondering when this would eventually happen. Wonder if you can use one of these to directly run to a headphone.

 
Yes, some people drive headphones directly from that DAC...but the thing costs as much as a decent house.

 
In other news...I just bought a NightHawk and Mojo!

 

[Naugrim]

   
Yes, some people drive headphones directly from that DAC...but the thing costs as much as a decent house.

 
In other news...I just bought a NightHawk and Mojo!

Congrats! I'm trying to sell my NH, you could have gotten quite a deal.

 

[guitardave]

Not about the Bifrost but here is my Modi MB experience vs. Mojo:
I recently bought (after all the hype!) bought a Modi Multibit and a Jotunheim w/dac.  The Jot w/dac was fine with my Utopias and other phones.  When I added the Modi, the pleasure went up considerably.  It is much better than the Jot dac, but that is fine until you hear better!  I also have a Mojo.  
In my main system (ARC Ref6/Ref75se) I use a Metrum Hex.  I have been planning to get the Pavane, so I listed my Hex for sale, and started planning on what to use if the Hex sold and I had to use others in it's place waiting for my Pavane (haven't we all had such mental debates in this hobby?).  I tried slotting in the Modi, as I had hoped it would be close.  It was not.  The Hex KILLED it.  As it should, given the huge price difference, but time marches on, so I had hope that maybe this MB stuff would be a giant killer.  And maybe the upper level products would be, but not the Modi under the ARC microscope.  As I said, it sounded GREAT and very musical with headphones, just not in the big rig.  The shock for me, and why I responded to this thread, was how good the Mojo sounded when inserted into the system.  It sounded great.  A little less bass and meat on the bones than the Hex, but it actually seemed a bit more transparent.  I think this came down to the less meat seeming like more transparency than actuality, but it did not disappoint in any way, and I sold and shipped the Hex.  What this caused me to do, was buy a Hugo TT to try both as headphone amp and system source, based on the Mojo performance.  I held off on ordering the Pavane, until I hear the TT in the system.  The TT arrives tomorrow, and Monday I will either order a Pavane, or not. I really like the Metrum signature and appreciate its virtues, and it will be doing MQA, so I know I will be ordering one soon...  But if the TT blows me away I may wait a couple weeks until fully functional Level 2 MQA Pavanes are available.
Long story short, the Modi MB is a very nice dac in a headphone system, but ultimately I found the Mojo much better, at about twice the price...  On the other hand, the Mojo needs no amp.

 

[Music Alchemist]

  Well, since it just uses the DAC's analog output (without any extra amplification stage existing in the first place; its amplification works by reducing the level of that output, not adding something that wasn't already there), the line out is practically the same as any other, aside from the fact that you can't bypass the DAC, which is always in use. Plenty of people use Chord DACs (including the Mojo) as standalone DACs. But I don't see why anyone would want to use it as a standalone amp with another DAC.

 
I would like to make a few corrections here, especially after having owned the Mojo for some months.
 
It does not reduce the level of the output, and it does have amplification in the form of parallel transistors in the DAC's analog output stage.
 
Technical details here:
http://www.head-fi.org/t/784602/chord-mojo-dac-amp-faq-in-3rd-post/29670#post_13206949
 
You also cannot use it as an amp with another DAC, as it only has digital inputs.

 

[theveterans]

   
I would like to make a few corrections here, especially after having owned the Mojo for some months.
 
It does not reduce the level of the output, and it does have amplification in the form of parallel transistors in the DAC's analog output stage.
 
Technical details here:
http://www.head-fi.org/t/784602/chord-mojo-dac-amp-faq-in-3rd-post/29670#post_13206949
 
You also cannot use it as an amp with another DAC, as it only has digital inputs.

 
The analog stage is tied to FPGA so there's no way to use it as amp

 

[Music Alchemist]

  The analog stage is tied to FPGA so there's no way to use it as amp

 
That's pretty much what I said.