Chord Mojo DAC-amp ☆★►FAQ in 3rd post!◄★☆
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JaZZ

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  There is no amp section. The DAC drives the HP.
 
That's not entirely correct. The line-out stage is an amp. The Mojo just renounces an additional headphone amp.
 
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That's not entirely correct. The line-out stage is an amp. The Mojo just renounces an additional headphone amp.

Isn't the only thing between the DAC output and the 3.5mm connector an I-to-V converter?

This is not an amp.
 
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  There is no amp section. The DAC drives the HP.
  That's not entirely correct. The line-out stage is an amp. The Mojo just renounces an additional headphone amp.
Isn't the only thing between the DAC output and the 3.5mm connector an I-to-V converter?

This is not an amp.
 
To be more specific, the headphone outputs are driven by the analog output stage of the DAC, which does have "a very high performance op-amp with a discrete op-stage as a hybrid with a single global feedback path." (Nearly every other DAC has an op-amp or something similar too to amplify the signal before sending it to an external amp.) I think most who are interested in Chord DACs are already aware that there is no separate amp section.
 
More info here: http://www.head-fi.org/t/702787/chord-hugo/1830#post_10459450
 
Clarification: the Mojo uses parallel transistors.
 
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JaZZ

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The DAC output (stage) is an amp.
 
Music Alchemist beat me to it. – Note that «op amp» in this case means «output amp», not «operational amplifier».
 
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To be more specific, the headphone outputs are driven by the analog output stage of the DAC, which does have "a very high performance op-amp with a discrete op-stage as a hybrid with a single global feedback path." (Nearly every other DAC has an op-amp too to amplify the signal before sending it to an external amp.) I think most who are interested in Chord DACs are already aware that there is no separate amp section.

More info here: http://www.head-fi.org/t/702787/chord-hugo/1830#post_10459450

Is mojo the same as hugo? The block diagrams I saw suggest otherwise.
 
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The DAC output (stage) is an amp.

Music Alchemist beat me to it. – Note that «op amp» in this case means «output amp», not «operational amplifier».

And what is an "output amp" designed with if not an op amp??
 
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Is mojo the same as hugo? The block diagrams I saw suggest otherwise.
 
If by "the same" you mean that there is no separate amp section, then yes. But there are obviously many other differences.
 
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If by "the same" you mean that there is no separate amp section, then yes. But there are obviously many other differences.

By the same I mean there is an op amp in the Mojo analog path. I've been lead numerous times to believe this is not the case with Mojo... so please, could you post the diagram or source that suggests there is an op amp in the Mojo?
 
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By the same I mean there is an op amp in the Mojo analog path. I've been lead numerous times to believe this is not the case with Mojo... so please, could you post the diagram or source that suggests there is an op amp in the Mojo?

I, too, have been led to believe from John and Rob's comments there is no op amp in the analog path.
 
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I, too, have been led to believe from John and Rob's comments there is no op amp in the analog path.
 
Isn't it discrete output stage (JFET, etc.) and not op amp?
 
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By the same I mean there is an op amp in the Mojo analog path. I've been lead numerous times to believe this is not the case with Mojo... so please, could you post the diagram or source that suggests there is an op amp in the Mojo?
  I, too, have been led to believe from John and Rob's comments there is no op amp in the analog path.
  Isn't it discrete output stage (JFET, etc.) and not op amp?
 
From here:
 
Q: Is the Mojo analogue section Class A like the Hugo?
A: “The actual OP stage is identical - same OP transistor silicon - but I used 6 small transistors in parallel rather than 3 large devices. It’s biased at the same Class A level."
 

 
Some other relevant info:
 
http://www.head-fi.org/t/702787/chord-hugo/10320#post_11527678
 
  What is an OP stage?
OP is output, and it replaces rather poor OP stages within op-amps. When faced with designing the electronics of Hugo, I had no experience of designing headphone amps - looking into devices that supplied headphones, they were very poor. So I designed it as if it was a power amp (I've designed lots of those) and gave Hugo the ability to drive 8 ohm loudspeakers directly - which means lots of current - in Hugo's case I set it too 0.5A RMS. You will not get this current from op-amps or headphone drive chips, so I had to design a discrete amp. Now to get the best transparency there needs to be a single feedback path, so the discrete OP stage needs to be within the op-amp's global feedback path. Since the op-amps are very high gain bandwidth product devices (high speed), that meant designing a Class A OP stage with very low propagation delay, so that the circuit would remain stable. Now the op-stages in op-amps are pretty poor to awful, so when I got the first prototype I was very pleased at how good the OP stage sounded, and how much lower distortion was (particularly high order harmonics) - even when using the op-stage in DAC mode with easy loads. Indeed, I now use this arrangement all the time now, as it really improves the performance of the op-amp - that's why 2 Qute has it too. The OP stage is by far the weakest part of all op-amps and this is simply because one can use a decent Class A bias current, and very substantial OP transistors, so thermal stability is ensured. And yes, Hugo does not have an analogue volume control, so this means the analogue section is very simple (just 2 resistors and capacitors in the direct signal path). Simple analogue gives much more transparency.
 
https://en.wikipedia.org/wiki/Operational_amplifier
 
An operational amplifier (often op-amp or opamp) is a DC-coupled high-gain electronic voltage amplifier with a differential input and, usually, a single-ended output.
 
http://electronics.stackexchange.com/questions/94344/opamp-vs-transistor
 
An operational amplifier is the equivalent of many transistors and is thus able to perform much better than a single transistor (e.g. higher input impedance, lower output impedance, higher gain, differential inputs and/or differential outputs, etc.).
 
It would appear that op-amps and transistors can in some cases be synonymous.
 
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  O.K. I will take that advice. Can you suggest a good Toslink cable that is very short and not very expensive?
I'm not sure if you have found your solution yet, but the Chord Mojo accessory kit contains OTG, Toslink etc and at a reasonable price too (less than it cost me to get my SySconcept cable delivered to the UK.

May not be the ideal solution but one that is readily available.
 
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I have also been unable to fix its "mechanical" sound signature no matter how I equalize it. It's probably just a property of the drivers. The detail and imaging are insanely good, but it doesn't seem to be able to reach the level of neutrality, transparency and naturalness as the STAX SR-207. (Which I never felt the urge to equalize.)
 
imo the most enjoyable headphones to use are the ones that dont need any mods or EQ, the rabbit hole can seem endless.
 
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Black or silver? That is the question.
 
So how many of you fellow Mojo'ers are thinkin' of adding the Hugo 2 to your systems?
 
I think the ultimate compliment to the Mojo is that listening to it is such a revelation that it tempts me to upgrade to a higher-end Chord DAC sooner than planned.
 
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Black or silver? That is the question.

So how many of you fellow Mojo'ers are thinkin' of adding the Hugo 2 to your systems?

I think the ultimate compliment to the Mojo is that listening to it is such a revelation that it tempts me to upgrade to a higher-end Chord DAC sooner than planned.
Im thinking of getting one but the Hugo 1 is what im looking at and black.
 
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