[maczrool]

 
 
 
 
fQuote:

 playing dsd from foobar as dop is a bit tricky and requires a bit of trial. but once you see white light on mojo through foobar , you know how good mojo is for dsd. I successfully sent dsd256 as dop to mojo through foobar where j river failed. imho foobar is the least intrusive and lightest player which sends the cleanest stream to mojo or any dac.

Would you mind sharing how you did this?  I just got a Mojo and it plays PCM fine but will not play my DSD files (1x DSD) with foobar.  I've followed various generic DOP guides but all I get is silence although foobar says it's playing.  No amount of trial and error has yielded anything but silence unless I convert to PCM.

 

[x RELIC x]

I don’t think the Mojo is always transparent.  Rob Watts said that different impedance load to the Mojo will change the amp sound signature, specifically in the treble region. It was a compromise he had to do when designing the Mojo. 

I found it somewhere when somebody measured the frequency response of the Mojo based on different headphone impedance and found the treble frequency response changed. 

You are correct. Here is Rob's comment on the FR:

Originally Posted by Rob Watts View Post

the OP stage is integrated with the OP filter. This means that Mojo analogue section is very simple, so giving Mojo's transparency, but the downside is a small variation in frequency response with load impedance.

Rob

Frequency response is not the same as transparency. He also says elsewhere that it's only really an issue with 8 Ohm loads and even then only -0.3 dB down at 10kHz. Nothing really dramatic there. Many people measure the Mojo conventionally and don't account for the 25ms delay so they aren't getting the proper amplitude at the proper frequency in their measurements.

Edit: By the way, many other amps change the frequency response depending on the load as well.

 

[miketlse]

  Anyway that only leaves me with my RHA t20's until I get some new cans. Now the sound I am hearing is absolutely amazing, I'm now going through my music collection listening to everything, it's like having a whole new library of music. Fantastic bit of kit, and its bloody powerful for its size.

 
Many of us have experienced the same - you will start a journey revisiting your collection, and discover so many new instruments, vocals, notes, etc that previously were obscured.
Happy listening, and remember to try some of these posted tracks, which also show the potential of the Mojo http://www.head-fi.org/t/802832/mojos-greatest-hits/105

 

[Dopaminer]

....

To my ears when listening to the Mojo, or the DAVE, I hear more variety in each track, more nuance in the music, more depth. . . . 

 
For me, that is the goal right there: nuance. 

 

[musickid]

if connected via optical through my imac does the mojo treat the incoming audio signal with the same integrity as if the signal was routed through the asynchrous usb input.ie clocking? people are saying better sound through optical but I feel it is important to understand this point. only 7 days left!!!

 

[xtr4]

Just to chime in a little with regards to the "lack" of bass from the Mojo.
To me, its not really a "lack" but more of a refinement of the bass in terms of quality AND quantity. Yes, it may sound "weak" or not as thumpy as you're used to, however once you've accustomed yourself to the details the bass gives, you'll appreciate it more and find that what you're used to listening before seems bloated and somewhat "muddy" (my terminology in this respect is rather poor).
At least this is what I'm hearing. YMMV of course.

 

[Takeanidea]

  Any of you guys tried using an external amp and notice any benefits?  I would expect using the Mojo directly would sound best as there is few parts between the DAC and headphone out, but that does not seem to be the case.

I use the Mojo hooked up to my First Watt F6 Power Amp when I'm at home. I run my AKG K1000 , HiFiMan HE-6 and Sennheiser HD800 Headphones through it. @dill3000  created a mini beast of beauty when he made this for me and he has modded it to colour the sound to a warmer less clinical sound. Do I care that it is not transparent? Nope

 

[Takeanidea]

  if connected via optical through my imac does the mojo treat the incoming audio signal with the same integrity as if the signal was routed through the asynchrous usb input.ie clocking? people are saying better sound through optical but I feel it is important to understand this point. only 7 days left!!!

It'll be through a different cable . Optical also has a threshold set at 192. It won't play DSD or 32 bit etc. But optical doesn't get interference from other USB devices. The timing and any other thing you can possibly think of may well have an effect on paper. Whether you can hear that effect is the real question here. That question is easy to answer

 

[x RELIC x]

if connected via optical through my imac does the mojo treat the incoming audio signal with the same integrity as if the signal was routed through the asynchrous usb input.ie clocking? people are saying better sound through optical but I feel it is important to understand this point. only 7 days left!!!

The details about jitter can be found in the third post of this thread.

TL;DR

Chord DACs are pretty much immune to jitter on all inputs (very tiny differences) and optical will be isolated from any electrical noise from your computer by way of using pulses of light rather than a voltage down a wire for the signal.

From the third post:

But with all of my DAC's you do not need to worry at all about source jitter, so all of the above AK numbers are fine. So long as its below 2uS (that is 2,000,000 pS) you are OK, and nobody has jitter that bad!

Rob

Originally Posted by Rob Watts View Post

The reasons why sources and digital interconnects sound different are well understood - see some of my posts. In a nutshell it is not jitter (all my DACs are completely immune to source jitter) but down to RF noise and distorted currents from the source flowing into the DAC's ground plane. The RF noise inter-modulates with the analogue electronics, creating random noise as a by product, which creates noise floor modulation, and that makes it sound brighter or harder. The correlated or distorted currents very subtly add or subtract to small signals, thus changing the fundamental linearity, which in turn mucks up depth perception.

But I also agree in that lots of people hear changes that are not there - I for one have never heard any difference with optical cables (assuming all are bit perfect) with my DAC's, but lots of folks claim big differences. Placebo, or listening with your wallet, plays a part here. Then there are cases of people preferring more distortion... Listening tests must be done in a very controlled and careful fashion, particularly if you are trying to design and develop things.

Rob

Originally Posted by Rob Watts View Post

There are two problems that USB has against toslink - and one benefit. The benefit is that timing comes from Mojo - but with toslink the incoming data has to be re-timed via the digital phase lock loop (DPLL) and this is not quite as good - but you will only hear the difference via a careful AB test, so it's in practice insignificant.

The downside with USB is the common ground connection. This will mean RF noise will get into Mojo, making noise floor modulation worse. Now I go to very careful lengths to remove this problem by using lots of RF filtering, and double ground planes on the PCB, but even minute amounts of RF is significant. The other problem is down to the way that digital code works - which is in twos complement. So zero is in 24 bits binary is 0000_0000_0000_0000_0000_0000. If the signal goes slightly positive then we get just one bit changing to: 0000_0000_0000_0000_0000_0001. But if it goes 1 bit negative all the bits change to: 1111_1111_1111_1111_1111_1111. Now the problem with this is that when a bit changes, more power is needed, and this injects current into the ground of the PC - and the ground will get noisier. Unfortunately the noise is worst for small signals. Now the problem with this is that it then couples through to Mojo's ground plane, and the distorted signal currents will add or subtract to small signals - thus changing the small signal linearity. This in turn degrades the ability of the brain to re-create depth information, and so we hear it in terms of depth being flattened. What is really weird about depth perception is that there seems to be no limit to how accurate it needs to be, so the smallest error is significant.

So with toslink we do not get these problems as there is no common ground - so no RF noise, no distorted signals on the ground, and it will sound smoother with better depth against a noisy PC. But the problem can be almost eliminated by using a power efficient USB source that is battery powered - such as a mobile phone. But with noisy PC's the only way of solving it is to use galvanic isolation on the USB - but this draws power from the source, and we can't do that with mobile devices. All of Chord's desktop DAC's have galvanic isolation on the USB, and then you can't hear whether its a noisy PC or a mobile phone. In this case, USB sounds slightly better than optical, because we have the (tiny) timing benefits of USB.

I hope that explains - its a complex subject.

Rob

 

[Mython]

  if connected via optical through my imac does the mojo treat the incoming audio signal with the same integrity as if the signal was routed through the asynchrous usb input.ie clocking? people are saying better sound through optical but I feel it is important to understand this point. only 7 days left!!!

 
Please read the section entitled  'Detailed & in-depth Information on Mojo, by Rob Watts (Mojos designer)', in post #3

 

[esm87]

Just to chime in a little with regards to the "lack" of bass from the Mojo.
To me, its not really a "lack" but more of a refinement of the bass in terms of quality AND quantity. Yes, it may sound "weak" or not as thumpy as you're used to, however once you've accustomed yourself to the details the bass gives, you'll appreciate it more and find that what you're used to listening before seems bloated and somewhat "muddy" (my terminology in this respect is rather poor).
At least this is what I'm hearing. YMMV of course.

I think it would come to genre's in which the dampening of the bass feeling is tolerable. I listen to alot of hip hop etc and honestly, the 'refinement' of bass just takes it away from the music. For that genre of music, alot of tracks are about feeling the aggression in the vocals and thump/explosion in the bass. Mojo sounds great overall, this particular type of genre it takes away instead of enhances for me personally. My cayin c5 and sabre hifimediy android dac does this particular genre in general better. It brings back that feeling of oh s**t that goes hard, whilst maintaining a good quality listening experience overall. Mojo comes in too soft for me personally. You can EQ but then you take away from the bit perfect playback of the DAC (if I understand correct). It doesn't sound bad at all and may very well suit most people, just not me that is all.

Maybe hip hop music wasn't intended to be heard with such a visceral impact, and we are accustomed to exaggerated colouration etc im not sure. Thing is, if that is what your used to, anything else won't sound quite right, especially if the aggressiveness/impact sounds smoothed out. Im still fairly young (29) maybe in time I will appreciate smooth and laidback. In this particular time of my life for my music, I want vibrant, thumping, explosive, powerful, energetic. I still highly enjoy mojo for various other genre's though. It's a great sounding multifunctioning piece of kit.

 

[musickid]

​with a device like the intona high speed usb 2.0 high speed  galvanic isolator the power drain from my imac has no impact on anything. I will use the mojo in desktop mode only. is this the ideal solution or should I just go with a jitterbug or optical then? if the difference in timing is so small between optical to usb is optical the best fix then? apologies for the erratic writing as I type robotic style with my hand on my hot chocolate

 

[MartynB85]

 
It'll be through a different cable . Optical also has a threshold set at 192. It won't play DSD or 32 bit etc. But optical doesn't get interference from other USB devices. The timing and any other thing you can possibly think of may well have an effect on paper. Whether you can hear that effect is the real question here. That question is easy to answer

Optical will play DSD64 (DoP), I know because it took me a few minutes to get it going earlier. I couldn't tell the difference though going from USB DSD256 to optical DSD64. I only had some sample tracks that came with the Mojo but I have never heard anything like it, close your eyes and you are in the studio, you hear everything. I'm sticking to optical to avoid the USB issues I heard about.
 
@Maczrool Try WASAPI, it worked straight away for USB, well for me anyway.
 
I had to use WASAPI for DSD over optical. Set this as your output device. Then I had to turn on 'Use DSD Recorder' and then set your output to match the input in the DSD Processor menu. Then under the SACD menu I had to set output mode to PCM.

 

[MartynB85]

Sorry I forgot to mention the bass issue, I am used to the RHA T20's which are quite bass heavy, can be too much at times. I get that the sound may change according to headphone impedance, but they had literally zero bass. I played some tracks with heavy beats, I got nothing like what I am used to. I will try again tomorrow, the akg's have a little meat to them on my cheap soundcard but had nothing with the Mojo or my DAP, strange.
 
EDIT: I've just quickly tested them. I think I have just got used to the RHA's, I'd eq'd some bass in using my soundcard driver at some point. They sound just as tinny in the pc, but have extra top end with the Mojo. The outer layer of the pads have come off, could this cause excessive sound leakage? The mrs has commented that she can hear what i'm listening to over the tv 

 

[jmills8]

Sorry I forgot to mention the bass issue, I am used to the RHA T20's which are quite bass heavy, can be too much at times. I get that the sound may change according to headphone impedance, but they had literally zero bass. I played some tracks with heavy beats, I got nothing like what I am used to. I will try again tomorrow, the akg's have a little meat to them on my cheap soundcard but had nothing with the Mojo or my DAP, strange.

EDIT: I've just quickly tested them. I think I have just got used to the RHA's, I'd eq'd some bass in using my soundcard driver at some point. They sound just as tinny in the pc, but have extra top end with the Mojo. The outer layer of the pads have come off, could this cause excessive sound leakage? The mrs has commented that she can hear what i'm listening to over the tv 

phone, mojo, music player app, EQ the bass.