[Mython]

Going to buy a Schiit Valhalla 2 amp, using my mojo as dac into that would be double amping right?

No, that would not be 'double-amping', as such.

Because Rob's DAC topology is unique, Mojo does not incorporate an 'amp stage', in the conventional sense.

I've extensively quoted Rob's discussion on this topic ('about Mojos output stage'), in post #3 of this thread, so I urge you to read this - it's very informative.

Post #3 also contains the following useful section:

Spoiler: Detailed & in-depth Information on Mojo, by Rob Watts (Mojos designer) > Spoiler: Informative posts by Rob Watts


Unfortunately, when the forum software was changed, a few months ago, the new software utterly butchered the formatting of post #3, detrimentally affecting not just the clarity of the layout and navigation but also stupidly truncating nested quotes to the point where they are almost unreadable. Just know that if you encounter a nested quote that includes Rob, then it has been included for good reason, even if the text has been severely truncated, in which instances, you can click on the tiny arrow next to the commentator's name, which will take you to their original full post within the thread.

 

[pete321]

thanks, I will check it out, i read a post online after I posted about someone with my same setup I had in mind and he was happy, and how it's not double amping, good to know.

 

[Leo-]

Looking for a small and (preferably) cheap transport for the Mojo for DSD. I would like to confirm if the Cayin N3, Shanling M2S and Hizs AP60 are all capable of bit perfect DSD.

N3 does DXD but is a bit less stackable, M2S does DSD256 and AP60 is the cheapest. Any other recommendations?

I didn't succeed in outputing DSD from my Android phone (always show purple not white). Works fine from my other sources though.

 

[Hooster]

thanks, I will check it out, i read online after I posted about a person with my same setup I had in mind and he was happy, and how it's not double amping, good to know.

It is in fact double amping, since the Mojo does in practice work as a headphone amplifier. Further amping is not needed. The only reason to amp a mojo is to introduce a distortion/flavour that pleases you. If you are sure you really want the flavour that the extra amp introduces it might be worth buying. If not, save your money or spend it on something that actually does something useful.

 

[Mython]

It is in fact double amping, since the Mojo does in practice work as a headphone amplifier. Further amping is not needed. The only reason to amp a mojo is to introduce a distortion/flavour that pleases you. If you are sure you really want the flavour that the extra amp introduces it might be worth buying. If not, save your money or spend it on something that actually does something useful.

You're not new around here, so I'm sure you know that it's a tricky question and one that has been discussed endlessly in this thread, over the past couple of years.

I'm not saying you are 'wrong', and I actually agree that adding an amp will introduce a certain "distortion/flavour" to the sound, which isn't strictly necessary.

My intention was simply to draw attention to the fact that Mojo does not have a complex discrete amplifier circuit in the conventional sense, and that Mojos output transistors can be set to a line-level where they can satisfactorily feed a seperate amplifier. I gave a brief answer and perhaps I should have elaborated, but that was why I pointed to existing discussion on the matter.

It might be inconvenient to some who prefer to think in entirely conventional terms, but it's an important distinction.

Cheers.

 

[Leo-]

Well said Mython. In my experience with the iMod (which also doesn't have an amp in the output circuit), the line out is quite edgy and it is hugely beneficial to add an amp at the output. The output of the Mojo is smoother, therefore an amp is not really needed. The main reason for doing this would be if an analog volume control would work better than the digital control in the Mojo. I haven't tried yet myself.

 

[jdpark]

I use the line out of the Mojo a lot, into two different amps (in two offices) and to my main system. Actually, I use the line out function more often than the regular headphone jack.

One thing I've found which is quite strange is that when I'm listening to 44.1/16 (i.e. Redbook) wav/flac/alac files I hear an improvement in quality of the tone and timbres of instruments over my HRT HD, which came out several years ago. However, in every 24-bit setting (88/96/176/192Hz), the HRT HD really kills the Mojo. It is more dynamic, punchy, and the soundstage is better. Also, I've been experimenting with DSD and I can't tell that the Mojo makes DSD (64/128/256) sound much better than 44.1/16 (maybe a bit, but not night and day). In fact, the DSD performance was so poor, I downloaded Jriver to convert to PCM on the fly and noticed that the HRT HD sounded better in 176/24 than the native DSD does on the Mojo. I also get annoying digital pops when I play 256DSD from my computer.

Is it possible that the Mojo wasn't meant to be used with a computer, or alternatively that it wasn't meant to be used with an amp at all?

In my view the Mojo isn't a real hi-rez dac. Just because it can technically decode the stuff, doesn't mean it does it well at all, or that you will actually hear an improvement. But on the upside, it's a fantastic Redbook machine, especially if you like mid-centered music rolled off highs.

 

[SilverEars]

I'm feeding it to my JBL 305 powered monitors. It's a clean source.

 

[musickid]

mojo has a beast of an amp. save your money for high end headphones. that will give you a 'new' sound imho.

 

[Music Alchemist]

Going to buy a Schiit Valhalla 2 amp, using my mojo as dac into that would be double amping right?

Would using a modi 2 dac to valhalla 2 sound better than using the mojo setup for hd650? Can't afford anything else than that for a dac at the moment.

It is in fact double amping, since the Mojo does in practice work as a headphone amplifier. Further amping is not needed. The only reason to amp a mojo is to introduce a distortion/flavour that pleases you. If you are sure you really want the flavour that the extra amp introduces it might be worth buying. If not, save your money or spend it on something that actually does something useful.

All DACs have amplification of some sort; Chord adapted their DAC/amps to be able to drive headphones directly from the analog output. (There are six parallel transistors there in the Mojo's case.) Many sources indicate that it's actually cleaner than the line outs of most DACs. My perspective is that if you want to call it double amping, you might as well say connecting any DAC to any amp is double amping. It's not double amping in the conventional sense that involves a reduction in sound quality caused by the first amp. You also have full flexibility in terms of adjusting the output voltage via the digital volume control.

In my experience, the Mojo sounds far better than the Modi 2.

There are a few low sensitivity and/or high impedance headphones that can't be driven from the Mojo. (And electrostats should go without saying.) For example, I had a vintage piezoelectric (one of the rarest headphones in the world) that barely got loud enough from a Magni 2 Uber at max volume! But it's fine for most headphones.

I'm feeding it to my JBL 305 powered monitors. It's a clean source.

I did the same. I also used it as a preamp for a Behringer KM750 power amp and Klipsch RP-250F speakers.

 

[SilverEars]

Mojo LO mode is just line level voltage output(or volume level that matches the line level voltage, which was the same for the Hugo). The difference from a dedicated DAC compared to pre-amp is, with a pre-amp you are making adjustment to the output voltage that the receiving amp takes in to drive whatever is being driven. Output impedance of dedicated amp is higher than something like a mojo. Ideally, you want want an amp at the driving side to lower the output impedance which the dedicated amp is too high, and therefore you send the DAC's signal to the amp that lowers the output impedance.

Line-level output of a dedicated DAC is amp'd. With a dedicated DAC, although you can adjust the volume digitally by software, the output impedance is the issue which is reduced with an amp.

What I'm most concerned about is the noise I'm hearing with a dirty usb connection out of my desktop. With the Mojo, I feed in optical which isolates from such noise. Behringer UCA202 seems to be low cost option to isolate usb noise if you don't have an optical out on your computer.

 

[SilverEars]

I did the same. I also used it as a preamp for a Behringer KM750 power amp and Klipsch RP-250F speakers.

I had a set of passive loudspeakers in the past that I no longer own, and looking into getting a new pair(which performs very well from what I recall, and there is a difference from monitor(like JBL 305) output to what a loudspeaker can do). And the Behringer KM750 sounds like a very reasonably priced option to get ample power fed to them.

I had these, and these(mine were EMP tek, but same thing) were impressive for the price. https://rbhsound.com/towers_imp.php

JBL 305 can output clean sound, but it's not only about loudness per sizing of space that people generally point out. If you compare loudspeakers to these monitors, you will notice the differences. It's not really about speaker size fitting for room sizes, there is more to it than that. These monitor like speakers are limited in how the sound it output, it just sounds like miniature speakers although the tweeters sound clean in the case of JBL, you don't get as much of a weighty sound as you get from loudspeakers. You can hear the limitation with these small speakers with tweeter emphasis. Due to this, it lacks realism.

How did you run into the Behringer KM750?

 

[Music Alchemist]

Mojo LO mode is just line level voltage output(or volume level that matches the line level voltage, which was the same for the Hugo). The difference from a dedicated DAC compared to pre-amp is, with a pre-amp you are making adjustment to the output voltage that the receiving amp takes in to drive whatever is being driven. Output impedance of dedicated amp is higher than something like a mojo. Ideally, you want want an amp at the driving side to lower the output impedance which the dedicated amp is too high, and therefore you send the DAC's signal to the amp that lowers the output impedance.

Line-level output of a dedicated DAC is amp'd. With a dedicated DAC, although you can adjust the volume digitally by software, the output impedance is the issue which is reduced with an amp.

Chord DAC/amps are also digital preamps. The output voltage is adjusted by the digital volume control whether you are driving headphones or connecting to a speaker system.

(Just wanted to clarify, since your statements could be interpreted as saying otherwise. Oh, and I didn't mean they're preamps when you're driving transducers directly.)

What I'm most concerned about is the noise I'm hearing with a dirty usb connection out of my desktop. With the Mojo, I feed in optical which isolates from such noise. Behringer UCA202 seems to be low cost option to isolate usb noise if you don't have an optical out on your computer.

Yep, I was happy with using the UCA202 that way (the Mojo is the only DAC I tried optical with), and at the moment it's my temporary DAC as well.

I had a set of passive loudspeakers in the past that I no longer own, and looking into getting a new pair(which performs very well from what I recall, and there is a difference from monitor(like JBL 305) output to what a loudspeaker can do). And the Behringer KM750 sounds like a very reasonably priced option to get ample power fed to them.

I had these, and these(mine were EMP tek, but same thing) were impressive for the price. https://rbhsound.com/towers_imp.php

I think I'll focus on Tekton speakers from now on. The designer claims they're the most accurate speakers in the world despite the (relatively) affordable prices. I don't know how true that is, but the reviewers (and owners) are going crazy over them. The description of the technology is very interesting: http://www.tektondesign.com/about.html

JBL 305 can output clean sound, but it's not only about loudness in a space that loudspeakers do better compared to a monitor. If you compare loudspeakers to these monitors, you will notice the differences. It's not really about speaker size fitting for room sizes, there is more to it than that.

Studio monitors are loudspeakers too. Technically, all sorts of speakers (active, passive, small, large, etc.) can be studio monitors; it's just that many of them tend to be powered and compact. In some cases, the exact same floorstanding speaker with a different paint job / finish has been marketed as either a studio monitor or audiophile speaker.

And yeah, my towers sound way more realistic than the small monitors, but they're both great.

How did you run into the Behringer KM750?

I just researched affordable power amps.

The main downside (aside from its size and weight) is the loud fan system. It stays cool, but is not quiet at all.

I plan on sticking with it until I can get a digital power amp from Chord when it's released. (People are saying it will be like the speaker version of basically being able to drive headphones directly from the DAC, with the highest transparency/accuracy.) On that note, I'm still curious how well Chord DAC/amps can drive various passive speakers directly, since you can do that with the right cables. They're just limited in output power, so the speakers have to be fairly sensitive.

 

[Hooster]

My perspective is that if you want to call it double amping, you might as well say connecting any DAC to any amp is double amping. It's not double amping in the conventional sense that involves a reduction in sound quality caused by the first amp.

"Any DAC" is not able to function as a headphone amplifier as well as the Mojo does. The Mojo is a headphone amplifier, advertised, sold and used as such. Any dac is not. It is surprising to see how much confusion there still seems to be about this.

An amplifier downstream will always affect the sound quality and it will unavoidably be different from the sound without it. Sorry for being captain obvious here, but there would be zero point if there was no difference. The thousand $ question is, do you like the difference and is it worth the extra clutter and expense?

 

[Music Alchemist]

"Any DAC" is not able to function as a headphone amplifier as well as the Mojo does. The Mojo is a headphone amplifier, advertised, sold and used as such. Any dac is not. It is surprising to see how much confusion there still seems to be about this.

Well yeah, any Chord enthusiast knows that. What I'm saying is that the amplification in Chord DAC/amps is not going to compromise the sound quality when connected to another amp, so although it's technically double amping, it's not "conventional" double amping. This is a crucial distinction, because many amps do color the sound when used as preamps.