• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). Come here to have fun, be ready to be teased and not take online life too seriously. We now measure and review equipment for free! Click here for details.

Budget DAC Review: Schiit Modi 2 ($99)

DonH56

Master Contributor
Technical Expert
Forum Donor
Joined
Mar 15, 2016
Messages
5,566
Likes
9,832
Location
Monument, CO
I would expect the issue with computer activity to be driver-related (?)

I too would like to see a 16-bit trial at a couple of sample rates. I wonder if the SRC is messing it up... Could also be how they are handling the 24-to-16-bit conversion but unless something is really hosed that shouldn't corrupt the bits that are there. And yah seems like there is no buffering; with this DAC that would have to be added externally (I think some DAC chips include a FIFO on-chip but have not looked at audio DACs much). And maybe there's simply no clock buffering/isolation/resynch so you get GIGO.

Interesting that your previous test of their $400 DAC also had issues. Strange, 2 kHz (small k, capital H, I'll nag you 'til you get it right ;) ) and 19 kHz or so are rather odd spur frequencies for an 11 kHz tone sampled at 44.1 kS/s. Almost like harmonics around 40 kS/s instead of 44.1 kS/s. I've put in 90+ hours working this week so maybe brain-fade is causing me to miss something obvious...

I'd be really surprised if they were interleaving the two channels to create a balanced output; for balanced output the usual solution is just one more op-amp or inverting buffer. Often just one quad op-amp to do it all (inverting and non-inverting outputs for each channel). Much easier than ping-ponging DACs.
 

Blumlein 88

Master Contributor
Forum Donor
Joined
Feb 23, 2016
Messages
12,449
Likes
18,754
I would expect the issue with computer activity to be driver-related (?)

I too would like to see a 16-bit trial at a couple of sample rates. I wonder if the SRC is messing it up... Could also be how they are handling the 24-to-16-bit conversion but unless something is really hosed that shouldn't corrupt the bits that are there. And yah seems like there is no buffering; with this DAC that would have to be added externally (I think some DAC chips include a FIFO on-chip but have not looked at audio DACs much). And maybe there's simply no clock buffering/isolation/resynch so you get GIGO.

Interesting that your previous test of their $400 DAC also had issues. Strange, 2 kHz (small k, capital H, I'll nag you 'til you get it right ;) ) and 19 kHz or so are rather odd spur frequencies for an 11 kHz tone sampled at 44.1 kS/s. Almost like harmonics around 40 kS/s instead of 44.1 kS/s. I've put in 90+ hours working this week so maybe brain-fade is causing me to miss something obvious...

I'd be really surprised if they were interleaving the two channels to create a balanced output; for balanced output the usual solution is just one more op-amp or inverting buffer. Often just one quad op-amp to do it all (inverting and non-inverting outputs for each channel). Much easier than ping-ponging DACs.

I may have been confusing in my description. The DAC used in the Modi is one chip with two DACs. I think in the more expensive DAC they use this in they use two of the chips and each of them is in balanced configuration. I saw comments elsewhere suggesting they were using this one chip (you can see in pictures the Modi has only one 5547 chip) also balanced, running at double speed and switching between channels. Normally I would expect each DAC in the chip to be run single ended and supply one channel each.
 
OP
amirm

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
34,925
Likes
129,528
Location
Seattle Area
Here is a simple 7 Khz tone at 44.1 Khz/16 bits:

Schiit Modi 2 vs iFi iDAC2 at 7 Khz 441.png


Looks like the same story. The only new info is the elevated second harmonic from iFi iDAC2. Its output level is higher than Modi so it is not as bad as it looks but still, that is a pretty high harmonic distortion for the iFi.

All I did to generate these two graphs is to change the output device in Foobar2000 which is the player I am using. There could still be mistakes but I don't know that it is worth messing with it more. The Schiit Modi 2 is just not well designed to isolate against noise and jitter induced into it.
 

RayDunzl

Master Contributor
Central Scrutinizer
Joined
Mar 9, 2016
Messages
11,506
Likes
12,126
Location
Riverview FL
What's inside?

Where's the Photographer?
 
OP
amirm

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
34,925
Likes
129,528
Location
Seattle Area
OP
amirm

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
34,925
Likes
129,528
Location
Seattle Area
Oh wait... This thing does not say it supports Async mode via USB! If so, those spikes could be USB buffer refills!
 

RayDunzl

Master Contributor
Central Scrutinizer
Joined
Mar 9, 2016
Messages
11,506
Likes
12,126
Location
Riverview FL
Last edited:

Blumlein 88

Master Contributor
Forum Donor
Joined
Feb 23, 2016
Messages
12,449
Likes
18,754
Hold on a minute here. I didn't realize there were so many versions of the Modi 2.

The $99 and $149 (Uber) versions are listed as having the AK4490. The $249 Modi Multibit has the AD5547 chip in it.

http://schiit.com/products/modi-2

I also see they offer an ASIO download package though it isn't clear if it applies to the Modi. I wonder if performance improves with that? Very bottom of this page.

http://schiit.com/drivers

Apparently from info elsewhere, the Modi 2 used dual AKM 4339 chips until around June of last year when the single AK4490 started showing up.
 
Last edited:

watchnerd

Master Contributor
Joined
Dec 8, 2016
Messages
11,462
Likes
8,922
Location
Seattle Area, USA
Give me bloody time! :D Have it open now.

The DAC chip is different! It is an AK4490EQ, not Analog devices!!! http://www.akm.com/akm/en/product/datasheet1/?partno=AK4490EQ

In quantity it is $1.50.

Talk about misleading advertisement:
View attachment 6927

I wouldn't call that misleading -- it's a different model.

There are 3 different Modis:

Modi 2, Modi 2 Uber, Modi Multibit

If you read the spec sheet it's plain that they're different models:

"D/A Conversion IC:

Modi 2 and Modi 2 Uber: AKM AK4490
Modi Multibit: Analog Devices AD5547"
 

Phelonious Ponk

Addicted to Fun and Learning
Joined
Feb 26, 2016
Messages
859
Likes
202
In this day and age, when capable, reasonably transparent DACs are small parts of devices like phones, streamers, bluetooth speakers, etc., is any free-standing DAC, even at just $99, really a "budget" DAC? If it deserves a box of its own, it should be "hi fi." It should deliver something audibly superior to the DAC that is an incidental component of my phone. And this doesn't appear to do that. Schitt indeed. Five figure DACs in multiple boxes? Bullschitt.

Tim
 

watchnerd

Master Contributor
Joined
Dec 8, 2016
Messages
11,462
Likes
8,922
Location
Seattle Area, USA
In this day and age, when capable, reasonably transparent DACs are small parts of devices like phones, streamers, bluetooth speakers, etc., is any free-standing DAC, even at just $99, really a "budget" DAC? If it deserves a box of its own, it should be "hi fi." It should deliver something audibly superior to the DAC that is an incidental component of my phone. And this doesn't appear to do that. Schitt indeed. Five figure DACs in multiple boxes? Bullschitt.

Tim

It makes me wonder about the point of a $100 DAC. It's not really much better than a built-in DAC on something else.
 

Cosmik

Major Contributor
Joined
Apr 24, 2016
Messages
3,075
Likes
2,101
Location
UK
What would be the "free" option? Dac on the computer motherboard? Or DAC in an Audio/Video Receiver?
Archimago has found that iPhone and iPad on-board DACs are good, but many laptop motherboards are not - I think generally for reasons of grounding and system noise. I am sure AV receiver and dedicated streamer DACs are good, with the main determinant of ultimate quality being the type of link you are using - asynchronous links being best for jitter-free performance.

As you have pointed out, a top notch DAC IC costs $1.50 and only needs a few other components to complete it. You are paying extra for 'maverick' designers to mess it up by using it wrongly.

Possibly the main problem with digital audio is not the audio performance of the DACs themselves, but the issue of the compatibility of various devices, software, drivers etc. and that people are often not quite sure whether there's any unnecessary jitter or re-sampling going on.
 

Blumlein 88

Master Contributor
Forum Donor
Joined
Feb 23, 2016
Messages
12,449
Likes
18,754
Archimago has found that iPhone and iPad on-board DACs are good, but many laptop motherboards are not - I think generally for reasons of grounding and system noise. I am sure AV receiver and dedicated streamer DACs are good, with the main determinant of ultimate quality being the type of link you are using - asynchronous links being best for jitter-free performance.

As you have pointed out, a top notch DAC IC costs $1.50 and only needs a few other components to complete it. You are paying extra for 'maverick' designers to mess it up by using it wrongly.

Possibly the main problem with digital audio is not the audio performance of the DACs themselves, but the issue of the compatibility of various devices, software, drivers etc. and that people are often not quite sure whether there's any unnecessary jitter or re-sampling going on.

The reason they are unsure is the method of evaluating such gear. Plus a gross poor judgement about what is most important for quality sound. Abetted by those making money off the situation.

There are $500 DACs that don't appear to give up much of anything in basic performance parameters. There are some $350 devices you can say that about. Some of them being recording interfaces which include ADC/DAC chips for more than two channels. Amir is looking for $100 or so units that might also manage it. The search isn't going well so far.

The DAC chips are a few dollars. I don't know how to gage cost of an effective inexpensive power supply though suspect it isn't much. The convincing case might well be the most expensive part of inexpensive DAC units. Then brand building ads and such. Though I don't have hands on a currently available unit that does a good enough job at $250 I am pretty sure it could and probably is being done. The contenders can be picked with your basic measurements like Amir is doing. This isn't a situation that can be effectively replaced with listening and subjective impressions of the sound.

I think the recording interfaces are instructive. They generally are solid products with good sound and solid measured performance for not much money. The companies are not using maverick designers or playing quite so much with buzz words for people's attention. They have performance goals and see the product meets them. They also once they have worked out how to do a particular circuit which is used all up and down a product line rather than designing everything special and from scratch. Not that those are immune form buzzwords or marketing just not nearly so much as consumer playback gear.
 

Cosmik

Major Contributor
Joined
Apr 24, 2016
Messages
3,075
Likes
2,101
Location
UK
The reason they are unsure is the method of evaluating such gear.
What I mean is that if you plug a DAC into a PC without being an IT guru, you are often not sure whether it is installing a generic driver, or the manufacturer's driver, or whether it is running isochronous or asynchronous, resampling everything to 48 kHz etc. etc. Different apps may interface with the driver in different ways. System updates may overwrite a previously blameless setup.
 

Phelonious Ponk

Addicted to Fun and Learning
Joined
Feb 26, 2016
Messages
859
Likes
202
"The convincing case might well be the most expensive part of inexpensive DAC units. Then brand building ads and such."

And yet in this case there is little of this, beyond snarky naming and the reliable gullibility of the Computer Audiophile community.

Tim
 

DonH56

Master Contributor
Technical Expert
Forum Donor
Joined
Mar 15, 2016
Messages
5,566
Likes
9,832
Location
Monument, CO
It makes me wonder about the point of a $100 DAC.

Money. There's a market for it, bolstered by all sorts of marketing saying whatever DAC is in your component, an external DAC is better. It must be; it's external, it's a dedicated single-purpose device, and "separates" must always be better than something "inside". :cool:

It's not really much better than a built-in DAC on something else.

And apparently sometimes worse.
 
Top Bottom