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Review and Measurements of Schiit Jotunheim and iFi iDSD Black Label DACs and Headphone Amps

amirm

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#1
This is a review, detailed measurements and comparison of Schiit Jotunheim Headphone Amplifier (with its optional Multibit DAC) and iFi iDSD Black Label DAC and Headphone amplifier. Both are on kind loans from members and arrived on the same day. Seeing how their prices are similar, I decided to compare them to each other. The iFi however, has built-in battery, is far smaller and less power hungry, making it suitable for portable use in addition to desktop. The Jotunheim on the other hand, is firmly a desktop product, in a pretty heavy case for its size and is mains powered. Here they are together:

20180713_172218.jpg


I say the minimalist look of Schiit products is best represented in this form factor. I also like the heft and feel of the large volume control.

The ifi is quite cute and nicely done from style point of view. Alas, I don't like switches spread everywhere on the side and bottom. Placement is more optimized though so perhaps that is good for performance.

As mentioned, the Schiit Jotunheim came with its optional DAC board. With the included DAC it retails for USD $599 plus shipping direct from Schiit (they don't sell any other way). The iFi iDSD Black Edition seems to be listed at the same price. So it is a fair comparison from that point of view.

Both worked in plug-and-play mode with Windows 10 Creators edition. For measurements I used ASIO4ALL to create an ASIO interface for my Audio Precision analyzer software to control them. For listening, I used WASAPI interface in Roon player.

iFi iDSD Black supports DSD up to 512 whereas Schiit Jotunheim DAC does not support DSD at all. On the other hand, the Schiit Jotunheim has both balanced analog inputs and outputs in addition "balanced" headphone out. I did not test any of the balanced functionality in this review.

I am sure you are all anxious to see how they measure so let's get into that:

Measurements
Let's start with our usual Dashboard of iFi iDSD Black:

ifi idsd Black DAC Dashboard Measurement.png


I have set the level of the headphone output to 2 volts to more or so match the nominal RCA DAC outputs. At 93 SINAD (signal over distortion+noise) fidelity is respectful. No, it is not at the state-of-the-art desktops that go 110 dB and beyond but pretty good for a portable USB DAC with headphone output.

Switching to Jotunheim, we see clearly reduced performance at the same 2 volt output:
Schiit Jotenheim DAC dashboard as is measurement.png


We lose 10 dB of SINAD. And we see that mains hum in the FFT spectrum as indicated.

The story does not end here though. By chance, I put my hand on the Jotunheim while having my other hand on the metal case of my laptop and to my amazement saw that mains hum go right down! What the heck???

I disconnect power and pull out the power and check for grounding. I first test to see if there is continuity between mains safety ground and unbalanced/RCA signal ground:

Schiit Jotunheim RCA mains grounded.jpg


We get 0.2 ohms which essentially says they are connected. Now the same test but this time with the upper part of the case:
Schiit Jotunheim Case not grouned hum.jpg


Yup. "OL" means open load or no connection whatsoever! Notice how I am poking my sharp leads into the drilled holes of the upper case. There is some kind of coating on it that insulates electricity which I suspect the reason it is not grounded. However it is screwed to the bottom (which is grounded), there is no electrical connection.

So I ground the upper case using the same drilled holes to the RCA connection as such:
Schiit Jotunheim hum fix Case jumper.jpg


And our dashboard now shows:

Schiit Jotenheim DAC dashboard case grounded measurement.png


Look at the FFT. The mains hum is gone, gone, gone! The worse channel (#2) shows 1.6 dB of improvement in SINAD. All with a 10 cent wire jumper!

Note that the difference was more dramatic at other times.

The Jotunheim like other Schiit products uses an EI core transformer (as opposed to toroidal) so it is essential that the entire case is grounded to keep the magnetic field from coupling into the audio circuit.

More important, this is a three-pronged mains input in a device with metal case. This means it is NOT double insulated and as such, from safety/UL point of view, it most definitely needs to have the entire chassis connected to mains safety ground. Should the hot lead come in contact with the upper case holes, it will energize it and no circuit breaker will trip! Yes, it is a one in a million chance of happening but if it happens to you, it will be a one in one chance. :)

This problem needs immediate investigation by Schiit. I suggest that owners get an ohm meter with sharp probes and repeat my test above. If you get an open load as I did, contact Schiit and ask them to investigate and repair.

Anyway, let's continue with distortion versus frequency measurement:
ifi idsd Black DAC vs Schiit Jotunheim DAC THD vs Frequency Measurement.png


Once again, the iFi DSD Black provides competent performance whereas the Schiit has that odd rising distortion with frequency. 0.3% distortion at 20 kHz in this day and age? Really? This is unacceptable. It is likely running out of gain to provide feedback and reduce distortion.

Here is the intermodulation distortion versus input level:
ifi idsd Black DAC vs Schiit Jotenheim DAC IMD Measurement.png


Looks like one channel in iFi iDSD Black is noisier than the other. As the signal gets larger, that difference gets lost in the noise literally and performance is good. But again, not in desktop category as shown by the Oppo UDP-205 -- one of the best measuring DACs out there (really a UHD Blu-ray player). The Schiit Jotunheim underperforms the iFi iDSD Black by 10 dB or so. This is very significant difference.

How about jitter and noise?
ifi idsd Black DAC vs Schiit Jotunheim DAC Jitter Measurement.png


While iFi iDSD Black outperforms the Jotunheim by 10 dB again in noise, the latter seems to have a decent performance too. So not much to complain about.

And oh, here is the frequency response for iFi at 44.1 kHz CD sampling:

ifi idsd Black DAC Frequency Response Measurement.png


And Schiit Jotunheim:

Schiit Jotenheim DAC frequency response measurement.png


The reconstruction filter in the DACs rolls off the highs in both starting at 17 kHz. Not an issue for us older folks but for younger crowd, it would be good to have this be a couple of kilohertz higher.

As headphone amplifiers, probably the most important measurement is distortion versus output power. These are newly styled measurements that show the power directly. They rely on me remembering to set that parameter correctly which I think I have (crossing fingers). First at 300 ohm load to simulate a headphone like Sennheiser HD-650:
ifi idsd Black DAC vs Schiit Jotunheim Headphone Power at 300 ohm Measurement.png


The iFi iDSD Black yet again shows off its lower noise but I was very surprised to see it outperform the Schiit Jotunheim on power! The iFi is a USB powered product folks. Yet it is pushing more power and cleaner level than Schiit Jotunheim which seems to have some kind of internal limiting.

Stepping down to 150 ohm we get this:

ifi idsd Black DAC vs Schiit Jotunheim Headphone Power at 150 ohm Measurement.png


Same differential in performance in favor of iFi.

And 33 ohm:

ifi idsd Black DAC vs Schiit Jotunheim Headphone Power at 33 ohm Measurement.png


Amazing. The iFi continues its lead at all output loads/impedances.

Finally, let's look at channel imbalance as I in real-time adjust the volume control and the analyzer plots the power (at 300 ohm load) versus channel imbalance. First iFi iDSD Black:

ifi idsd Black DAC channel imbalance a 300 ohm Eco gain Measurement.png


I put both units in their lowest gain mode because that is the most useful scenario. There, the error for the iFi is below 0.3 dB or so until the very end/minimum level. Audibly you can easily tell one channel cuts out earlier than the other in high-gain mode. In low/eco mode, it is much, much less noticeable. With three different gain settings, I don't think this is a problem for the iFi.

Here is Schiit Jotunheim:

Schiit Jotunheim DAC channel imbalance a 300 ohm low gain Measurement.png


The Jotunheim is more well behaved here with channel balance maintained much better at the limit.

Output impedance was excellently low in both with iFi landing at 0.9 ohms and Jotunheim at 0.8 ohms.

Let's get into how they sound.

Listening Tests
I usually perform level match testing of headphones. This time I thought I do as others do, listen to music and quickly switch the headphone jack back and forth (playback is ganged through Roon). Even though the tests are sighted and obviously not level matched, I think the results mirror measurements pretty well because focus is on power delivery and clarity. Then again, they may just be my imagination so read with caution! :)

I started my testing with my Sennheiser HD-650 headphones. I seem to never have enough power to drive these. Well, that changed with this review.

I started with my electronic tracks which I find most revealing with headphones and headphone amps. To wit, this track from 20 KID: https://suiciderobot.bandcamp.com/track/switch

Here is another one of their tracks:

I must say, I didn't there was a such a thing as "subwoofer for your ears" but this is the best analogy I can come up with when driving the HD-605s with iFi iDSD Black. At mid-levels before pain sets in, you can feel your ear lobes vibrating and the headphone cups taking flight! Yes, the cans start to physically vibrate back and forth. It was an incredible and highly satisfying experience I had not had with headphones!

What is that? Speak up, I can't hear you! :D Yes, it was loud, but not too loud for a few seconds of testing.

Too loud came after turning up the level even more! :D:D It now feels like my head is inside the drums. What an experience. If I did not fear permanent hearing loss, I would listen like this all day! I must say, the sound stayed clean until I got too scared to turn it up further.

I then switched to Schiit Jotunheim. It too had incredible power able to make the headphone cups run for their lives. Alas, the bass is less clear and distinct than the iFi. And highs have this smeary slightly weird sound to them.

Mind you, the extra power of the Jotunheim is quite a bit more satisfying than lower distortion but lower power headphone amps. It is just that in the presence of the iFi iDSD Black, it had power but without the finesse. So I can understand the praise this unit gets.

I should say that the iFi iDSD Black as the measurements showed, has more power and headroom than Jotunheim.

Next I switched to a low impedance Grado SR60e. With ifi at low volume the experience is quite satisfying with highly dynamic sound. Turn up the volume just a quarter though (in "turbo" or highest gain mode) and the Grado starts to cry. The drivers start to rattle and buzz. Prior to that there is a transition period where distortion sets in. It is fascinating to see the headphone distort well before the amplifier does.

Using the Gradoes with Jotunheim was unpleasant after listening to iFi drive them. High frequencies are more distorted at almost all listening levels.

Next was Sony MDR-V6. At more than a quarter volume with the iFi, it felt like the drivers were going to tear up! These headphones simply can't handle power. Driving them with Jotunheim delivered a dull experience in contrast. Detail and distinction in bass gets lost due to the amp and the driver distortion screws up the rest.

Last but not least is HiFiman HE400i. What a delight these headphones are. As with Sennheiser HD-650s, they easily handle enough power for the cans to take flight and your hearing anatomy dance to the pressure waves of the music! Distortion was so low that I could turn the volume enough until my cheeks started to resonate with music! Too scared to push the volume above 2:00 o'clock position.

The experience with Jotunheim was muddy and dull again. Yes, the power is there to rattle my teeth just fine. But the overall fidelity simply is not there compared to iFi iDSD Black. As you turned up the volume to the end, distortion gets really bad and obvious. This is in sharp contrast to the iFi which would deliver clean power to the extreme.

Conclusions
It was great to test these two high-power headphone amplifiers. They forever changed my experience and expectation of headphone amplifiers. Between the two, the iFi iDSD Black Edition is a clear winner. It is so both in objective measurements and subjective listening tests across multiple headphones.

The lack of upper lid grounding in Jotunheim is a safety concern and likely the cause of hum and noise in its user base. It produces higher distortion and noise which I find audibly objectionable. It also generates fair bit of heat. The top is borderline too hot to put your hands on.

In sharp contrast, the iFi iDSD Black barely gets warm and delivers power that belies its diminutive size. The fact that this much performance is also portable with battery power, is incredible. As such, iFi iDSD Black Edition gets my strongest recommendation in headphone DACs and Amplifiers. Well done iFi.

-------------

As always, questions, comments, recommendations, etc. are welcome.

If you like this review, please consider donating funds for these types of hardware purchases using Patreon (https://www.patreon.com/audiosciencereview), or upgrading your membership here though Paypal (https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054).
 
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amirm

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#2
I forgot to mention. If you don't know where to buy the jumper cable, I have three versions I am offering for sale:

1. The yellow one you see in the picture. You can buy them for 10 cents on ebay but because I will be selling them, the price is $10.

2. A 99% oxygen-free cable with hand forged alligator clips. I will be offering these for $399.

3. The ultimate version made out of free-radical-free insulation, cryogenically treated, electron aligned conductors. It is built by nude virgins on a remote island so it does not come cheap. For ASR members, I am offering this at a special price of $9999.

All three will objectively improve the fidelity of Schiit Jotunheim. Unlike any other cable you have bought before.

Product will be shipped on first come, first serve basis. It is not available in Hawaii or Alaska or anywhere not allowed by law.
 
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#3
The grounding issue is very interesting to see. A few people on Head-Fi mentioned noise issues. One thing that's particularly easy to test is this:
  • Unplug everything
  • Plug in the power cord
  • Plug in headphones (and wear them)
  • Set gain to high
  • Select the single ended inputs
  • Turn on the amp and wait for the muting relay to disengage
  • Carefully turn the volume up as much as seems right (I turned it up all the way with my single ended Focal Listen and my balanced Ether Flow)
  • You probably hear a slight buzz, at least with sensitive headphones
  • Touch the volume knob with one had
  • You probably hear a lot more noise. Experiment with approaching or touching cables, USB power supplies, laptop power supplies, other switchers, ...
  • Try just hovering your end above the case
  • Now touch something grounded with your other hand, like the bottom part of the Jotunheim, a metallic power strip, etc. The noise should disappear or at least be reduced.
Would be very interesting to see whether that goes away with your grounding fix. I was wondering whether I could somehow ground the top with the bottom.

The Jotunheim has a special case design where the only screw is the one for the volume knob. You unscrew that one, remove the volume knob, then slide off the top. Apparently that leads to insufficient grounding to the rest of the case.

In your listening tests, did you use the built-in DACs only? Both devices have a line-in input. While that will rarely be how the iDSD gets used, the Jotunheim can be bought without a DAC for $399.

You may want to specify that for $599, you get the multibit DAC module (essentially a Modi Multibit).

Edit: better instructions (might be good to turn the amp on)
 
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amirm

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#4
One other thing, if you turn up the volume to max on Jotunheim, while using a sensitive IEM, you can easily hear hiss and noise from your computer. Removing the USB cable eliminates it so it is definitely bleeding through the USB connection.

The ifi iDSD Black is dead quiet even at max volume.
 

amirm

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In your listening tests, did you use the built-in DACs only? Both devices have a line-in input. While that will rarely be how the iDSD gets used, the Jotunheim can be bought without a DAC for $399.
Yes, I only listened with the USB DAC. I will do more listening tests with the amp alone and report back the results.
 

amirm

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The Jotunheim has a special case design where the only screw is the one for the volume knob. You unscrew that one, remove the volume knob, then slide off the top. Apparently that leads to insufficient grounding to the rest of the case.
Thanks. I was wondering how it was held as I could not see any screws.

I have permission from the owner to open it up so will do so and report back.
 
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#7
Thanks. I was wondering how it was held as I could not see any screws.

I have permission from the owner to open it up so will do so and report back.
Nice! Instructions with pictures, courtesy of TheViolentVicar on Head-Fi (Source)
Definitely be careful with the LED when putting it back together. Schiit is working on using light pipes to make that less of a pain in the ass.
 
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#9
Sorry for the spam, but can you find out when the amp was bought? Was it bought with the DAC module, or was that installed after the fact? On SBAF, there were some claims that newer Jotunheims sound different from older ones. The old ones have a reputation of being a bit bright / harsh up top.
 

amirm

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Sorry for the spam, but can you find out when the amp was bought? Was it bought with the DAC module, or was that installed after the fact? On SBAF, there were some claims that newer Jotunheims sound different from older ones. The old ones have a reputation of being a bit bright / harsh up top.
I will ask the owner and report back.

For now, they claim the sound was improved but the model number not changed???
 

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I opened the lid and there is no prayer of that ever getting grounded. The pins that mount it to the rest of the box are insulated. And where they seat, is also painted. So every unit is going to have the hum issue and it is just a matter of how bad it is for it to be audible.
 

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#13
also, headphone out power with the xlr out?
I have not yet built by balanced cable for measurements. If I can get it done soon, yes.
 
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I will ask the owner and report back.

For now, they claim the sound was improved but the model number not changed???
SBAF claims so, yes. If have yet to read any comment from Schiit on that. But Schiit is known to silently make small updates to their products over time, for various reasons, like parts availability.
 
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#15
i actually own an old and new version. one from close to release and a newer one from feb this year. there is imo a sound difference between them.
 

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#16
Some more background on that special case (towards the end of that post). The new Lyr 3 has a similar design, and therefore possibly the same issue.
Or to save reading a huge pile of incredibly masturbatory writing:
Or, in other words, the chassis was intended to reduce cost.

Or, put bluntly: to be cheaper.
Worth noting that the good (not great) performance of the iFi device is provided by a 10ish year old Burr Brown PCM1793 DAC. So you can have "multibit" and decent performance, and there's no need to use super secret "mil spec" DACs and overhyped burrito filters.

Amir, where are your (in)famous linearity measurements for these?
 
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#17
i actually own an old and new version. one from close to release and a newer one from feb this year. there is imo a sound difference between them.
Can you do the noise test I outlined? Just curious.

I had two until recently (now one), though both shipped in November 2017. Still, I noticed that the time it takes for the muting relay to disengage after turning it on is very different between the two (also on shutdown, but that's less important). Time from turning on to end of relay clicks is 23s for one, 32s for the other. Time from turning off to first relay click is 15s for one, 28s for the other.
 

amirm

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@amirm
can you check a low level sine wave for glitch with the schiit dac? also, headphone out power with the xlr out?
Here you go. For quickness, I connected the Schiit Jotunheim using its balanced output at 4 volts, and ifi iDSD using its RCA outs at 2 volts (so ignore the amplitude differences). The signal is -80 dB. -90 dB was way too messy. :)

ifi idsd Black DAC vs Schiit Jotunheim DAC -80 db Linearity Measurement.png


Those are some serious errors out of the Schiit's multibit DAC (in red). There are clear glitches as it goes up in level and then noise on top of that.

The ifi is so much cleaner (in green).
 

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Amir, where are your (in)famous linearity measurements for these?
I usually don't run that on headphone amps but since these are also DACs, I will run it tomorrow. For now, you can predict the issues from above measurements. :)
 

amirm

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#20
I had two until recently (now one), though both shipped in November 2017. Still, I noticed that the time it takes for the muting relay to disengage after turning it on is very different between the two (also on shutdown, but that's less important). Time from turning on to end of relay clicks is 23s for one, 32s for the other. Time from turning off to first relay click is 15s for one, 28s for the other.
One relay clicks at 9 seconds, the second at 19. What does that mean?
 
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