Schiit Audio Aegir power amplifier Measurements

Sidebar 3: Measurements

I performed a full set of measurements on the Schiit Aegir, using my Audio Precision SYS-2722 system (see the January 2008 "As We See It"). Before doing any testing, I preconditioned the Aegir by running it at one-third power into 8 ohms for an hour. At the end of that time, the side-mounted heatsinks were hot, at 114.3°F (45.8°C) toward the rear, a little cooler nearer the front.

The Schiit's voltage gain into 8 ohms was slightly lower than the specified 22dB, at 19.5dB for both unbalanced and balanced inputs, the latter measured with the speaker output taken from the two hot terminals as described in the manual. The amplifier preserved absolute polarity (ie, was noninverting) for both modes of operation, the latter with the positive speaker connection made to the right channel's hot binding post, the negative to the left channel's post. (According to the amplifier's rear panel, the XLR is wired with pin 2 hot.) The single-ended input impedance is specified as 22k ohms. However, I measured 11.5k ohms at low and middle frequencies, dropping to 10k ohms at 20kHz. The balanced input impedance was twice the unbalanced, as expected.

The Aegir's output impedance was fairly low, at 0.125 ohm at 20Hz and 1kHz, rising very slightly to 0.15 ohm at 20kHz. As a result, the response with our standard simulated loudspeaker varied by just ±0.1dB (fig.1, gray trace). his graph shows that the audioband response into 8 ohms (blue and red traces) is flat up to 20kHz, with an ultrasonic rolloff reaching –3dB at 180kHz. The two channels are closely matched, and the Aegir reproduced a 10kHz squarewave with very short risetimes and no overshoot or ringing (fig.2). A 1kHz squarewave was perfectly square (fig.3).

919SchAegirfig01

Fig.1 Schiit Aegir, frequency response at 2.83V into: simulated loudspeaker load (gray), 8 ohms (left channel blue, right red), 4 ohms (left cyan, right magenta), 2 ohms (green) (1dB/vertical div.).

919SchAegirfig02

Fig.2 Schiit Aegir, small-signal, 10kHz squarewave into 8 ohms.

919SchAegirfig03

Fig.3 Schiit Aegir, small-signal, 1kHz squarewave into 8 ohms.

Channel separation was very good, measuring >90dB in both directions below 1kHz, and still 67dB at 20kHz (fig.4). Perhaps because of the low gain, the wideband, unweighted signal/noise ratio, ref. 2.83V and measured with the input shorted to ground, was a high 88dB in the left channel and 81.4dB in the right. These ratios improved to 93dB when the measurement bandwidth was restricted to the audioband, and to 101dB when A-weighted. Spectral analysis of the Aegir's noise floor (fig.5) revealed spuriae both at 120Hz and its harmonics, and at 60Hz and its odd-order harmonics. All of these spuriae are very low in level, however, and will not be audible.

919SchAegirfig04

Fig.4 Schiit Aegir, channel separation (dB/vertical div.).

919SchAegirfig05

Fig.5 Schiit Aegir, spectrum of 1kHz sinewave, DC–1kHz, at 1W into 8 ohms (linear frequency scale).

Schiit specifies the Aegir's maximum power as 20Wpc into 8 ohms and 40Wpc into 4 ohms, both equivalent to 13dBW with our convention of referencing all powers to 1W into 8 ohms. With "clipping" defined as when the THD+noise reaches 1%, fig.6 indicates that with both channels driven, the Aegir exceeded its specified power into 8 ohms, clipping at 28Wpc (14.5dBW). Into 4 ohms (fig.7), the Aegir again exceeded its specification, delivering 43Wpc (13.3dBW) at 1% THD+N. Figs. 4 and 5 indicate that the distortion is very low at all powers below clipping. In mono output mode, Schiit says that the Aegir will deliver 80W into 8 ohms (19dBW). With a balanced, bridged output, the maximum voltage swing is twice that of each individual stage, meaning that the potential maximum power is increased by a factor of four. However, when I measured the maximum power delivery in mono mode, the Aegir's protection circuitry cut off the output at 49Wpc into 8 ohms (17dBW, fig.8).

919SchAegirfig06

Fig.6 Schiit Aegir, both channels driven, distortion (%) vs 1kHz continuous output power into 8 ohms.

919SchAegirfig07

Fig.7 Schiit Aegir, both channels driven, distortion (%) vs 1kHz continuous output power into 4 ohms.

919SchAegirfig08

Fig.8 Schiit Aegir, bridged-mono mode, distortion (%) vs 1kHz continuous output power into 8 ohms.

The Schiit Aegir offered very low levels of distortion into 8 ohms (fig.9, blue and red traces) for most of the audioband, but with the usual increase in the top two octaves, due to the corresponding reduction in open-loop gain margin. The distortion increased into 4 ohms but to a greater extent in the left channel (cyan trace) than the right (magenta). The waveform of the residual distortion and noise (fig.10) suggests that the subjectively benign second harmonic is dominant, though spectral analysis (fig.11) indicates that the third harmonic is only a few dB lower in level. Tested with an equal mix of 19 and 20kHz tones at one-third power into 8 ohms, the second-order difference product lay below –100dB (0.001%) in both channels (fig.12). However, the levels of higher-order intermodulation products were higher, though still low, at –80dB (0.01%). When I kept the output voltage the same and halved the load impedance, the higher-order products remained at the same levels, though the difference product rose to a still-negligible –86dB (0.005%).

919SchAegirfig09

Fig.9 Schiit Aegir, THD+N (%) vs frequency at 6V into: 8 ohms (left channel blue, right red), 4 ohms (left cyan, right magenta).

919SchAegirfig10

Fig.10 Schiit Aegir, 1kHz waveform at 6Wpc into 8 ohms, 0.0022% THD+N (top); distortion and noise waveform with fundamental notched out (bottom, not to scale).

919SchAegirfig11

Fig.11 Schiit Aegir, spectrum of 50Hz sinewave, DC–1kHz, at 8Wpc into 8 ohms (linear frequency scale).

919SchAegirfig12

Fig.12 Schiit Aegir, HF intermodulation spectrum, DC–30kHz, 19+20kHz at 8Wpc peak into 8 ohms (linear frequency scale).

I was pleasantly surprised by the Schiit Aegir's measured performance. It is a well-engineered amplifier at an affordable price.—John Atkinson

COMPANY INFO
Schiit Audio
24900 Anza Drive, Unit A
Valencia, CA 91355
(323) 230-0079
ARTICLE CONTENTS

COMMENTS
Anton's picture

Every once in a while, I will cross paths with a review that makes me wanna stop what I am doing, run out to a dealer, and impulse buy the product.

This is one of those times.

I am already trying to envision where I would put it!

I have a little loft above the barn with a pair of Heresy speakers and a pair of Infinty Intermezzo 2.6 speakers (purchased thanks to an ancient review from Stereophile!) that I am running with an Oppo 205 into an SMSL 98 dollar amp....and it sounds great. I'm thinking this piece of Schiit plus a home brew preamp a friend is building may be just the ticket...and affordable!

That's some good Schiit!

invaderzim's picture

It does get more dangerous when the items being reviewed are priced like this.
I like the looks, I like the size and I respect Herb's take on the sound.

Bogolu Haranath's picture

The least expensive Class-A amplifier in the Stereophile 2019 October recommended components list, Schiit Audio Aegir ($799) .......... That is excellence in engineering :-) .........

Bogolu Haranath's picture

May be HR could also review the new Schiit Audio Freya+ ($899) pre-amp? :-) ...........

Travis's picture

This review is confusing to me. What preamp were you using, the 5K RP-7? Also, when hooking up headphones to the Schiit, how did you control the volume level. It doesn't have volume control, does it?

Thanks.

Herb Reichert's picture

I used the Rogue Audio RP-7 preamp

it is a fairly neutral but also radiant-sounding hybrid pre with a low output impedance

hr

Bogolu Haranath's picture

Since HR mentions about hooking up the amplifier's speaker outputs directly driving the headphones, may be HR could review the RAAL SR1a ribbon headphones ($3,499), which are supplied with an amp/ribbon interface box ....... That interface box can be hooked up to an amp/integrated-amp speaker outputs :-) ........

Herb Reichert's picture

are on my head as I type this

herb

Bogolu Haranath's picture

Great ...... Eagerly waiting to read your (HR) review :-) ...........

JRT's picture

Benchmark Media AHB2 would seem to be a good amplifier for these RAAL SR1a headphones.

Bogolu Haranath's picture

Rogue Audio Sphinx (100 WPC) which HR used for comparison with this Aegir review, could also possibly be used for the RAAL review :-) ........

JRT's picture

First strike is that the Rogue Audio Sphinx lacks balanced/differential inputs with high CMR.

Second strike is that it is an integrated amplifier, which lacks flexibility in later upgrades to proper separate components with less compromised functionality.

Third strike is that they wasted resources on integrating a phono preamplifier instead of using those resources to add a couple of additional balanced inputs to connect an outboard phono preamplifier (and providing ability to later upgrade to a better phono preamplifier) located near the turntable, and to provide a tape loop with balanced I/O for recording the output of the phono preamp with a high quality outboard AD converter.

Bogolu Haranath's picture

HR usually reviews with several different amplifiers ......... Let us wait and see what HR says in his review of the RAAL headphones :-) ........

JRT's picture

I too am looking forward to reading your opinion on the RAAL SR1A.

My AKG K 1000 headspeakers also require a power amplifier suitable for driving loudspeakers, though mostly for the larger voltage swing. Those are 120_Ohm, so don't draw much current, but the low power sensitivity is such that each side needs 1_Wrms to deliver 105_dB, 11_Vrms across the load, 22_Vrms for +6_dB headroom.

Two key reasons that I bought my Audeze LCD-X and LCD-XC headphones are that they sound pretty good for what they are, for their type, and are easy to drive.

Bogolu Haranath's picture

May be HR could also review the new Revel Performa F226Be speakers ($7,000/pair) and compare them to some what similarly priced Harbeth M30.2 speakers, and many other bookshelf/stand-mount speakers and floor-standing speakers in this price range :-) .........

terzinator's picture

I'm with the others who have read the review and are itching to go out and get an Aegir -- or two!

Given the Harbeths' low sensitivity, would you recommend using a pair Aegirs as monoblocks? Or fine as a stereo amp? (Not a big room, and not super loud.)

Ortofan's picture

... Parasound NewClassic 2125 v.2.
150W/ch into 8Ω, 225W/ch into 4Ω and 400W bridged mono into 8Ω or 4Ω.
https://www.parasound.com/2125-v2.php
https://www.audioadvisor.com/prodinfo.asp?number=PAC2125V2

tonykaz's picture

----- "Best attainable sound for a component of it's kind, almost without practical considerations, with the least musical compromise" -----

I can trust Mr.HR on this, I've owned Schiit since 2011.

Schiit under-rate themselves, they underpromise yet they over deliver in performance and build quality.

They STILL put the dam power switch on the dam BACK of their devices where it's nearly impossible to reach if a person has special physical limitations . I have an outboard Levitron Illuminated Power Switch to easily control my Schiits and am envious of folks that have front chassis Power Switches ( like all normal people have ) dammit!

But...

Schiits perform like Great Voices in Opera: Joan Sutherland & Pavarotti

There might be equally great gear out there.

There might be an equally great Company out there.

But they're rare.

PS Audio comes to mind.

I keep reading Stereophile for another Outstanding Discovery like this one that our Tyll & Steve G gave to me at RMAF 2011.

Tony in Venice

ps. I'm suggesting that our Mr.HR is a Class A Recommended Audio Writer & Philosopher

Jim Austin's picture

>>ps. I'm suggesting that our Mr.HR is a Class A Recommended Audio Writer & Philosopher

I agree. Good observation.

Jim Austin, Editor
Stereophile

tonykaz's picture

I was holding back a wee bit.

This issue has 5 outstanding pieces including two from HR, the AWSi, the Barton/ John Atkinson piece, and the Cary story.

I don't read or comment on any of the Phono pieces.

Back in the Day, early 1980s, I imported and sold British HiFiN&RR Subscriptions to our American Customer Base. I did this because it was the finest Audio Mag. ( I thought ). HP was somewhat inspired writing so I sold TAS as well. I advertised in Audio Mag. Writing, back then, was somewhat useful but lacking insight.

Since around 2011 when I returned to paying attention to Published Audio, Tyll, Steve G and Bob Katz and all things digital it became obvious that no Company ( like our IVOR at LINN ) had any sort of grip on Audio Press leaving JA a hand to encourage un-hindered brilliance which showed up in the form of Tyll Hersten ( and his pals ). Phew!!!

Now, look at all the greatness migrating to Stereophile for a few thousand words ( beautiful voices in a World of Corporate Censorship ). I look around and don't quite find much interesting reading in concentrations like is flowing out of Stereophile today.

Stereophile has become the finest Audio Publication in my memory.

Nice work Mr.Jim Austin

Tony in Venice

ps. I pass-on my Stereophile Magazines to my new One Barber, barber Shop where they end up getting seen by a hundred "heads" per week, it's probably the most well-read Magazine in Venice.

Bogolu Haranath's picture

Jim Austin is the perfect person to review the relatively new JBL Synthesis S4700 floor-standing speakers ($15,000/pair) :-) ..........

Ortofan's picture

... Pavarotti, then I'll wait for one that sounds like Carlo Bergonzi.

Bogolu Haranath's picture

That one got to be the D'Agostino Relentless mono-blocks :-) .........

tonykaz's picture

Why only one?

or

are you one of those Mono people ?

tony in venice

Bogolu Haranath's picture

I said 'mono-blocks' ...... that is two for stereo :-) ..........

tonykaz's picture

Yea, you did, you're right, : BLOCKS not block !!!

I was just being silly

I didn't give this it's proper deserving thought.

Besides, those big Amps come in boxes that cost more than the Amplifier contained, making them Show-off Status & Ego type products.

They are great Amps but are they an improvement over a 1985 vintage Threshold Amp?

Tony in Venice

ps. Mr.D'Augustino is the Jeweler of Audio Gear

ps. the little Schiit Amp could be dressed up a bit by a Fab Shop doing Show Display Products.

tonykaz's picture

No Problem,

you can find his Voice by changing Tubes in your Valhalla 2 Preamp.

Tony in Venice

ps. might help to have access to a bit of wacky tobaccy .

Bogolu Haranath's picture

You mean 'wacky tobacky'? :-) .........

dial's picture

The Parasound is only 600 $ but no XLR. In the future, everything'll be class D. In France, they have the 3 D LABS NANO AMPLIFIER, 250 W per channel, also bridgeable, but 1630$. Not so many D Amps. It's a power amp too.
I don't like integrated amps (like JRT) : a lot of people don't use phono anymore (sad but true) but if they want they surely buy a separate RIAA preamp, from 20 to 20 000$. The sound can only be better than the phono boards in the pres sections. I've listened to an Atoll with phono and with their phono box, the box was way better, although it's the same circuitry.

jeffhenning's picture

...the preferred amp for the Raal headphones by their designer. Read about that here:

https://6moons.com/audioreview_articles/raalrequisite/

https://6moons.com/audioreview_articles/benchmark/

jeffhenning's picture

...it would be fantastic if the made a simple 100 watt mono block. Not a stereo that bridges to mono.

In their line up, they have this model and another that is a stereo model that bridges to 400 watts. Neither really hits that sweet spot for my system since I have a pair of Rythmik servo subs that handle everything below 150Hz. I just don't need more than 100 watts for KEF LS50's across the front

I could use this amp quite well, but it's a gigantic power hog that can help heat a small room. Schiit makes no bones about this thing running hot at idle. It pulls up to 450 watts from the wall socket. Its efficiency is incredibly low. For my purposes, this won't do.

I'm looking for a mono block to power my center speaker and not waste a ton of energy or have 400% more power than necessary.

I noticed that a few companies in Europe now offer custom nCore and Purifi mono blocks for very reasonable prices.

I guess that's my route for a center channel amp.

Bogolu Haranath's picture

Check out the PS Audio Stellar stereo or mono-blocks (Stereophile Class-A) or the Mytek Brooklyn Class-D amps (reviewed by Stereophile) :-) ..........

Ortofan's picture

... what is your objection to a two-channel amp running in bridged-mono mode?

jeffhenning's picture

Nothing wrong with a bridged mono block if you need 300 or 400 watts. Or wrong with it period.

I need around 100 watts to drive a KEF LS50 center channel. I could use a 400 bridged mode amp, but I'd be wasting money on the amp and money on the electricity to run it.

The LS50's can't really play any louder than 105dB (20dB louder than their 85dB@1 watt specification).

Again, this is for a center channel in a theater set up with two 12" servo subs (soon to be four subs).

Bogolu Haranath's picture

Why not try a low power output home theater receiver? ........ Several companies sell such receivers, which cost less than $1,000 :-) ........

Bogolu Haranath's picture

Denon HEOS AVR ($599) receiver is one such example :-) ........

Ortofan's picture

... has a 200W output rating and is priced at $399.
https://www.outlawaudio.com/products/2200.html

bikerider1001's picture

How did you do it?

Travis's picture

like to know.

Herb Reichert's picture

in greater detail how to connect headphones to power amplifiers in my next Gramophone Dream were I discuss Grado's flagship headphone: the GS3000e and the Feliks Euphoria headphone amp.

the short version is you need a set of 4-pin XLR to banana cables.

Plus you got to stay cool, pray for grace, and turn the volume up s l o w l y.
thank you for reading my stories
stay tuned,
herb

Bogolu Haranath's picture

May be HR could review the relatively new Denon HEOS Class-D, Wi-Fi and Bluetooth capable integrated amp ($499)? :-) .........

Travis's picture

Love you and love your write ups.

Still can't find those volume pots on that Schiit power amp. I look forward to your next column, especially since I am a Grado fan man.

Bogolu Haranath's picture

May be HR could also review the Manley The Absolute Headphone Amplifier ($4,500)? :-) ..........

joemariano's picture

As always, a really nice review from Herb!!!!! He always makes me want to buy more equipment. I too own Harbeths! :D And good to see Stereophile covering product that us mortals can afford. Schiit is such a rebellious company.

Talking of rebellious, I’m curious to learn what new editor Jim Austin thinks about Stereophile’s sister site Inner-Fidelity using a Schiit employee to do “reviews” and “Canjam reports”?

tnargs's picture

....you should have let go along with Joe Roberts. You peaked early with Casual Reactions, which was entertaining in its day.

But these days, most well-informed audiophiles don't fall for the spiel that amps have all these magical properties (other than hypnotically induced by the sales pitch coming from salesmen and reviewers), nor generic sonic attributes based on classification. Stuff like "spaces sound electronic" and "trippy and realistic".... let's hope that most readers aren't buying it. Not anymore.

And remind me never to reference anything you ever write about the technical side. Poor Bob Cordell, champion of Class AB MOSFET amps, finding himself referenced in a review of an essentially Class A BJT amplifier (with 3 dB of class B headroom and a "secret squirrel circuit" probably error correction applied to flatten the transconductance curve). My informed guess is that Cordell would probably argue that the topology, component choices and circuit gimmicks of the Aegir are completely unnecessary and have more negatives than positives.

cheers

georgehifi's picture

Great "little" amp, but why didn't Schiit make both this Aegir and the Vidar the exact same gains.
So that on bigger bi-amp'able speakers the Aegir could be used where it's best on the mids and highs and the Vidar on the bass, without any need for a gain matching passive volume control involved??

Shiit!!! bring out a MkII Aegir before it's too late with the same gain as the Vidar, and if mkI Aegir customers want, re-call the original to change the gain for a small fee???

Cheers George

jma78's picture

I bought the Aegir based on reviews, together with Freya + . They sound great. However, the Aegir has a 60hz like humming noise from the unit as well as going to the speakers. I tried only connecting the power cord to it (no interconnect, no speaker cables, etc), it still has the humming noise from the unit. Went through psAudio's page for getting rid of humming noise, it does not work for me. https://www.psaudio.com/ps_how/how-to-find-and-fix-hum/
I guess it's due to the quality of the transformer. The sound is not too loud, and might not bother much. But still, I decided to return them.

I hope they can provide better quality transformers and add cost to the price.

It does not feel right as they say the transformer is made in California, and yet the quality is inferior than transformers made elsewhere.

Other observations
- Aegir back panel has too little space to work with. I hope plugs are spaced further apart.
- Freya + runs very very hot, the panel is almost untouchable, and the hottest area is above the transformer, not around the tubes. It's hotter than the Aegir.
- The Freya + has a 128 step stepped attenuator. When using remote or turn manually, it seems has 3 clicks sound every time. I wonder if it goes 3 steps a time or just the sound, or it's just hard to make it one step / one click.

Update 1:
A day later, when I hook them up for last listening before sending them back. The right channel of Aegir is dead. Right channel SE plug had contact issue when I first setup them up, I had to push the plug in harder to make it work. I will not buy their product until I hear some news on quality improvement.

I also contact the brand about the issue I encounter besides a different email of return request. They responded with a return auth code but no other information. Now I got two emails from them for return auth code.

Schiit sounds like a really bad brand name when I have trouble with the product. Not funny.

JRT's picture

"Schiit sounds like a really bad brand name when I have trouble with the product. Not funny."

That seemed quotable, and maybe a little more funny if not the one suffering the trouble with the Schiit product.

georgehifi's picture

If it's physical noise from the actual amp, then that's an issue if too loud for you, Class-A amp do stress the transformers a little and they will hum sometimes, but if it's quite and you have to put your ear to it don't worry, big Krells do it too.

If the hum is from the speakers you could have an "earth loop" I believe only one piece of equipment should be earthed in the chain (with me it's the amp/s), and everything else feeds off that via all the interconnects. You could use earth cheater plugs and "leave one piece earthed" always.

https://images-na.ssl-images-amazon.com/images/I/81n1JAlgfvL._AC_SL1500_.jpg

Cheers George

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