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Review and Measurements of Schiit Aegir PWR Amplifier

amirm

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#1
This is a review and measurements of the Schiit Aegir stereo Power (speaker) amplifier. It is on kind loan from a member who has been patiently waiting since August for its review! The Aegir is sold direct by Schiit and costs US $799 plus shipping.

The Aegir is very heavy, substantial and serious looking piece of audio gear in black:

Schiit Aegir Stereo Power Amplifier Audio Review.jpg

What I don't like is the extra sharp edges of the heatsinks on each side where you naturally want to grab it. But I understand extruded aluminum comes this way and having the corners marchined would be expensive.

Here is the back panel:

Schiit Aegir Stereo Power Amplifier Back Panel Connectors Audio Review.jpg

At first I was super excited to see the XLR input but became puzzled why a stereo amp only has one of them. Then I realized that it is only for driving the unit in bridged mode. So for most of my testing I used RCA and then used XLR for bridged power testing.

I can't quite tell what type of amplifier this is from technical terms Schiit uses. They seem to want to say this is mostly a class A amplifier but then it isn't at higher power? Anyway, the Aegir runs warm but not too hot so whatever trick they are using to lower power consumption of this unit versus pure class A is working.

The Aegir is a new design which was introduced in 2018. I see Audio Precision measurements for it which means it is part of the new design philosophy to take measurements and design verification seriously.

Amplifier Audio Measurements
As usual we start with our dashboard feeding a 1 kHz tone into the amp, aiming for 5 watt output into 4 ohm:

Schiit Aegir Stereo Power Amplifier Audio Measurements.png


Starting on the left side, the gain of 20 dB is on the low side. Then again the output power is so low (see later) that you don't need a lot of gain to get to maximum power.

SINAD (signal over noise and distortion) which is a positive dB version of THD+N mathematically (here anyway), puts the Aegir in respectable, above average ranking of all power amplifiers tested:

Best stereo amplifiers tested.png


We see good bit of power supply spikes which I verified to also exist in Schiit AP measurements. Levels are below -100 dB so likely not audible due to our poor sensitivity in low frequencies.

Frequency response is ruler flat in audible band:

Schiit Aegir Stereo Power Amplifier Frequency Response Audio Measurements.png


Signal to noise ratio is good, matching what we need for 16 bit audio playback:

Schiit Aegir Stereo Power Amplifier SNR Audio Measurements.png


Multitone test tells us intermodulation between 32 tones fed to the amplifier:
Schiit Aegir Stereo Power Amplifier Multitone Audio Measurements.png


Once again, we see that we clear the 16 bit threshold of CD music.

Most important test is power versus THD+N. Let's see that for 8 ohm:

Schiit Aegir Stereo Power Amplifier Power into 8 ohm Audio Measurements.png


Schiit rates this amp at 20 watts into 4 ohm so we are close. Likely they allow 1% distortion versus my standard of onset of clipping.

What is puzzling is 4 ohm output:

Schiit Aegir Stereo Power Amplifier Power into 4 ohm Audio Measurements.png


We are long ways away from 40 watts. Then again, the clipping tilts to the right some so I suppose if you walked up that curve far enough, you get to 40 watts. You would get good bit of distortion though so 40 watts is a marketing number.

Note that one channel is more unhappy than the other. I confirmed that exists just as well in Schiit measurements. So likely power is fed is less efficiently to one amp than the other. Or there are grounding, component mismatch, etc..

To test bridged mode, I fed the Aegir vial XLR balanced connection and got this:

Schiit Aegir Stereo Power Amplifier Power into 4 ohm Bridged Audio Measurements.png


I only get 23 watts of usable power which is hardly more than 19.5 watts I got in stereo mode. The curve tilts to the right more now so marketing department went to town there to spec the "80 watt number."

Measuring dynamic power which uses 1% number Schiit uses, we do get much more power:
Schiit Aegir Stereo Power Amplifier Peak Power Audio Measurements.png


So with real music, you likely have more power than my continuous tone tests indicate.

Let's test how sensitive the Aegir is to input frequency:

Schiit Aegir Stereo Power Amplifier Power vs Distortion vs Frequency Audio Measurements.png


Sort of a classic output in that lower frequencies limit the amount of power available (clips earlier) but also have lower distortion.

I was asked to add multitone test to my amplifier measurements. I usually use that for DACs since there, it is a lossless signal. To use it for amplifiers, the signal has to be converted from PCM to analog which invokes the DAC in the AP. That would put a limit on how good of a measurement I can make. For amps like Aegir is not a limitation though so here it is:
Schiit Aegir Stereo Power Amplifier Multitone Audio Measurements.png


We see the general distortion floor is around -100 bits or 17 bits. However, there are some earlier spikes due to power supply noise. Again, our hearing is not very sensitive in that region so they can be ignored.

Conclusions
The Schiit Aegir is a competently designed amplifier with solid build quality and no design mistakes. It shows the power of proper measurements and engineering verification to remove the element of surprise in third-party verification job we perform here.

The main issue here is lack of power. To someone like me, with very large spaces, rather inefficient speakers and desire for bass that you feel as much as you here, the Aegir is definitely not for me. Nor do I buy into "Class A" having any benefit. If it had, it would show up in measurements. It does not.

If have efficient speakers and/or don't listen very loud, the Aegir is a solid offering from a western company. I am going to put the Schiit Aegir on my recommended list for its solid engineering and design. Fitness for application is up to you!

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

It is getting cold here and they say winter will bring more snow than usual. So I need to go outside and chop some wood. Being busy doing reviews means I don't have the time so I need to buy some instead. Please donate using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

amirm

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#2
And oh, I set up a nasty contraption to take the shots you see in this review. My wife has not seen it yet but I am sure once she does, you can add being homeless to the list of reasons I need money from you all! Hope you are happy pushing me in this direction!!!
 

DonH56

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Something seems amiss with the bridged results. I am wondering if the XLR was wired rightly or if there is another switch or something needing throwing. Rarely do amps achieve the ideal 4x power but most manage to at least double or so the non-bridged result...

As for being homeless, and whilst happy to contribute, don't you have a camper? Without the wife, more room for test gear, not seeing the problem? :D
 

Noob

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#4
This is nice to see. It's a shame about the power limitations, but for low power on a desktop, this could be great.
 

617

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#7
The product shots look excellent Amir. I don't think they're strictly necessary but you seem to enjoy including them so I wouldn't complain.

I think it's worthwhile to mention that high sensitivity speakers are pretty uncommon. If using dynamic drivers, and assuming you want bass into 40hz and a reasonable size, it's pretty unusual to see designs reaching 90db/2.8V. 86db is respectable/normal for bigger speakers, 83db is not uncommon for small speakers trying to get big bass. Anything above 93db is esoteric in some way - pro sound drivers, big size, horns and line arrays.

BW 802D: 89 db
LS 3/5a : 83db
LS50: 84 db
Dunlavy SC IV : 92db (and six feet tall)
JBL Synthesis 1400 : 89db

A big spread of speaker designs and sizes, all within 9db sensitivity.
 

Matias

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#8
White background is nicer indeed.
 

DonH56

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#11
A fair number of entry level and HT speakers are in the 90-100 dB/W/m range, with some horns claiming >100 dB/W/m. Many smaller ("bookshelf") speakers are on the low side (partly) because the tweeter is padded down (attenuated) to better match the woofer and extend the LF corner.
 

Cahudson42

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#12
Nice review thoroughness, as always... More power/headphone/integrated/AVR amp reviews like this! Pause the DACs for a bit..:)
 

amirm

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#13
Something seems amiss with the bridged results. I am wondering if the XLR was wired rightly or if there is another switch or something needing throwing. Rarely do amps achieve the ideal 4x power but most manage to at least double or so the non-bridged result...
It has the same issue with 4 ohm hardly providing any power. I think it has some current delivery issues.

I wired the unit as instructed which is to use both positive terminals and XLR input. There are no switches.

I think they are using very high distortion levels to measure 4 ohm and bridged power. If you see the curve tilts to the right so you can keep climbing it and claim larger and larger power numbers.

Here are the only two graphs like mine from Schiit Measurements:

1570558393779.png



1570558557630.png


As you see, it just doesn't output much power unless you read way past the clipping point.
 

617

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#15
A fair number of entry level and HT speakers are in the 90-100 dB/W/m range, with some horns claiming >100 dB/W/m. Many smaller ("bookshelf") speakers are on the low side (partly) because the tweeter is padded down (attenuated) to better match the woofer and extend the LF corner.

I'm not familiar with theater sound products.
What speaker does 100db/w with bass down to at least 60 hz? And yes, hf transducers are almost always more efficient than LF. Passively attenuating lf drivers is generally not a good idea.

My point, as it is relevant to this amplifier, is that a 15w amp isn't that useful, and most contemporary speaker design is done with the assumption that users have unlimited amp power at their disposal. I'm not sure if that's a good thing but it's how things are.
 

DonH56

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#16
It has the same issue with 4 ohm hardly providing any power. I think it has some current delivery issues.

I wired the unit as instructed which is to use both positive terminals and XLR input. There are no switches.

I think they are using very high distortion levels to measure 4 ohm and bridged power. If you see the curve tilts to the right so you can keep climbing it and claim larger and larger power numbers.

Here are the only two graphs like mine from Schiit Measurements:

View attachment 35473


View attachment 35474

As you see, it just doesn't output much power unless you read way past the clipping point.
Ah, makes sense, I read too quickly. If they are current limited then sure but why bridge at all? I wonder what they used to derive that 80 W number? Burst tones? Or maybe it is just defective...
 

Fred Jacquot

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#17
Bridging doubles voltage capability, not current. And each amplifier sees the load divided by two. At 4 ohms, amplifiers are usually already limited by current. To me, it makes sense that power somehow stays the same. Maybe testing bridged mode at 8 ohms would be more representative from real usage.
 

DonH56

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#18
I'm not familiar with theater sound products.
What speaker does 100db/w with bass down to at least 60 hz? And yes, hf transducers are almost always more efficient than LF. Passively attenuating lf drivers is generally not a good idea.

My point, as it is relevant to this amplifier, is that a 15w amp isn't that useful, and most contemporary speaker design is done with the assumption that users have unlimited amp power at their disposal. I'm not sure if that's a good thing but it's how things are.
Not something I have spent any time looking at but bigger horns and horn-loaded speakers will do it; but I did not think your original post mentioned a LF corner (I probably just missed it, sorry). Low-power audio is not an area I follow (not with my speakers!) but there seems to be a gob of folk chasing the SET sound and very low-power amps these days. I just read about a big horn system claiming 105 dB/W/m sensitivity but I don't know which one -- it had great big red horns and just was not something I would buy so I wasn't really paying attention.
 

DonH56

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#19
Bridging doubles voltage capability, not current. And each amplifier sees the load divided by two. At 4 ohms, amplifiers are usually already limited by current. To me, it makes sense that power somehow stays the same. Maybe testing bridged mode at 8 ohms would be more representative from real usage.
Most amps double the minimum load spec when bridged so using an 8-ohm load in bridged mode does make sense. Maybe there is some current-limiter someplace?
 

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