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: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: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.As usual we start with our dashboard feeding a 1 kHz tone into the amp, aiming for 5 watt output into 4 ohm: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: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:Signal to noise ratio is good, matching what we need for 16 bit audio playback:Multitone test tells us intermodulation between 32 tones fed to the amplifier: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 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: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: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: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: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: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.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.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. Pleaseusing: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/