Review and Measurements of Schiit Aegir PWR Amplifier

[Willem]

See here for the AS700, the AS701's predecessor without the digital inputs: https://www.avhub.com.au/product-re...grated-amplifier-review-and-test-page3-393552 And here for a test of the AS801, i.e. the AS701 with an additional usb input: https://www.audioholics.com/amplifier-reviews/yamaha-a-s801-amplifier-review

 

[AudioSceptic]

I repaired one of those back in 1980 or so! It was totally toast and I did not have schematic for it. Took me a while to get it working.


That was what I found! I was so ready to hear class A sounding better but made no difference at all.

I remember reading reviews of those. No one could hear a difference, but then the distortion figures for A/B were already very low (for the time). IIRC they were the CA1000 and CA2000 and you didn't get the Class A option with the receivers (CR1000 and CR2000).

 

[Juhazi]

In one set I have a XTZ AP100 power amp which has A/AB switch. I cant hear a difference... But a PrimaLuna PrologueThree tube preamp gives warmth of harmonics for winter nights!

 

[AudioSceptic]

Basically, the A-S701 is a 1991 AX-570 with a single board D/A converter jammed in (on top of the main filter caps...), electronic input switching and a cosmetic makeover.

View attachment 35500

1991 AX-570:

View attachment 35501

Same ToP-Art sub chassis (a piece of plastic), symmetrical design, plenty of sliver buss links, same topology etc.

The AX-570 was a top seller nearly 30 years ago and my bet is, it will test just as well (or better) than the AS-701.

The AX-570 was tested by the The Audio Critic in issue 24 <http://www.biline.ca/audio_critic/audio_critic.htm> They thought it was pretty good.

 

[AudioSceptic]

Class A amplifiers are great in winter for heating up your listening room.

Because of inefficiency and consequent heat dissipation, if you want lots of power and Class A you need to go really big. That's what the Krells were all about.

I think the max efficiency of Class A is only 50% but that's at full output. At idle it's even worse.

 

[JohnBooty]

The reputation of Schiit is that they are better marketeers than device builders to foist some of their bad equipment on consumers. If that reputation was deserved, then they would not be putting out such statements like it will still run hotter.

Heh. I suppose that if you define marketing as "never, ever be honest about the cons of your products" then yeah, any sort of honesty about your product's weaknesses is bad marketing. That is certainly one way to market one's products, but thinking that's the only way to market is... a limited understanding of marketing. Honesty (or the appearance of honesty, if we're being cynical) is a strong marketing tactic and that's always been their brand. Example from their $99 Magni 3 FAQ, which is AFAIK largely unchanged from their Magni 1/2 marketing copy:

Q: So why would I buy any of your other amps?
A: Class A. Tubes. You like larger things. Lots of reasons, really. But we’re dead serious—this is really all you need.

 

[DonH56]

Class B has clear discontinuity as one transistor gets biased with the other one not working. That gap is compensated in class AB by pre-biasing the two transistors so that they can hand off to each other quickly. That compensation is simple and hence the reason there is no such thing as class B audio in the market.

Class A's advantage is simplicity in circuit design. When transistors were expensive and so was labor, having an amplifier with half the parts was an advantage. That has not been the case for decades. The efficiency advantage of class AB has obsoleted class A in audio for years.

Exactly. At low levels crossover (sometimes called notch) distortion is clearly audible. Adding a bit of standing current to a class B amplifier, biasing into AB, essentially eliminates that low-level distortion. Where most of us, or maybe just me, have issues is when "pure class A" or some such is pushed as superior for a higher-powered amplifier. Aside from the wasted energy, heat, lower output power, and cost, by and large the class A amplifiers I have heard and measured through the years (with a few exceptions) have exhibited worse performance than class AB designs. HIgher noise and distortion, lower stability (tolerance to nasty speaker loads), more bias drift, etc. There are examples of great class A designs with none of those issues, but my room gets hot enough in the summer as it is, my electric bill is high enough, and I need more power than is really practical in a pure class A design at least at the cost (dollars and heat) I am willing to spend.

Edit: The theoretical peak efficiency of a push-pull class A design is 50%; single-ended outputs drop it down to ~27%. Add low-level stages and such and you drop even lower.

 

[peng]

That Yamaha AS701 measures far better than the AVRs tested here. I have posted links in the past.

That's interesting, and would seem defy logic, would you mind posting the link again, please..
I have seen some measurements on the A-S801, it's good but not that great, relative to some AVRs measured by AH.
https://www.audioholics.com/amplifi...1-amplifier-review/yamaha-a-s801-measurements

Edit:. Sorry somehow I missed your earlier post. Yes I read and in fact saved that review long time ago so I forgot until I saw your link. For comparison, I prefer AH's because they also measured AVRs so I can compare apple to apple (same methodology, and reviewer). Regardless, even the linked measurements did not show any "far better" result as such. I would stick with real integrated amp that don't share parts with AVRs.

 

[Aap op Sokken]

@amirm An error in the review text:

Schiit rates this amp at 20 watts into 4 ohm so we are close.

This is for 8 ohm.

 

[Frank Dernie]

Richard Heyser in his 11/86 Audio Klipschorn review stated that FR was reasonably uniform from 38Hz cutoff to 18KHz. He measured 98dB with one watt, in his room.

My Tune Audio Animas measured 109dB/watt and go down to 40Hz in my room, but they are not sold as Home Theatre speakers.

 

[maty]

Schiit Aegir

versus cheap but very good DIY class A of 20 watts at 8 Ohms.

Aksa Lender P-mos Hybrid Aleph (ALPHA) Amplifier

https://www.diyaudio.com/forums/solid-state/318102-aksa-lender-mos-hybrid-aleph-alpha-amplifier.html

Look at the graphic so clean up to the 1 kHz tone, you know, clean power. But my little coaxial is only 85 dB/W/m and not 91 dB/W/m -> I need more watts to listen to very good recordings, in far field, with DR15.

 

[Frank Dernie]

Putting a Schiit Aegir in the same sentence as an MX-600/800/1000 is not fair on the Yamahas...

No comparison:

(my scans)
View attachment 35537

Specs. I have an MX-600 here, it's an incredibly quiet amplifer (hiss). 16uV residual.

View attachment 35538

And here, just for fun, here is the matching CX-1000 preamplifier. A lesson in how to build a preamplifier in 1989. Onboard D/A converter too.

View attachment 35539

The design aesthetic unfortunately hasn't stood the test of time. Yamaha mixed jutting angles with clean lines, something they fixed in the next series, the MX-630/830 range of 1990/1. It had slightly rounded panel tops and bottoms, softer controls and a way nicer look. Trouble is, the performance took a hit.

I want...

 

[anmpr1]

My Tune Audio Animas measured 109dB/watt and go down to 40Hz in my room, but they are not sold as Home Theatre speakers.

From re-reading the Heyser review, I discovered that he made his measurements at 3.5 meters (11 1/2 feet). This would explain the discrepancy between his 98dB, and Klipsch stating that sensitivity is 105dB @ 1 watt/1meter in anechoic space.

Addendum: The reason Heyser measured at this distance was that the speaker is very large, requires a structural corner, and is intended to be used in a home environment at a listening distance of greater than 3 meters. With my La Scalas, 3 meters (9 feet) is about as close as you want to get in order to obtain a good stereo image with some bass impact. A subwoofer is helpful for acoustics below 40 Hz.

 

[Bruce Morgen]

In my book an anaemic amplifier like this is pretty useless, and all the more so when less money buys far more and better power.

Seen from my admitedly devout price-performance P.O.V., this seems to be pretty much a $79.99 woth of amplifier selling for $799, its nice appearance notwithstanding. I guess if you hear something remarkable in Class A amplification and have the bank balance it's worth considering -- but I for one would choose to put that $799 toward something like a Threshold or an amp built around top-notch Class D modules.

 

[tomchr]

I'm surprised to see that a product that doesn't meet the published specs makes it on the "recommended" list. The industry went away from specifying "music power" a long time ago for a good reason. Let's not encourage it to be brought back.

Tom

 

[dtaylo1066]

Stereophile Magazine measurements said:

"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).

Read more at https://www.stereophile.com/content...er-amplifier-measurements#5PLSd4rBP2R1uVSm.99

 

[dtaylo1066]

Good looking amp and seems well designed, they are just fudging some on the power specs a bit. Class A is typically a 15 to 30 watt kind of thing. And those who love it seem to be loyalists. I may build a First Watt F6 clone to try it out. Nice kit on the DIY audio store page. Thanks, sir, for all your work and measurements.

 

[HammerSandwich]

Figs. 4 and 5 indicate that the distortion is very low at all powers below clipping.

He meant figures 6 & 7. The 8Ω chart's solid, but the amp looks unhappy into 4Ω. "Distortion is very low" does not mean "THD freakout before reaching 50% output" in my book.

 

[tomchr]

"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.

I - like Amir - use the point where the THD starts degrading severely (i.e. "shooting up") as the point of clipping. Schiit uses 1% THD. I can see where they're coming from, but unless the amp clips softly (which the Schiit doesn't) I think it's more honest to use the point where the THD+N graph shoots up.
Also note that Stereophile tends to use quite few points in the sweep, so the difference in output power between the data point with THD below 1% and the data point with THD above 1% can be quite significant. That's another way of "cooking the books".

I'm not suggesting that one method is right and another is wrong, only that I find "my" method (which Amir also happens to use) to be more honest. Then again, my honesty will probably limit my business potential as my output numbers will always be lower than "the other guy's".

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).

That's no longer a case of reading a graph in a certain way then. That's a case of a "music power" spec. Or perhaps a made up "spec". Either way, I'm disappointed that stuff like this makes it to the "recommended" list.

Tom

 

[tomchr]

He meant figures 6 & 7. The 8Ω chart's solid, but the amp looks unhappy into 4Ω. "Distortion is very low" does not mean "THD freakout before reaching 50% output" in my book.

I agree. The amp clearly loses its mind starting at around 15 W into 4 Ω. Stuff like that wouldn't make it past the prototyping stage in my lab.

Tom