Review and Measurements of Dayton Audio APA 150 Amp

[miero]

Audiosource A100 is an AB that measures well for $120.

I found measurements of that A100:
- https://www.kenrockwell.com/audio/audiosource/amp-100.htm#measurements

Not bad, but a quite far from good IMO.

 

[Jimster480]

When will we find the top tier budget amp?

 

[NTomokawa]

When will we find the top tier budget amp?

Patience, young Padawan...

 

[CerealKiller]

Emotiva once sold a version of the Dayton APA-150, but it's not clear to me that they share a
I'd love to see measurements of the A-100. However, it's my daily driver and I can't bear to part with it... selfish, I know!

(Also, I have the older revision without the headphone jack, and the world would probably prefer a measurement of the newer version... I'm sure there's a lot of interest in seeing measurements of that headphone amp)

Subjectively, the A-100 beats the pants off of my embarassingly large collection of class D amps like the Topping TP60 and even cheaper models from SMSL and Topping.

Please do sacrifice yourself and send that emotiva A-100 to Amir for the love of sience.

 

[JohnBooty]

Please do sacrifice yourself and send that emotiva A-100 to Amir for the love of sience.

Aside from my selfishness... I have the previous version. I think they're the same except for the lack of a headphone jack on mine. But, measurements of mine might not apply to the model you can actually buy today.

I wouldn't really have any reason to doubt Emotiva's claimed measurements of "50 watts / channel RMS; 8 Ohms; 20 Hz – 20 kHz; <0.05% THD". I mean, I don't blindly accept manufacturer specs but as far as I know Emotiva's a pretty straight shooter with this stuff.

Of course, it would also be cool to see how the amp measures at <1W and <10W.

 

[CerealKiller]

Aside from my selfishness... I have the previous version. I think they're the same except for the lack of a headphone jack on mine. But, measurements of mine might not apply to the model you can actually buy today.

I wouldn't really have any reason to doubt Emotiva's claimed measurements of "50 watts / channel RMS; 8 Ohms; 20 Hz – 20 kHz; <0.05% THD". I mean, I don't blindly accept manufacturer specs but as far as I know Emotiva's a pretty straight shooter with this stuff.

Of course, it would also be cool to see how the amp measures at <1W and <10W.

I recall having read somewhere thtat the jackless mini x and the newer A-100 are internally the same as far as circuitry goes, so there is a fare amount of chance that both measure the same. Regardless, an interesting test might be to atenuate input signal with a variable output dac and see how it measures outputing 1 to 3-4 watts, thats the kind of power some very dificult to drive plannars (argons cof cof) might withdraw, and atenuating might be necesary in order to be able to control the volumen past the imbalance zone

 

[arboleda]

I picked up one of these, open-box, for around $100. Shipping and tax bumped it up a bit. I needed something to hold me over until I can make up my mind on a reasonably high-end amp.

 

[JohnBooty]

I picked up one of these, open-box, for around $100. Shipping and tax bumped it up a bit. I needed something to hold me over until I can make up my mind on a reasonably high-end amp.

The Emotiva or the Dayton APA-150?

$100 for an open-box Emotiva is pretty nice.

 

[arboleda]

Oh sorry I meant apa-150

 

[Precautious D]

I'm considering adding a diy horn loaded subwoofer to my system and was wondering if the Dayton APA-150 could be a possible candidate for a subwoofer amp? I see it's got a low pass filter, any idea if it would suffice or would be any good in this application? The subwoofer would be a Tuba HT of variant thereof. Thanks for any input!

 

[rvsixer]

...I was wondering if the Dayton APA-150 could be a possible candidate for a subwoofer amp?

From the product's webpage "...makes the APA150 a great subwoofer amp!" .

Serious, I have two being used to drive DIY 8" subs without issue. They would drive a Tuba HT to very loud levels. I would much more worry about the number of subs and their proper placement, hint use at least two smaller subs instead of one big overkill sub but that's a topic for another thread.

 

[Precautious D]

Thanks for replying. I do intend on eventually using two subs, probably no more as I never intend on watching movies in here. I had seen the above mentioned product's website claim of being a great subwoofer amp. I was wondering if, after having been measured, anyone had opinions on whether or not it'd be good as such?

Having said all of that, bear with me, would one APA150 suffice for two subwoofers?

 

[2000drz400e]

Hi All, first post on the forum. New to the hobby as well.

I just purchased one of these from PartsExpress, unfortunately. Did anybody else find an unbearably high noise floor? With the amp just lightly above idle, playing quiet music while I do work on my computer, I can hear an ungodly crackle, hiss, and hum coming from my speakers. It increases and decreases when I run the volume up or down on the amp. I have been just leaving my amps about 1/3 of the way up and adjusting the volume with my computer. Before, I had a cheapo Fosi Audio 50+50 I got on Amazon.

I wanted to have some more power and the promised .01%THD at full power this amp's specs promised for when I build the Paul Carmody Amigas in a few weeks. Wish I saw this review first and I would probably have passed. Based on the graphs it doesn't seem much better than the TPA3116's spec sheet, which is the chip that's in the Fosi 50+50. It struck me as odd that I could pay 3 times the price of the Fosi and get something that seems to be worse. The Fosi is utterly silent and produces no heat as far as I can tell. To my ear and with my gear, they sound pretty similar. Playing 320kbps tracks off a mid range Asus integrated sound card through Parts-Express C-note speakers.

 

[deb1shis]

This is a review and detailed measurements of the Dayton Audio APA 150 power (speaker) amplifier. It is on kind loan from a member. It costs USD $168 from Parts Express including free shipping. If the specs of 75 watts/channel are true, you are getting a stereo amplifier for about $1 per watt! Amazing how cheap these amplifiers have gotten.

The APA 150 is a chunky unit, departing from the typical wide cabinet format:

View attachment 21359​

As you see, there is a volume control so you can skip a preamplifier if all you have is one input. In the back, there are switches for bridging to mono, filtering and auto on.

The unit is fan cooled but it is temperature controlled and quiet.

The design is the classic class AB with a linear power supply which makes the unit heavy and inefficient. So good to see the fan there to keep things cool.

There are serious looking ETL/CE safety and regulatory markings on the unit which I take to be genuine and provide peace of mind.

Let's get into measurements and see how the APA 150 performs.

Measurements
Let's start with our dashboard view while the input is adjusted to produce 5 watts into both channels:

View attachment 21360

We get typical performance of budget amplifiers. SINAD (signal over distortion and noise) is in the 70s with lots of harmonic distortion and power supply noise apparent. No awards will be won at this rate.

Channel mismatch as far as distortion is fairly large which shows up in warm-up sequence just the same:
View attachment 21361

Stability is really good though so you don't need to leave the unit on. It is as good or bad as when it first turns on.

As noted the fan was on during this test and blew a lot of air that was barely warm.

Frequency response is very good and typical of class AB amplifiers (which don't need filtering as switching amplifiers do):
View attachment 21362

Response is down just half a dB at 40 kHz limit of the test.

Likewise output impedance is negligible:

View attachment 21363

Impedance is 1 ohm or less at 20 Hz and averages 0.4 ohm above that. In other words, there will be no trouble running any impedance speaker with respect to impacting its frequency response.

Let's look at all important power versus distortion measurement:
View attachment 21364

Compared to our previous budget amplifiers, the Dayton Audio APA 150 beats them slightly on power, producing nearly 90 watts into 4 ohms. And it does that with lower distortion to boot.

Distortion+noise versus frequency at a few power levels is ugly though:
View attachment 21365

At 50 millivolts of input, the graph is dominated by noise especially in high frequencies (red). As we increase the input levels, we get two clusters of lines, one for good channel and not so good channel. All show much increased distortion with frequency, rising to as much as 0.1%. Between 2 and 5 Khz where our hearing is most sensitive, we are looking at 0.02 to 0.03% or about 50 times worse than most DACs.

Conclusions
The Dayton Audio APA 150 performs along the lines that we have sunk into in budget amplifiers. Lot of cheap power with cringe-worthy distortions and noise. Fortunately when it comes to non-linear distortions, our hearing is fairly poor so likely people are satisfied with the great value they are getting.

I like the fact that the APA 150 is safety rated given the high voltages and currents running around in power amplifiers. The fan with its high air flow gives me comfort that it will run cool and likely reliable even under max load.

No doubt with good speakers and content, the APA 150 will provide an enjoyable experience. But if you are after the best as I am, this is not it. Our hunt for reasonably priced amplifier but with high performance continues....

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Hi Amir,

I am an audio crazy person and listen to AOR only. Please let me know your recommendations (the ones you would have liked the most had there not been any budget constraints) of (i) Speakers, both bookshelf and floor-standing, (ii) Power amp - Pre amp or Integrated amp and (iii) DAC (By the way, I cannot afford DCS Bartok).

My primary set up consists of Paradigm floor-standers (Monitor series v6), Concept 16.5 Integrated amplifier, ASUS Xonar Essence One DAC and the source is CDs ripped in WAV format. I have two rather conflicting likes viz.
1. I like amps with high damping factor but at the same time
2. like the open sound of Wharfedale W40 speakers very much.

My secondary system consists of Klipsch RF35 floor-standers, NAD 326 BEE amplifier and ASUS Xonar STX II sound card. I am also looking for an appropriate Pre amp for Krell KAV 250a, the sound of which seems to me to be suppressed, closed or narrow (don't know how to describe it).

Thank you.

 

[JSHamlet234]

Hi All, first post on the forum. New to the hobby as well.

I just purchased one of these from PartsExpress, unfortunately. Did anybody else find an unbearably high noise floor? With the amp just lightly above idle, playing quiet music while I do work on my computer, I can hear an ungodly crackle, hiss, and hum coming from my speakers. It increases and decreases when I run the volume up or down on the amp. I have been just leaving my amps about 1/3 of the way up and adjusting the volume with my computer. Before, I had a cheapo Fosi Audio 50+50 I got on Amazon.

I wanted to have some more power and the promised .01%THD at full power this amp's specs promised for when I build the Paul Carmody Amigas in a few weeks. Wish I saw this review first and I would probably have passed. Based on the graphs it doesn't seem much better than the TPA3116's spec sheet, which is the chip that's in the Fosi 50+50. It struck me as odd that I could pay 3 times the price of the Fosi and get something that seems to be worse. The Fosi is utterly silent and produces no heat as far as I can tell. To my ear and with my gear, they sound pretty similar. Playing 320kbps tracks off a mid range Asus integrated sound card through Parts-Express C-note speakers.

Just saw this older post and thought I would share since I had the exact same problem with a similar setup.

ASUS X99-A motherboard (ALC1150) -> Dayton APA-150 -> Velodyne CT-120 sub (80Hz high-pass on speaker-level in/out) -> Paradigm Mini Monitor V3 bookshelf speakers.

The problem was a ground loop. Unlike any of my other integrated amps and AVR's, the Dayton APA-150 has a safety ground. Since my desktop computer has one too, I was getting audible noise all the time, and a somewhat loud buzz any time my graphics cards were in use.

To test this, I swapped the power cord for one that does not have a safety ground and the problem disappeared. This amp is now dead quiet, even with the gain at maximum. It's better than some of my supposedly better equipment in that regard. There are better (safer) ways to eliminate ground loops, and I recommend researching them yourself as I am no expert.

 

[Deleted member 9685]

I'm not an audiophile. I just want a baseline of audio performance.

While I'm reasonably satisfied with a chinese generic TPA3251/TPA3255 amplifier, I discovered that class D amps emit electromagnetic radiation in AM radio frequencies. I'm trying to minimize electromagnetic radiation from pulse width modulation of class D amps and dirty electricity from switch mode power supply. Dirty electricity in house wires is converted to electromagnetic radiation in frequencies that a portable AM radio can pick up.

If Dayton APA150 is actually an affordable class AB amp with a linear power supply, this would emit far less electromagnetic radiation and inject far less dirty electricity into my house wiring. The linear power supply of Dayton APA150 may not be ideally linear, but I think it should still be better than switch mode power supplies.

I think I'm going to replace my cheap chinese class D amps with Dayton APA150.

 

[JohnnyN]

BlackLion, did this wind up being a noticeable upgrade for you?

 

[Deleted member 9685]

BlackLion, did this wind up being a noticeable upgrade for you?

@JohnnyN I'm not watching this thread, and you didn't mention my user name with @. Thus, I was not notified of your post.

I am considering LOXJIE A30 at this moment.

 

[swampfire]

I decided to order one of these, though I thought it was odd that they don’t give the power rating for 8 ohms stereo. This will drive the speakers in my arcade and back patio, definitely not critical listening situations. I love the form factor for my network closet rack, but the killer feature is the 5 year warranty. I’ll report back with my impressions in a week or so.

The current Parts Express price is $232 with tax.

 

[IPunchCholla]

Just saw this older post and thought I would share since I had the exact same problem with a similar setup.

ASUS X99-A motherboard (ALC1150) -> Dayton APA-150 -> Velodyne CT-120 sub (80Hz high-pass on speaker-level in/out) -> Paradigm Mini Monitor V3 bookshelf speakers.

The problem was a ground loop. Unlike any of my other integrated amps and AVR's, the Dayton APA-150 has a safety ground. Since my desktop computer has one too, I was getting audible noise all the time, and a somewhat loud buzz any time my graphics cards were in use.

To test this, I swapped the power cord for one that does not have a safety ground and the problem disappeared. This amp is now dead quiet, even with the gain at maximum. It's better than some of my supposedly better equipment in that regard. There are better (safer) ways to eliminate ground loops, and I recommend researching them yourself as I am no expert.

Just wanted to second this as I had the exact same experience, ground loop solved by one of those three prong to two prong adapters. I still need to look into a better long term solution.