Dayton Audio A400 new AB amplifier

[delta76]

As a scientist myself I have a great deal of respect for the measurements and that's the main reason I visit this forum, but I'm not convinced that everything that matters is currently being measured.

Clearly in terms of THD and SINAD the highest quality class D is now superior to AB. If all that matters is maximizing these numbers, then there is no thinking or listening needed. Just pick the best score and be done. The designs by Hypex and Purifi in particular have made remarkable strides. I expect this technology will continue to improve over the next several years. I would rather wait a while more. For now, I feel more comfortable with class AB.

Well, not trying to change your mind but if you claim to be a scientist then there are several of researches regarding audibility of different amp classes. There are more than SINAD to consider of an amp (power, frequency dependency, impedance dependency, longevity, support, etc. ), but it is the first easy measurement to filter out bad amps. Amir for example is very tolerant of SINAD for amp and he will be happy to recommend a ~80dB SINAD amp if it also does well in other aspects with respect to price.
There is no reason to pick a low SINAD amp now given better options are available in all price ranges. And absolutely no reason to prefer class AB to D because of some prejudice. Sure you can pick a benchmark or a mcintosh because they like them for whatever reasons. But skipping class D because they might sound inferior to AB is at very least, very uninformed

 

[DVDdoug]

I visit this forum, but I'm not convinced that everything that matters is currently being measured.

It is!!!

And we (they) can measure better and more precisely than we can hear.

In reality, most amplifiers (most electronics) are better than human hearing unless there is audible background nose, or unless you overdrive it into clipping/distortion. i.e. The "N" is more important than the "D". There is more than one way to measure noise (or SINAD) and the audibility of noise depends on a lot of factors so it's not an easy thing to nail down. ALL active analog electronics generate SOME noise.

The audiophools who believe that measurements don't capture everything can't "pass" a blind ABX test and when they fail they start making excuses about why blind listening tests are invalid. ...As if making the test non-blind and non-controlled somehow makes it better.

Also see Controlled Audio Blind Listening Tests (video)

BTW - The audiophile community is dominated by nonsense. This is one of the few rational-scientific resources.

Audiophoolery discusses the actual characteristics of "sound quality".

As a scientist myself...

Just be aware that there is often some science in the nonsense. A lot of smart-educated people get sucked-in because they understand or trust the science. But it may not be applicable to the practical audio world, or they aren't taking into account the limits of human hearing. One example is that I had an oscilloscope on my bench that goes up to 100MHz. And I could build preamp that goes to 1MHz, almost without thinking. But 20kHz is good enough for human hearing.

"They" often say that the ultrasonics can affect what we hear in the audio range but that's not true unless something is wrong. And if something is wrong, the ultrasonic content can only degrade the sound.

Clearly in terms of THD and SINAD the highest quality class D is now superior to AB.

I'm not sure that's true... I have no idea what the best measuring amplifier is, or what class it is. But it ain't rocket science to make an amp that's better than human hearing and beyond that, it doesn't matter (it can't make an audible difference).

A lot of people think class-A is the best. But, it's class-A because it was first. When I was a kid in the 1960s almost everything was class A including the amplifiers in radios, TVs, car radios, etc. It required one less tube or transistor and it's just how "everything" was made. (There were class A/B hi-fi amps by that time.)

 

[MAB]

As a scientist myself I have a great deal of respect for the measurements and that's the main reason I visit this forum, but I'm not convinced that everything that matters is currently being measured.

Public service...
A long time ago, people couldn't hear the differences between amplifier classes, for example Class A vs. Class AB vs. OTL tubes. See page 78 for a classic test of these:

https://americanradiohistory.com/Archive-HiFI-Stereo/80s/HiFi-Stereo-Review-1987-01.pdf

Nothing in our hearing has changed since these tests were made. Many more people since then have failed to hear differences between amps run within their capabilities, unless one was severely defective. So the improvements in amps beyond a point are audibly meaningless.

David L. Clark and others organized many of these tests. A survey can be found here although it does require payment:

AES Convention Papers Forum » Ten years of A/B/X Testing

The AES Forum is where our members get to interact with each other in between conferences and section meetings.

secure.aes.org

The audible differences in amps is usually the frequency response, not the distortion. There needs to be quite a bit for an amp's distortion to become audible. You can demonstrate this to yourself by adding distortion to a clean signal and determining what level you can actually detect the distorted sound. You can also see how good even order HD sounds compared to odd-order, and contemplate why amps get such Or taking Klippel's listening test.

Your doubt that waveforms can be described by measurements that are not currently available goes against quite a bit of research, not just audio research. What do you have in mind?

 

[rjp]

You know what, I think I'll try one to see what I think. Is the Buckeye NCx252MP is a good place to start? 150 wpc into 8. Sounds like enough power for me, though I suppose more might be even better. I'll be driving a pair of Dynaudio Special 40s. This one is Hypex Ncorex I believe. Should I go Hypex or Purifi? I'd like to keep it under 1200.

Is this the best place to buy?

Website says 2-3 weeks build time. Is there any way to get one faster?

Buckeye Amps

Buckeye Amps utilizes the most advanced audio amplifier technologies available. Authorized seller for Hypex and Purifi Class D amplifiers. Based in the US. Free shipping and worldwide service!

www.buckeyeamp.com

Thanks

 

[delta76]

Ncx252 should be enough for 99% cases. You can move up if you have money to buy the end game amp. Both ncx500 and purifi are good, but purifi has a slight edge which is not audible anyway.
In the us yes, other is VTV. You can always drop them a message asking if it can be any faster.

 

[rjp]

Thanks. Leaning towards the NCx252MP.
I messaged Buckeye about the build time

 

[ss1976]

Hi all. The Polk R700s arrived today. As of yesterday I'm streaming from the Wiim Ultra into the Douk Audio U2 Pro then into the FIIO K11 R2R into the Onkyo RZ50 into the Dayton Audio A400. Everything sounds phenomenal to me. The FIIO definitely livened up the audio from the Wiim. It sounds less compressed. Not sure how much the Douk is contributing, haven't had time yet to a-b with and without. For kicks I also picked up an a-b box to switch between the R700s and Polk XT70s. If judging the two sets of speakers on a 1 to 10 scale, if the R700 are a 10 the xt70s are a 7. The clarity, punch, and overal sound quality is a nice step up as you'd expect. Last of all the amp. I had my decibel meter out and with my Onkyo's dial turned up to 70+ I was over 90db, louder than I would ever use them. If I'm having a party I'll pull out the JBL pa system. The amp has no problem driving the R700s. Even with the audio cranked they still sounded clear. How they would compare to similarly priced solid state amps I can't say. I don't have the experience to judge or equipment to compare. If someone wants me to compare the two feel free to loan me a Buckeye and I'll gladly give it a whirl. So for $500 the Dayton seems to have been a great choice. Also, I'm not going amp/speaker sniffing at the local audio store so currently I'm listening to best system I've ever heard and I think I'll keep it that way till I hit the lottery maybe. Good luck with whatever you choose. Hopefully it checks all the boxes. Keep us posted!

 

[ss1976]

Happy Saturday everyone! While I had the amplifier out to put some felt pads on it's feet, I decided to pop the hood. Here's a few photos of the internal components.

 

[DrPop]

Long time reader, but finally something I can possibly help out with, so my first post here.

After seeing the price drop on the Dayton A400, I pulled the trigger and gave it a try. I compared it against new Fosi V3 mono blocks for the Class D competition, using a Topping E70 Velvet DAC, USB input from an iPad with Tidal and Apple Music Lossless. I used a pair of Infinity Reference Six and reworked Infinity Kappa 8.1s, both 4 way floor standers.

With the Infinity Reference Six pair, there was no audible difference between the Dayton A400 and the Fosi V3 mono blocks, using the same signal source chain. I will list the specs of the speakers below; these have 10" woofers.

With the Infinity Kappa 8.1 pair, there was a noticeable increase in low end presence with the Fosi V3 mono blocks compared to the Dayton A400. This was not an "earthshattering difference", but noticeable enough that several people I had listen them commented on it.
I see at least two possibilities here: first, both are over 30 year old speakers, and the Reference Six set has not been gone through. The old crossovers, caps, factory wiring, might not be sensitive enough at this point to show any difference in the signal from the two amplifiers. The Kappa 8.1s have been professionally worked over, new crossovers, all copper internal wiring, etc. Perhaps they present a "tighter system", able to show an audible difference.

Second possibility is that the Sixes being more sensitive, present less load at given volume, and likely the 10" drivers aren't drawing enough current to audibly show any difference between the amps. The Kappa 8.1s are less sensitive overall, presenting higher load at volume, and the larger 12" drivers might be working the amps just enough that we were able to discern a small difference between them.

Hope this little experiment can help anyone that's curious. The Dayton A400 is a fine AB amp for $499. It' s large, heavy, and will likely last a good while. However, with discerning enough speakers, the latest similar priced Class D mono block amps seem just a bit better.

Speakers used:
Infinity Reference Six Specs:
impedance: 6 ohms
power rating: 35 - 225 watts
frequency response: 35Hz - 40,000Hz
crossover frequency: 200Hz, 1,500Hz, 4,000Hz
sensitivity: 90dB
woofer: 10" IMG (902-4599)
mid-bass: 6" IMG (902-4338)
midrange: 5" IMG (902-4585)
tweeter: EMIT-R (902-4578)

Infinity Kappa 8.1 Specs:
Nominal Impedance: 6 ohms
Power Rating: 40 to 300 watts RMS
Frequency Response: 32Hz-35kHz
Crossover Frequencies: 180Hz, 700Hz, 4.7kHz
Sensitivity: 89dB
woofer: 12" IMG Woofer
mid-bass: 6-1/2" Mid-Bass Coupler
midrange: 3" Polydome
tweeter: EMIT-R

 

[AetherDrive]

Long time reader, but finally something I can possibly help out with, so my first post here.

After seeing the price drop on the Dayton A400, I pulled the trigger and gave it a try. I compared it against new Fosi V3 mono blocks for the Class D competition, using a Topping E70 Velvet DAC, USB input from an iPad with Tidal and Apple Music Lossless. I used a pair of Infinity Reference Six and reworked Infinity Kappa 8.1s, both 4 way floor standers.

With the Infinity Reference Six pair, there was no audible difference between the Dayton A400 and the Fosi V3 mono blocks, using the same signal source chain. I will list the specs of the speakers below; these have 10" woofers.

With the Infinity Kappa 8.1 pair, there was a noticeable increase in low end presence with the Fosi V3 mono blocks compared to the Dayton A400. This was not an "earthshattering difference", but noticeable enough that several people I had listen them commented on it.
I see at least two possibilities here: first, both are over 30 year old speakers, and the Reference Six set has not been gone through. The old crossovers, caps, factory wiring, might not be sensitive enough at this point to show any difference in the signal from the two amplifiers. The Kappa 8.1s have been professionally worked over, new crossovers, all copper internal wiring, etc. Perhaps they present a "tighter system", able to show an audible difference.

Second possibility is that the Sixes being more sensitive, present less load at given volume, and likely the 10" drivers aren't drawing enough current to audibly show any difference between the amps. The Kappa 8.1s are less sensitive overall, presenting higher load at volume, and the larger 12" drivers might be working the amps just enough that we were able to discern a small difference between them.

Hope this little experiment can help anyone that's curious. The Dayton A400 is a fine AB amp for $499. It' s large, heavy, and will likely last a good while. However, with discerning enough speakers, the latest similar priced Class D mono block amps seem just a bit better.

Speakers used:
Infinity Reference Six Specs:
impedance: 6 ohms
power rating: 35 - 225 watts
frequency response: 35Hz - 40,000Hz
crossover frequency: 200Hz, 1,500Hz, 4,000Hz
sensitivity: 90dB
woofer: 10" IMG (902-4599)
mid-bass: 6" IMG (902-4338)
midrange: 5" IMG (902-4585)
tweeter: EMIT-R (902-4578)

Infinity Kappa 8.1 Specs:
Nominal Impedance: 6 ohms
Power Rating: 40 to 300 watts RMS
Frequency Response: 32Hz-35kHz
Crossover Frequencies: 180Hz, 700Hz, 4.7kHz
Sensitivity: 89dB
woofer: 12" IMG Woofer
mid-bass: 6-1/2" Mid-Bass Coupler
midrange: 3" Polydome
tweeter: EMIT-R

Hi there thank you for the write up, there‘s very little out there for this amplifier and it seems to fit the bill for what I’m looking. I was wondering if you could let me know whether the Dayton A400 presents any hiss if you put your ears up to your tweeter?

 

[ss1976]

Hi there! So my smart ass answer while sitting on my patio drinking a beer is, this probably isn't the optimal listening position when listening to your music. LOL Are you asking if there's any noise present when no music is playing? I did notice when I had the A400 set at 100% there was some audible noise if I put my ear up to the speaker. I currently set the amp knob at roughly 80% and the noise isn't audible. I did have a ground loop hum initially due to using RCA cables and the trigger cable together. I ended up building an optical switch for the trigger cable using a cheap circuit off of amazon. If you are using XLR connectors I don't believe you will have this issue. If you're looking for an ab amplifier for around $500 I recommend it. I can't speak for the solid state stuff. Haven't tried it yet. Have a nice weekend!

 

[AetherDrive]

Hi there! So my smart ass answer while sitting on my patio drinking a beer is, this probably isn't the optimal listening position when listening to your music. LOL Are you asking if there's any noise present when no music is playing? I did notice when I had the A400 set at 100% there was some audible noise if I put my ear up to the speaker. I currently set the amp knob at roughly 80% and the noise isn't audible. I did have a ground loop hum initially due to using RCA cables and the trigger cable together. I ended up building an optical switch for the trigger cable using a cheap circuit off of amazon. If you are using XLR connectors I don't believe you will have this issue. If you're looking for an ab amplifier for around $500 I recommend it. I can't speak for the solid state stuff. Haven't tried it yet. Have a nice weekend!

Thank you very much for the quick response, it did make me chuckle. PM’ed you to further explain my question.

 

[DrPop]

Hi there thank you for the write up, there‘s very little out there for this amplifier and it seems to fit the bill for what I’m looking. I was wondering if you could let me know whether the Dayton A400 presents any hiss if you put your ears up to your tweeter?

Hi, sorry for the delay in my reply. I do believe there was just a faint "hiss" out the tweeters, but only if you had your ear right up next to them. Completely inaudible at more than a few inches away. Certainly not an issue, as it's no more than you might get with a tube preamp or anything similar in the chain.
If you're after a powerful Class-AB amp and not making the jump to Class D, like ss1976 said above, I would recommend it. Not sure what speakers you are looking to pair with it, but if your woofer drivers are in the 8 - 10 inch or smaller range, you will have serious volume for days - and at less than $500!

 

[AetherDrive]

No worries brother, I did go ahead and make the purchase but it’s good to build a consensus. Thank you for replying and letting me know

 

[JD666]

I got this for the $499 price, and hooked it up the S3 streamer. Extremely satisfied with the performance. Comparison against: NAD C338, Fosi BT20A Pro, Fosi BT20 Pro max and this simply has more oomph, depth and bass compared to those 3 even at comparable listening volumes. Class D may be all that they claim it is, but for $499, this is a powerful amp to have available for those (like me) who tinker around with their sound setups.

 

[ss1976]

Thanks. Leaning towards the NCx252MP.
I messaged Buckeye about the build time

Hi there! Did you end up getting the Buckeye? If so, how goes it?

 

[rjp]

Hi there! Did you end up getting the Buckeye? If so, how goes it?

I ordered it 4 weeks ago and no word yet. I ordered the 2 Chan purifi. I guess I should email to inquire.

I haven’t been too concerned because I’m really loving the Audiolab 9000p and it’s hard to imagine how the buckeye could be even better. Well the only way to know is to listen to both side by side for a good while.

 

[ss1976]

I ordered it 4 weeks ago and no word yet. I ordered the 2 Chan purifi. I guess I should email to inquire.

I haven’t been too concerned because I’m really loving the Audiolab 9000p and it’s hard to imagine how the buckeye could be even better. Well the only way to know is to listen to both side by side for a good while.

Thanks for the update and good luck! Hope it arrives soon.

 

[AetherDrive]

A400 just arrived, it is a chonker for sure.