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HifiBerry AMP60 Stereo Amplifier Review

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 55 32.9%
  • 2. Not terrible (postman panther)

    Votes: 90 53.9%
  • 3. Fine (happy panther)

    Votes: 19 11.4%
  • 4. Great (golfing panther)

    Votes: 3 1.8%

  • Total voters
    167

dananski

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HIFIBERRY AAMP60 RPi stereo amplifier measurements.png
The continuation of distortion into higher harmonics reminds me of Dan Foley from Audio Precision talking at Canjam bringing up old research indicating that higher order harmonics are more noticeable (less psychoacoustic masking) and of stronger detriment to the audio. Listening tests showed subjective preferences that were more closely correlated to a score strongly weighted to higher harmonics than to raw THD.

Is this idea well established at this point? It makes sense to me as a musician (well more of a music theory nerd), since the first harmonic is an octave so fits ok with all fundamentals (though changes the instrument tone and increases dissonance in certain spread voicings), while the second harmonic is a perfect fifth above that and would cause additional dissonance in some chords and scales, and the harmonics beyond that keep adding more extreme dissonances. Also the note being played is (usually) not a perfect sine wave, and applying dissonant harmonics to what is already a harmonic series is going to get to some ugly intervals very fast. The higher harmonics also don't correspond to the typical equal temperament tunings we use, so they'll also clash a bit with anything else playing around that frequency in the music, particularly anything hitting a minor third or major sixth to the fundamental, since that's where the tuning difference is biggest.

At the same time, our sensitivity falls at the extremes, so I'm not sure how much you'd care about, for example, a faint 13th harmonic on 1KHz, if you can barely hear 14KHz anyway.
 

AndreaT

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The continuation of distortion into higher harmonics reminds me of Dan Foley from Audio Precision talking at Canjam bringing up old research indicating that higher order harmonics are more noticeable (less psychoacoustic masking) and of stronger detriment to the audio. Listening tests showed subjective preferences that were more closely correlated to a score strongly weighted to higher harmonics than to raw THD.

Is this idea well established at this point? It makes sense to me as a musician (well more of a music theory nerd), since the first harmonic is an octave so fits ok with all fundamentals (though changes the instrument tone and increases dissonance in certain spread voicings), while the second harmonic is a perfect fifth above that and would cause additional dissonance in some chords and scales, and the harmonics beyond that keep adding more extreme dissonances. Also the note being played is (usually) not a perfect sine wave, and applying dissonant harmonics to what is already a harmonic series is going to get to some ugly intervals very fast. The higher harmonics also don't correspond to the typical equal temperament tunings we use, so they'll also clash a bit with anything else playing around that frequency in the music, particularly anything hitting a minor third or major sixth to the fundamental, since that's where the tuning difference is biggest.

At the same time, our sensitivity falls at the extremes, so I'm not sure how much you'd care about, for example, a faint 13th harmonic on 1KHz, if you can barely hear 14KHz anyway.
The continuation of distortion into higher harmonics reminds me of Dan Foley from Audio Precision talking at Canjam bringing up old research indicating that higher order harmonics are more noticeable (less psychoacoustic masking) and of stronger detriment to the audio. Listening tests showed subjective preferences that were more closely correlated to a score strongly weighted to higher harmonics than to raw THD.

Is this idea well established at this point? It makes sense to me as a musician (well more of a music theory nerd), since the first harmonic is an octave so fits ok with all fundamentals (though changes the instrument tone and increases dissonance in certain spread voicings), while the second harmonic is a perfect fifth above that and would cause additional dissonance in some chords and scales, and the harmonics beyond that keep adding more extreme dissonances. Also the note being played is (usually) not a perfect sine wave, and applying dissonant harmonics to what is already a harmonic series is going to get to some ugly intervals very fast. The higher harmonics also don't correspond to the typical equal temperament tunings we use, so they'll also clash a bit with anything else playing around that frequency in the music, particularly anything hitting a minor third or major sixth to the fundamental, since that's where the tuning difference is biggest.

At the same time, our sensitivity falls at the extremes, so I'm not sure how much you'd care about, for example, a faint 13th harmonic on 1KHz, if you can barely hear 14KHz anyway.
Nice post. A common misconception is that when amplifiers, like musical instruments, produce harmonics added to a fundamental, it is “not a big deal” because they behave thus like musical instruments. Assonances and dissonances are certainly appreciated in their analog additions and subtractions, and their contribution to the acoustic signature of music halls and listening rooms. I tried and failed to self-study advanced acoustics…
 

mctron

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Thanks for the review, always wondered how these things would fare.. Hard to find the use case but they are neat nonetheless
 

Tks

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Worse based on what? One is a DAC/HP amp, the other is an analog speaker amplifier. The Apple dongle is certainly worse at driving speakers.

SINAD?
 

PeteL

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OK, so I’ll assume best Sinad at 1k, into which load would you say is your benchmark when trying to rank headphone amps and speaker amps on the same scale, at which power or voltage output? I admit I am being cynical here, but just to show SINAD, on it’s own, don’t mean much, you need testing conditions. And testing conditions will vary depending what type of electronics you are measuring. It’s apple to oranges, and SINAD is just one measurment of many to assess performance, Power is arguably, or in my book the most important one, noise floor or dynamic range would probably rank high too since it’s way more audible than distortion, plenty of other considerations too, Bottom line, it’s already a bit diminutive to rank device of the same type based only on one metric, Now mixing them all up on this sole metric is to be honest totally meaningless. Would you include Headphones and speakers THD measurments on that same scale?
 

Tks

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I admit I am being cynical here,

Well firstly, I don't know if you're being cynical, but if I had to give an arm chair psych evaluation, perhaps upset with something recently that I seemed to have provoked for reasons unknown to me. Maybe you just would like to talk to someone you think holds some wacky views compared to your own. I'd be glad to conversate.

OK, so I’ll assume best Sinad at 1k, into which load would you say is your benchmark when trying to rank headphone amps and speaker amps on the same scale, at which power or voltage output? On it’s own, don’t mean much, you need testing conditions.

Sure, I look at 1.8-2V performance for unbalanced loads, and 4-4.5V for balanced loads. That's at least what I hope to see when SINAD metrics are revealed here or at L7audio reviews for instance. Speaker amps I don't even use as I only used powered varients (not much a speaker guy, just use Vanatoo T1E's) so I wouldn't even be able to tell you what the objective performance of the DAC and AMP unit in that device even is. Speaker amp performance are a curiosity at best for me, simply because it's a bit puzzling to see their performance (THD/Noise metrics mostly) stagnate so much only up until recently when Topping at least on that performance front has finally dethroned the half-decade+ champ, the ABH2. I know the ABH2 was overtaken in a few particular metrics by Hypex modules, but that didn't seem all that impressive to me, since they weren't offered in a finished product in as clean of a package as the ABH2.

As for headphone amps and the like, I know you say "on it's own, don't need much", the metrics provided by measurements done here and at l7audio haven't led me to a device that performed poorly irrespective of load. 300ohm, 600ohm, 20ohm, 15ohm, doesn't matter for the ones I posses, all can be easily driven to an output that's deafening. I don't even have a dedicated amp anymore since I use an RME DAC. There's the 50mV output which I actually value more than actual higher voltage SINAD these days, and that SINAD is 92dB. Shy of the recent record breaking effort again from Topping in this metrics, but at 4dB shy of CD quality, I think I'll live for the most part.

And testing conditions will vary depending what type of electronics you are measuring.

Sure, but I'm not sure why this needs spelling out. You can go further and talk about conditions varying based on even things like temperature. But again, nothing really that needs mentioning because we both understand this, and I see no disagreement.

It’s apple to oranges, and SINAD is just one measurment of many to assess performance, Power is arguably, or in my book the most important one, noise floor or dynamic range would probably rank high too since it’s way more audible than distortion,

Sorry but it's not clear what you think you're reaping here by telling me I can't compare a speaker amp's SINAD to a headphone dongle's SINAD. At that point I could take it further and call up other metrics. Are you going to say those are also going to maintain apples to oranges outlook? When does this end exactly, or is it virtually impossible to compare these devices PERIOD beyond output power? Or do you think even THAT can't be compared?

I agree for speakers, power is paramount. Almost no point in clean measurements on an expensive speaker amp, if it can't drive and SPL you want out of your speakers. And this seems to always be in short supply seemingly. I'm sure you'd agree this importance pragmatically is FAR less in the desktop amp and to some extent the dongle realm, simply due to the reality that many of them are currently pretty powerful enough in comparison to the constant hunt for more clean max-power for passive speakers.

Oh and I disagree with your "noise is more audible" claim. Distortion to my ears is more audible, or at least harder to ignore than distortion if each were being rendered at similar output levels.

Maybe this is a speaker thing, since I know speaker amps or speakers in general suffer all sorts of noise at times, and things like tweeter hissing, so I imagine noise is a problem perhaps before distortion for most folk? Idk, you tell me where I'm at here. I see a decent amount of speaker amps that can produce decent SNR, but are pretty garbo in the distortion department.

Bottom line, it’s already a bit diminutive to rank device of the same type based only on one metric,

I mean sure, it may be diminutive, but this isn't particularly a place I feel where the fan base will rally for excuses for devices that are being trounced by old, rinky dinky headphone dongles in cleanliness of signal integrity. Irrespective of how much power one produces over the other. This sort of sentiment might have been able to fly before iPhones came pre-packed with these dongles. Time has moved on, expectations have moved up, standards in general have also moved up. I personally don't think ANY consumer (non-business/industry) device come the year 2023 (just so we can neatly wrap this idea up) shouldn't exist on the market that can't clear CD quality for SINAD, let alone SNR. Don't personally care if it was a $100 amp that allowed easy 1000W output at whatever speaker load. It's about time some bottom standard be established, in the same way no television on the face of this planet will ever be sold to the general audience with interlaced resolutions exclusively, or something like 720p maximum resolution.

Now mixing them all up on this sole metric is to be honest totally meaningless. Would you include Headphones and speakers THD measurments on that same scale?

Oh so you're one of those people. "1kHZ SINAD = 100% UTTERLY MEANINGLESS, Literally ZERO informational value in any possible conceivable way". I take it this is the reason for your slight outburst toward me, and all the questioning?

As for headphone and speaker THD measurements. Of course I wouldn't consider holding them to the same standard. In the same way I don't hold sole AMPs, to the same standard as sole DACs. Simply because SINAD swings would be dependent at many times due to something simple like output impedance of the device they're hooked up to and other such considerations. CD quality 1khHz DAC/AMP SINAD standard doesn't equal to me expecting every single speaker and headphone now also having to clear THD threshold of hearing at all frequencies, and at all output levels. I understand the state of the industry currently that physical transducers won't be performing like bits in the digital realm. So no I wouldn't hold them "on that same scale" (whatever that actually means, though I hope I got the meaning in my explanation).

--------------------------------------------------------------------------------------

I replied to you here as opposed to PM's where it actually would be more appreciated by passer-by's not having to scroll through my Wall of China text. But I left it here just in case anymore of the "Down with the 1kHz SINAD at all costs because it's utterly useless" gang feels the need to probe me for my stance. I only ask that the rest of our discussion on this topic doesn't spam this thread further, so please PM me your reply. As you can tell, I like to reply to every single portion of people's posts that I feel I am capable of adequately replying to. This always leads to these annoyingly long posts that I don't know if I can ever truly tone down the character count for if I want to remain as informative as I desire.
 

tonycollinet

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Well firstly, I don't know if you're being cynical, but if I had to give an arm chair psych evaluation, perhaps upset with something recently that I seemed to have provoked for reasons unknown to me. Maybe you just would like to talk to someone you think holds some wacky views compared to your own. I'd be glad to conversate.



Sure, I look at 1.8-2V performance for unbalanced loads, and 4-4.5V for balanced loads. That's at least what I hope to see when SINAD metrics are revealed here or at L7audio reviews for instance. Speaker amps I don't even use as I only used powered varients (not much a speaker guy, just use Vanatoo T1E's) so I wouldn't even be able to tell you what the objective performance of the DAC and AMP unit in that device even is. Speaker amp performance are a curiosity at best for me, simply because it's a bit puzzling to see their performance (THD/Noise metrics mostly) stagnate so much only up until recently when Topping at least on that performance front has finally dethroned the half-decade+ champ, the ABH2. I know the ABH2 was overtaken in a few particular metrics by Hypex modules, but that didn't seem all that impressive to me, since they weren't offered in a finished product in as clean of a package as the ABH2.

As for headphone amps and the like, I know you say "on it's own, don't need much", the metrics provided by measurements done here and at l7audio haven't led me to a device that performed poorly irrespective of load. 300ohm, 600ohm, 20ohm, 15ohm, doesn't matter for the ones I posses, all can be easily driven to an output that's deafening. I don't even have a dedicated amp anymore since I use an RME DAC. There's the 50mV output which I actually value more than actual higher voltage SINAD these days, and that SINAD is 92dB. Shy of the recent record breaking effort again from Topping in this metrics, but at 4dB shy of CD quality, I think I'll live for the most part.



Sure, but I'm not sure why this needs spelling out. You can go further and talk about conditions varying based on even things like temperature. But again, nothing really that needs mentioning because we both understand this, and I see no disagreement.



Sorry but it's not clear what you think you're reaping here by telling me I can't compare a speaker amp's SINAD to a headphone dongle's SINAD. At that point I could take it further and call up other metrics. Are you going to say those are also going to maintain apples to oranges outlook? When does this end exactly, or is it virtually impossible to compare these devices PERIOD beyond output power? Or do you think even THAT can't be compared?

I agree for speakers, power is paramount. Almost no point in clean measurements on an expensive speaker amp, if it can't drive and SPL you want out of your speakers. And this seems to always be in short supply seemingly. I'm sure you'd agree this importance pragmatically is FAR less in the desktop amp and to some extent the dongle realm, simply due to the reality that many of them are currently pretty powerful enough in comparison to the constant hunt for more clean max-power for passive speakers.

Oh and I disagree with your "noise is more audible" claim. Distortion to my ears is more audible, or at least harder to ignore than distortion if each were being rendered at similar output levels.

Maybe this is a speaker thing, since I know speaker amps or speakers in general suffer all sorts of noise at times, and things like tweeter hissing, so I imagine noise is a problem perhaps before distortion for most folk? Idk, you tell me where I'm at here. I see a decent amount of speaker amps that can produce decent SNR, but are pretty garbo in the distortion department.



I mean sure, it may be diminutive, but this isn't particularly a place I feel where the fan base will rally for excuses for devices that are being trounced by old, rinky dinky headphone dongles in cleanliness of signal integrity. Irrespective of how much power one produces over the other. This sort of sentiment might have been able to fly before iPhones came pre-packed with these dongles. Time has moved on, expectations have moved up, standards in general have also moved up. I personally don't think ANY consumer (non-business/industry) device come the year 2023 (just so we can neatly wrap this idea up) shouldn't exist on the market that can't clear CD quality for SINAD, let alone SNR. Don't personally care if it was a $100 amp that allowed easy 1000W output at whatever speaker load. It's about time some bottom standard be established, in the same way no television on the face of this planet will ever be sold to the general audience with interlaced resolutions exclusively, or something like 720p maximum resolution.



Oh so you're one of those people. "1kHZ SINAD = 100% UTTERLY MEANINGLESS, Literally ZERO informational value in any possible conceivable way". I take it this is the reason for your slight outburst toward me, and all the questioning?

As for headphone and speaker THD measurements. Of course I wouldn't consider holding them to the same standard. In the same way I don't hold sole AMPs, to the same standard as sole DACs. Simply because SINAD swings would be dependent at many times due to something simple like output impedance of the device they're hooked up to and other such considerations. CD quality 1khHz DAC/AMP SINAD standard doesn't equal to me expecting every single speaker and headphone now also having to clear THD threshold of hearing at all frequencies, and at all output levels. I understand the state of the industry currently that physical transducers won't be performing like bits in the digital realm. So no I wouldn't hold them "on that same scale" (whatever that actually means, though I hope I got the meaning in my explanation).

--------------------------------------------------------------------------------------

I replied to you here as opposed to PM's where it actually would be more appreciated by passer-by's not having to scroll through my Wall of China text. But I left it here just in case anymore of the "Down with the 1kHz SINAD at all costs because it's utterly useless" gang feels the need to probe me for my stance. I only ask that the rest of our discussion on this topic doesn't spam this thread further, so please PM me your reply. As you can tell, I like to reply to every single portion of people's posts that I feel I am capable of adequately replying to. This always leads to these annoyingly long posts that I don't know if I can ever truly tone down the character count for if I want to remain as informative as I desire.
Do you have a TL;DR version of that? :p
 

sweetsounds

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But $44.90 is a little high, you can get a (finished) MA12070 Infineon-based amp for less than $25 on AliExpress: more power and most likely the same “fair” ranking (no actual data to corroborate).

This thing exists as a Raspberry Pi HAT with 40W and very good specs.

https://www.infineon.com/cms/en/product/evaluation-boards/kit_40w_amp_hat_zw/ (Video and device spec inside)

Device Spec is Audio Performance (PMP2), but we have to see if it measures in the module as well
◦ >101dB DNR (A-w, rel. to 1% THD+N power level)
◦ 140µV output integrated noise (A-w)

If it works as specified, it would drive small form factor amps to a new level.
 

tonycollinet

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This thing exists as a Raspberry Pi HAT with 40W and very good specs.

https://www.infineon.com/cms/en/product/evaluation-boards/kit_40w_amp_hat_zw/ (Video and device spec inside)

Device Spec is Audio Performance (PMP2), but we have to see if it measures in the module as well
◦ >101dB DNR (A-w, rel. to 1% THD+N power level)
◦ 140µV output integrated noise (A-w)

If it works as specified, it would drive small form factor amps to a new level.
Not available to buy at the moment though.

And the 40W is:
Up to 40W instantaneous peak output power with the Raspberry Pi official 5V/2.5A supply

I think only 7W continuous.
 

pseudoid

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Ah yes. Too lazy to correct. :)
Thank you @amirm!
Do you ever get to a point during your testing, where you say "Oh, [expletive deleted] fohget about it!" and stop testing the hardware... because the results' analysis will require a nose-clip or a gas-mask?
 

Kevinfc

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The Pi itself can be used as a basic streaming device. If combined with a proper DAC-hat (e.g. some products from Audiophonics or Allo) it becomes a more than capable DAC/preamp, actually everything you want it to be. Several of such implementations have been positively reviewed here at ASR.
Thanks, I’ll have to look those up.
 

Kevinfc

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The Pi is fine as a streamer as long as you're not expecting decent internal DAC solutions (With the exception of the ALLO BOSS 2 which measured excellently)

Connect it to an external DAC though and it performs as well as any other digital in / digital out streamer - at pretty much any price.
I use a PC Daphile streamer, I’ll have to look at the PI’s implementations.
 

damirj79

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This thing exists as a Raspberry Pi HAT with 40W and very good specs.

https://www.infineon.com/cms/en/product/evaluation-boards/kit_40w_amp_hat_zw/ (Video and device spec inside)

Device Spec is Audio Performance (PMP2), but we have to see if it measures in the module as well
◦ >101dB DNR (A-w, rel. to 1% THD+N power level)
◦ 140µV output integrated noise (A-w)

If it works as specified, it would drive small form factor amps to a new level.
Try with:

Its MA12070P in full power as RPi hat. It is even allowing to configure it as 2.0, 2.1, 4.0 and one channel.
 

tonycollinet

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Tks

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Do you have a TL;DR version of that? :p
Absolutely, SINAD is the most informative singular condensed metric I've come across. Nothing sets the stage for expectations better than it with respect to fidelity concerns. Alone it obviously isn't as imperative if you have a constrained set of concerns (like if you're a passive speaker enthusiast, you have far bigger troubles with respect to power output almost always a thing that is lacking, and perhaps like PeteL, this is a more informative metric for your buying needs). But across the spectrum of all audio output devices, SINAD hasn't really been topped as an aggregate metric as being the most informative for setting the stage of what to expect with the rest of a device's fidelity preservation capability.

PeteL disagrees with me in totality on this claim, he takes SINAD to be quite literally meaningless in all instances. Since there was pedantic detail in our conversation, I don't he means it's actually definitionally useless, but obviously at the very least, he does consider it useless from an informative value perspective with respect to his concerns it seems.
 
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