Stereophile Amplification Product of the Year

[rdenney]

Musical just means not hurting your ears as much.

Musical to me means that tubas sound like tubas and not like euphoniums, and French horns sound like French horns and not flugelhorns.

I would like to be able to distinguish between the sound of a very large tuba with a "normal-size" tuba, and that is already completely beyond what most recordings even contain. But I've heard recordings played on demonstration systems where the bass instruments sounded like their siblings an octave higher, and I assume harmonic distortion is at least partly to blame.

But I calibrated my sound concept of these instruments with live music, much of it on stage, not listening to so-called high-end distortion machines.

Rick "with all due respect" Denney

 

[AdrianusG]

Thread was worth it just for that cartoon!

Indeed, as i already said before in some other thread (or perhaps this one?) Gary Larson is Awesome!

 

[Hauxon]

Musical to me means that tubas sound like tubas and not like euphoniums, and French horns sound like French horns and not flugelhorns.

I would like to be able to distinguish between the sound of a very large tuba with a "normal-size" tuba, and that is already completely beyond what most recordings even contain. But I've heard recordings played on demonstration systems where the bass instruments sounded like their siblings an octave higher, and I assume harmonic distortion is at least partly to blame.

But I calibrated my sound concept of these instruments with live music, much of it on stage, not listening to so-called high-end distortion machines.

Rick "with all due respect" Denney

What's not audible is indeed not audible and distortion does not change French horns into flugelhorns when not audible. By saying a distortion is "musical" just means it's in pitch with the tone (instrument) and thus harder to detect and when it comes into play it's not a total disaster (like 3rd order or higher). Having second-order harmonic distortion does not make an amp any better, it just gets away with more since you can't hear it.

Here's a link to a harmonic generator where you can add harmonics to sine wave. The AN amp is rater 8W per channel, has about 1% at 1W and 4% at 8W. Add 0.01 to the 2nd harmonic and then to the 3rd. Then do the same with 0.4. Not a proof to anything but fun to explore.
Additive synthese waveform generator

I can understand the listening pleasure with the AN amp and a dash of fairy dust doesn't make it any lesser. However there is nothing new to it and no technological advancement involved, just silver and oil caps and some large transistors. It should have been the amp of the year 1950. Peace out!

 

[Robin L]

What's not audible is indeed not audible and distortion does not change French horns into flugelhorns when not audible. By saying a distortion is "musical" just means it's in pitch with the tone (instrument) and thus harder to detect and when it comes into play it's not a total disaster (like 3rd order or higher). Having second-order harmonic distortion does not make an amp any better, it just gets away with more since you can't hear it.

Here's a link to a harmonic generator where you can add harmonics to sine wave. The AN amp is rater 8W per channel, has about 1% at 1W and 4% at 8W. Add 0.01 to the 2nd harmonic and then to the 3rd. Then do the same with 0.4. Not a proof to anything but fun to explore.
Additive synthese waveform generator

I can understand the listening pleasure with the AN amp and a dash of fairy dust doesn't make it any lesser. However there is nothing new to it and no technological advancement involved, just silver and oil caps and some large transistors. It should have been the amp of the year 1950. Peace out!

I think you simply don't understand how harmonics work. Doubling is doubling. It's an effect found in old-school piano playing, where the bottom octave of the instrument is goosed by playing the next octave up or down. In classical music it obscures the composer's intention. Having the next octave up being played when it wasn't intended gives off a different sound, a different harmonic quality, than a composer intended. Of course, with most species of popular music it can be attributed to the luxury of improvisation. But as regards fidelity to original intent, it's an obvious and undesirable form of distortion.

 

[rdenney]

What's not audible is indeed not audible and distortion does not change French horns into flugelhorns when not audible. By saying a distortion is "musical" just means it's in pitch with the tone (instrument) and thus harder to detect and when it comes into play it's not a total disaster (like 3rd order or higher). Having second-order harmonic distortion does not make an amp any better, it just gets away with more since you can't hear it.

...

I can hear it when it's above a threshold. But let's look at the measurements:
(graphics excerpted from the Stereophile measurements, here.)

The figure title was written by JA. Note that this is with a small signal, which should be well down around the 1% distortion value or lower. That's only partway up the distortion graph:

And even there, I see lots of harmonics other than the second overtone. The notion that this amp only produces second-order harmonic distortion is just not correct. Drive it to anything like the power one would need to hear full-range music into realistic loudspeakers, and the clipping characteristics will be much worse. Yes, the amp does not clip hard, but it still clips and adds a range of overtones not present in the music. Thus unquestionably muddies the music if the total distortion is high enough, and it would be very easy for this amp to be driven to approaching 10% distortion (-20 dB) at the amp's rated power, even if it doesn't sound like what people think of as distortion with square-wave clipping. That will be abundantly audible.

Finally, look at how much the frequency response varies with changing loads. This amp is highly load-dependent. These variations should certainly be audible, and more pronounce with more difficult speakers. That doesn't mean they are objectionable in absolute terms in any one case, but they are certainly not what was on the recording.

Thank you JA for providing the data to make an educated evaluation.

Rick "distortion machine, indeed" Denney

 

[fpitas]

they are certainly not what was on the recording

And that's always the take-away. Some people like it, no doubt. But it's an effects box.

 

[Hauxon]

I think you simply don't understand how harmonics work. Doubling is doubling. It's an effect found in old-school piano playing, where the bottom octave of the instrument is goosed by playing the next octave up or down. In classical music it obscures the composer's intention. Having the next octave up being played when it wasn't intended gives off a different sound, a different harmonic quality, than a composer intended. Of course, with most species of popular music it can be attributed to the luxury of improvisation. But as regards fidelity to original intent, it's an obvious and undesirable form of distortion.

If it’s audible it is audible, if not it’s not. Has little to do with composers or their intent.

As for when you start to hear it you would probably prefer it being in in pitch with the music instead of falling apart. It will be closer to the timbre of the instruments or “composers intent” than noise. That’s why we don’t have any high-en flea watt transistor amps.

And funny you speak of instruments and their harmonics and acoustics. A recording is a recording of a performance in some room or hall with all sorts of acoustics and harmonies derived from that event. It will never be a 100% exact representation in your home. Your room and speakers will matter 1000 times more than inaudible distortion.

 

[rdenney]

If it’s audible it is audible, if not it’s not. Has little to do with composers or their intent.

As for when you start to hear it you would probably prefer it being in in pitch with the music instead of falling apart. It will be closer to the timbre of the instruments or “composers intent” than noise. That’s why we don’t have any high-en flea watt transistor amps.

And funny you speak of instruments and their harmonics and acoustics. A recording is a recording of a performance in some room or hall with all sorts of acoustics and harmonies derived from that event. It will never be a 100% exact representation in your home. Your room and speakers will matter 1000 times more than inaudible distortion.

I don't want the amp adding the room. I'm happy with the room the instrument was recorded in, if it's a good room. I can hear the recorded room even in my home, because it's on the recording and my system remains fairly true to it.

If the recording is bad, I don't want the amp fixing it, because the fix for one recording will only work for that recording. Why is that so hard to understand?

Acceptable clipping is still clipping, and clipping is easy enough to avoid these days at listenable power output, even with tube amps.

Rick "gotta go" Denney

 

[Hauxon]

I can hear it when it's above a threshold. But let's look at the measurements:
(graphics excerpted from the Stereophile measurements, here.)

View attachment 330378
The figure title was written by JA. Note that this is with a small signal, which should be well down around the 1% distortion value or lower. That's only partway up the distortion graph:

View attachment 330380
And even there, I see lots of harmonics other than the second overtone. The notion that this amp only produces second-order harmonic distortion is just not correct. Drive it to anything like the power one would need to hear full-range music into realistic loudspeakers, and the clipping characteristics will be much worse. Yes, the amp does not clip hard, but it still clips and adds a range of overtones not present in the music. Thus unquestionably muddies the music if the total distortion is high enough, and it would be very easy for this amp to be driven to approaching 10% distortion (-20 dB) at the amp's rated power, even if it doesn't sound like what people think of as distortion with square-wave clipping. That will be abundantly audible.

Finally, look at how much the frequency response varies with changing loads. This amp is highly load-dependent. These variations should certainly be audible, and more pronounce with more difficult speakers. That doesn't mean they are objectionable in absolute terms in any one case, but they are certainly not what was on the recording.

View attachment 330379

Thank you JA for providing the data to make an educated evaluation.

Rick "distortion machine, indeed" Denney

Very informative. These amps obviously need very sensitive speakers or a crossover for realistic listening levels for demanding music. So it severly limits your choices. Preferably you would use it with something like La Scala. I’m not sure where my 300B will end up. Maybe it will continue to be my office amp for low listening levels. Maybe I will use with active crossover for the tweeter array of my Polk SRS 1.2TL. At least I didn’t pay 15k for it not do I claim it’s the product of the year.

 

[DonH56]

When you say neutral electronics and correctly designed speakers it is still objective. You might assume a tube colorizes the signal and it truly does when reaching it's limits but a non overdriven tube might still be called the purest form amplification that does not need to remedy the 0.7V operating threshold of a silicon transistor, it simply amplifies what you serve it. Like I said it's objective and depends on personal perspective. ..and for speakers what is correctly designed? Are horn acoustics incorrect? How about the cabinet, or open baffle? ...crossover components and design?? What's correct for who and what?

Bias circuits are what "remedy" the turn-on voltage needed by a tube or a transistor. Neither device amplifies without proper biasing, and either has a "threshold" you must "overcome" for proper (linear) operation. Either circuit adds noise and distortion, though typically a SS circuit adds less in practice (often a design choice on the tube designers' parts IMO). A proper tube design and proper SS design should both have no sound of their own. And you can easily create a single-ended transistor-based amplifier that has even harmonics dominant. The biggest issue with tube amps for me is their high output impedance that limits the speakers you can drive. Many, perhaps most, speakers these days have pretty wide impedance variation over frequency and it is more difficult for many (most?) tube amplifiers to provide flat response into such a load. You must either choose speakers that complement the amp or choose speakers that, with the amp, modify the sound in a way pleasing to you. Either way limits your choice in speakers.

 

[Hauxon]

I don't want the amp adding the room. I'm happy with the room the instrument was recorded in, if it's a good room. I can hear the recorded room even in my home, because it's on the recording and my system remains fairly true to it.

If the recording is bad, I don't want the amp fixing it, because the fix for one recording will only work for that recording. Why is that so hard to understand?

Acceptable clipping is still clipping, and clipping is easy enough to avoid these days at listenable power output, even with tube amps.

Rick "gotta go" Denney

Nobody wants clipping. I’m just saying it doesn’t hurt as much. Luckily you can listen without clipping with sensitive speakers and restraining yourself with the listening level.

 

[617]

And that's always the take-away. Some people like it, no doubt. But it's an effects box.

The irony with this comment is that the level of distortion in tube electronics is almost always beneath any reasonable threshold of audibility. You have to be really committed to distortion for it to be audible.

That was the genius of those 300B amplifiers that produce like 1W. Not only are they running right at their margins, but to get any output, you need huge weird sounding speakers, which guarantees a differentiated sound.

 

[Robin L]

More from JA's measurements:

Due to masking, in itself the level of the second harmonic may not result in audible distortion, but this will only be true if it is not accompanied by intermodulation distortion. With the Meishu Tonmeister's 4 ohm taps driving an equal mix of 19 and 20kHz tones at 1Wpc peak into 8 ohms (fig.13), the 1kHz difference product lay just below –50dB (0.3%), with the higher-order products at 18 and 21kHz 10dB lower in level. This is marginal performance, in my opinion.

 

[fpitas]

IMD is the fly in the ointment.

 

[Hauxon]

To further stir the pot like to add few more notes.

Some seem worried about the amp being so under powered that it will be constantly clipping with powerful passages. Note that DeVORE Orangutan O/96 speakers were used be the in the Stereophile review. These speakers sensitivity is quite high 96db. Most of us know that you need roughly double the power to increase loudness by 3db. So if we calculate backwards we find out 8w into a 96db speaker will give you the same SPL as 64W into a reletively inefficient 87db speaker. If the Klipsch La Scala sensitivity is as advertised 105db it would deliver the same SPL as 512W into a 87db speaker! So an 8W amp or even only 3W can play relatively loud without straining or clipping if fed into a sensitive loudspeaker. This is of course makes your choice of speakers very narrow.

As discussed earlier second-order harmonic (tube) distortion is not audible to humans to the same extent as the high-order harmonics (of a transistor). Even if the measurements look shocking I assume distortion is simply inaudible with the AN amp and thus not a real factor when evaluating it for listening. When distortion can't be heard other factors that affect the signal matter more, like the quality of the components, number of components and simplicity of the audio path. Here's where the Audio Note Meishu probably makes it homerun.

Another thing to take into account is the single ended class A design. Not a tube thing but design thing. Single ended class A does not cut the waveform into two parts like class B. This is inefficient but still is the purest form of waveform amplification. That's why many of our transistor amps are so called class AB where the are biased to operate in class A with low power and switch to class B for more power. Class B simply is inferior, the embedded image describes how crossover deformation of the signal is the result of class B amplification. People have found ways to lessen the effect but using class A you avoid baking the signal during amplification.

There is simply much more to amplifier performance than measured distortion. I suggest reading the following article by amp guru Nelson Pass where he talks about lot of what we have discussed in this thread. And note, he is a transistor guy and his company makes transistor amps.

Single-Ended Class A by Nelson Pass

 

[DonR]

Nobody makes a Class B audio amp. They are all Class A, AB or D (maybe G or H but those are rare now).

 

[pablolie]

In my opinion, just like everywhere, there are standard and outlier use cases in audio.

This clearly is an outlier thing. Personally I could not be less interested. But clearly some think this suits their use case. And I never disagree with educated preference and willingness to pay for it. A Rolls Royce will never ever win any race again. Doesn't matter to those who bankroll that evolutionary aspect of luxury cars.

 

[Hauxon]

Nobody makes a Class B audio amp. They are all Class A, AB or D (maybe G or H but those are rare now).

Class AB is class B. But it’s biased for class A for the first few (5-10) watts.

 

[DonR]

Class AB is class B. But it’s biased for class A for the first few (5-10) watts.

Yes, and I see now you noted that in your brief. Class B has a horrendous crossover distortion profile which is why it is never used. Class AB can easily have distortion well below audible levels, however. Class A is not noticeably "purer" once AB distortion exceeds the threshold of audibility which isn't too difficult for distortion.

 

[Galliardist]

I get the feeling that the defence of this kind of amp comes in two parts:
1) Actually, it sounds the same as the latest low distortion/low SINAD wonder amp, because you can't hear the distortion at low/at normal listening levels.
2) People prefer the sound to that of the latest low distortion... you get the picture.

I don't know why Stereophile reviewers did really choose the amp under discussion as their amplification product of the year, but it certainly wasn't because of reason number 1.

I suspect that it was chosen precisely to continue the current editor's intention to recognise and provide for those people who spend their lives hunting for a particular magic sound, as we know from previous comment that they are the people he respects in audio.