Difficult question 
There is no doubting the fact that Passlabs offerings are "hi end" & therefore Hifi & yet the amps will happily produce up to & possibly more than 0.1% distortion at a fair drive level. You see it's not so much about the level of the distortion but more about the type of distortion. If it's even harmonic then it actually sounds musical rather than degrading the sound, this is more through design though.
Any chip amp will be a class B or AB design & these tend to produce odd order harmonics which isn't so musical. 0.02% isn't bad at all though, a properly laid out PCB will probably result in a decent sounding amplifier. Compared to what's on offer at the local electrical retailers these days with there plastic midi systems with lots of lights & fireworks i think i'd rather go with what you are looking at
There is no doubting the fact that Passlabs offerings are "hi end" & therefore Hifi & yet the amps will happily produce up to & possibly more than 0.1% distortion at a fair drive level. You see it's not so much about the level of the distortion but more about the type of distortion. If it's even harmonic then it actually sounds musical rather than degrading the sound, this is more through design though.
Any chip amp will be a class B or AB design & these tend to produce odd order harmonics which isn't so musical. 0.02% isn't bad at all though, a properly laid out PCB will probably result in a decent sounding amplifier. Compared to what's on offer at the local electrical retailers these days with there plastic midi systems with lots of lights & fireworks i think i'd rather go with what you are looking at
There are only two "correct" answers to this question, imo:
- ZERO distortion
- A value of "distortion" that is usually below 1.0% AND also has a harmonic series that is not "objectionable" to the ear.
So, the second answer is the only practical one in the real world.
There has been much discussion of this issue here on DIYaudio and elsewhere. But recent research (Dr. Geddes), and some older research (D.E.L Shorter) both point to the same conclusion. That is, the ratios of harmonic spectra are more significant than any absolute number.
The problem with many chips and chipamps is that they often have objectionable ratios of harmonic distortion spectra.
Thus it can be shown in double blind tests that amps that have high and very low distortion can be grouped together by listeners, while other amps with either high or low distortion can be disliked by listeners - the difference being the spectra of distortion.
Of course, if you have a speaker that creates "nasties" on its own, the effect of the amp may be less evident or impossible to discern.
_-_-bear
- ZERO distortion
- A value of "distortion" that is usually below 1.0% AND also has a harmonic series that is not "objectionable" to the ear.
So, the second answer is the only practical one in the real world.
There has been much discussion of this issue here on DIYaudio and elsewhere. But recent research (Dr. Geddes), and some older research (D.E.L Shorter) both point to the same conclusion. That is, the ratios of harmonic spectra are more significant than any absolute number.
The problem with many chips and chipamps is that they often have objectionable ratios of harmonic distortion spectra.
Thus it can be shown in double blind tests that amps that have high and very low distortion can be grouped together by listeners, while other amps with either high or low distortion can be disliked by listeners - the difference being the spectra of distortion.
Of course, if you have a speaker that creates "nasties" on its own, the effect of the amp may be less evident or impossible to discern.
_-_-bear
Surely everyone got the joke. Back when I dreamt of someday becoming an electronics repair tech I met an audio salesman that eventually had to tell me flat out that plain old distortion specs don't mean a whole lot. Of course I couldn't believe it. I had already seen tons of big box store grade receivers rated at <.01% back when A/V specific shops were much more common. At that point I thought that anything audiophile grade had to have less distortion than that. Eventually I fixed that salesman's Accuphase P-300, which was rated at .03%, and it just blew away (Edit: BLEW AWAY) everything I had ever heard at the time. His lack of respect for numbers and insistence about how they tend to leave large parts of the picture undescribed probably had something to do with me never earning an EE degree.
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Ahh. I'm not sure an emoticon would have helped much. I probably should have just saved it. I figure I apologized pretty well.
To make matters worse regarding distortion figures, after so many years I had looked at many circuits and figured I had learned how to make some certain improvements to the P300 circuit. When I got around to proposing them to the owner his reply was, "How will it sound?" :| Of course I had not a definite word to say, and nothing much was ever done to the circuit beyond repairs. It's more than 20 years later and I think I would have some decent answers now, but he has become a semi-pro equipment reviewer and doesn't do any fiddling with the latest gear he gets to hear and none of the stuff he keeps needs it, even though sometimes some of it still measures funny compared to what's achievable if you're just designing for the number.
To make matters worse regarding distortion figures, after so many years I had looked at many circuits and figured I had learned how to make some certain improvements to the P300 circuit. When I got around to proposing them to the owner his reply was, "How will it sound?" :| Of course I had not a definite word to say, and nothing much was ever done to the circuit beyond repairs. It's more than 20 years later and I think I would have some decent answers now, but he has become a semi-pro equipment reviewer and doesn't do any fiddling with the latest gear he gets to hear and none of the stuff he keeps needs it, even though sometimes some of it still measures funny compared to what's achievable if you're just designing for the number.
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THD ... the single number... is an almost completely meaningless specification. There are good amps with measured distortion -- under certain conditions -- well in excess of 1%
The spectrum from which it is derived (what Bear hints at) is much more meaningful but we are still talking about something that is a stimulus far removed from music.
dave
The spectrum from which it is derived (what Bear hints at) is much more meaningful but we are still talking about something that is a stimulus far removed from music.
dave
Andrew, I wasn't looking for an apology, just to explain better for those who are not fluent in idiomatic English...
Dave, not sure if I understand what ur saying...
Oa3, probably your information is not quite right. Music, per se, is a complex waveform that the brain "processes and decodes" into the recognizable form we call music. A pure tone is a different matter. The brain does not decode it in the same way as it does "music" or more importantly "voice."
The way I like to think of it is that the fewer confounding factors (or variations from the original sound), the easier and faster the brain can "decode" the sound and make sense of it.
When there are harmonics present that are not "quite right" we still can hear "music". Right? So, ask yourself what is the difference between a presentation where the "harmonics" are perceived as "natural" (or are technically accurate, without added energies in places where the ear notices it) and one where the harmonics (no matter how low in %) are perceived by he ear as less so??
Why is one presentation different or better than the other??
Or, is it??
_-_-bear
Dave, not sure if I understand what ur saying...
Oa3, probably your information is not quite right. Music, per se, is a complex waveform that the brain "processes and decodes" into the recognizable form we call music. A pure tone is a different matter. The brain does not decode it in the same way as it does "music" or more importantly "voice."
The way I like to think of it is that the fewer confounding factors (or variations from the original sound), the easier and faster the brain can "decode" the sound and make sense of it.
When there are harmonics present that are not "quite right" we still can hear "music". Right? So, ask yourself what is the difference between a presentation where the "harmonics" are perceived as "natural" (or are technically accurate, without added energies in places where the ear notices it) and one where the harmonics (no matter how low in %) are perceived by he ear as less so??
Why is one presentation different or better than the other??
Or, is it??
_-_-bear
Personnaly I had listen to receivers listed with 1%, 0.7% and 0.5% and I can tell that I can tell the difference.
Maybe NOT the TDH itself but something elese needed to be done to achieve that level.
Sure, there are many other measurements that I am looking to when I analize an amplifier BEFORE I go to listen ( so I know if it worth my time)... but one with 1% at nominal power sure won't get my attention.
Maybe NOT the TDH itself but something elese needed to be done to achieve that level.
Sure, there are many other measurements that I am looking to when I analize an amplifier BEFORE I go to listen ( so I know if it worth my time)... but one with 1% at nominal power sure won't get my attention.
Interesting, seems the quest for sonic purity is as elusive as in guitar amps. I thought it might be a little more cut and dry dealing with home audio. lol.
I am thinking of building a little practice amp while I aquire parts for a gainclone project. I am leaning towards this little TDA7377 that I have.
Though the TDA7377 is technicaly a car amp I scavenged it from a PC speaker set, an Altec Lansing 2.1. It was a very nice sounding set for the money. Really there was nothing wrong with it, I just take apart pretty much everthing I own. lol. I am literaly typing this surrounded in what looks like a scrap heap. Awesome.
I bought the set after recomondation from the salesman at Future Shop, I tested it against a few others, hands down it sounded better than the ones 3 times the price. I was surprised because it had these funny down-firing speakers and I never expected much from a little sub. Maybe it was just this particular model because I recomended Altec to my Uncle when he was buying PC speakers however the suround/subwoofer set he bought did not sound as good.
I would love it if you guys had a peek at this Datasheet, maybe give me some feedback, advice or opinions.
Here is a link, hope it works. http://www.audiolabga.com/pdf/TDA7377.pdf
I am thinking of building a little practice amp while I aquire parts for a gainclone project. I am leaning towards this little TDA7377 that I have.
Though the TDA7377 is technicaly a car amp I scavenged it from a PC speaker set, an Altec Lansing 2.1. It was a very nice sounding set for the money. Really there was nothing wrong with it, I just take apart pretty much everthing I own. lol. I am literaly typing this surrounded in what looks like a scrap heap. Awesome.
I bought the set after recomondation from the salesman at Future Shop, I tested it against a few others, hands down it sounded better than the ones 3 times the price. I was surprised because it had these funny down-firing speakers and I never expected much from a little sub. Maybe it was just this particular model because I recomended Altec to my Uncle when he was buying PC speakers however the suround/subwoofer set he bought did not sound as good.
I would love it if you guys had a peek at this Datasheet, maybe give me some feedback, advice or opinions.
Here is a link, hope it works. http://www.audiolabga.com/pdf/TDA7377.pdf
The difference between THD (the single number, what is being talked about) and THD the spectrum chart (needed to see the even & odd order harmonics & higher order distortion components). The former is pretty useless once you collapse the info in the latter into a single number.
dave
You may be fixating on the numbers, but that isn't what is making one sound different from the other. Unless of course, after reading the numbers the order of preference is already lodged in your brain.
dave
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