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5% THD to .000 THD SOUND

I was searching the amplifiers available and noticed quite a big difference in THD specs from model to model. Example.. One of the best amplifiers Kondo Audio Note $150k Kagura has 5% THD and by reviewers definition sounds like an amazing amplifier. Now compare $ 30k  Devialet with the lowest 0.000% THD on the planet. Both at the opposite end of design yet both sound amazing.. according to reviewers, I havn t heard either. SN/R  133 by Devialet and a lot less by Kagura. I realize an amplifiers sound can t be based by Specs alone.  If the specifications are not that important to the sound, why list them? They must be a way of determining sound, quality, and system synergy of an amplifier? A whole lot of amplifiers purchased on the net haven t been heard before and I believe the decision to purchase is made by reviewers point of view, specifications and word of mouth of other owners and buyers pocket book. By looking at specs of Devialet and NOT knowing the prices of Kagura and Devialet I would of gone with the Devialet just based on specs alone for the impression of it being a  great sounding amplifier.  Ive read other discussions on forum and cant quite get a handle on why BOTH amplifiers sound great. I thought High THD was a bad thing..
derrickengineer
onhwy61's avatar
onhwy61
5,229 posts
 
Static THD measurements alone won't tell you how an amplifier will sounds when driving a loudspeaker.  It's far more complex.
erik_squires
16,134 posts
 
Specs are important to making sure you aren't getting ripped off. It's easy to rate a 35 Watt amplifier as a 100 Watt amplifier if you don't mind 10% distortion.  Used to happen very frequently.

Accuracy is also not necessarily what you buy. You buy amplifiers that make you feel good, whether it's in how they reproduce music, hos sexy the tubes glow, or how difficult their name is to pronounce.

THD is a bad thing, but it's not the only bad thing.  You can make almost any solid state amplifier have vanishingly low distortion if you raise the feedback enough.

Einstein said that not everything that matters is measured, and not everything that is measured matters.  We are still very much in that place when it comes to electronics. There's a separate thread going on about Hafler.  Measured great, boring and lacking in dynamics as you could possibly want. I don't know why. I'm sure with enough time and effort we could discover this, but no one has put in the time yet.

One criticism of amplifier measurements is also that we don't often measure linearity or have enough of a measure to explain how they would work with a particular speaker. That is, we can measure speakers, and we can measure amplifiers, but we don't have really good stats for predicting how they will work as a system, and how to correlate this to perceived behavior.

So, always listen for yourself, and spend the least amount of money you can to make yourself happy.

Best,


Erik
geoffkait's avatar
geoffkait
23,365 posts
 
Let’s see...if 5% THD sounds better than 0.005% THD does that mean 10% THD might sound better than 5% THD? Sign me up!
gs5556
1,235 posts
 
You answered your own question -- the specs steered you into spending money towards the advertised distortion spec. Marketing strikes again.

THD specs can be misleading if they are taken at one frequency at a very low power output. THD, in general, changes as frequency and power output changes. I don't see how anything can be a flat zero distortion and if there is I can't see how that would sound any better than 0.01% at full load -- which is way below the threshold of hearing.

Tube amps generate second order harmonic distortion which is one octave above the fundamental, so both frequencies cannot combine and interfere with the signal from the source. This is like having the same instrument playing two separate tones in unison an octave apart, resulting what appears to be a warmer, fuller sound. But it's still distortion even though it can sound great.
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