Total Harmonic Distortion

[SpreadinButter]

What is 1% total harmonic distortion, is it an issue, or does that mean if I really crank the amp it will start to distort?

[Nick Kay]

That's simply how much distortion is present in the signal at that power level. Normal ears start hearing distortion on plain sine waves at about 0.5% THD, but on more complex waveforms, that figure can jump up to more than 2% THD. It's also frequency dependent. Distortion at low frequencies is more difficult to hear than distortion at higher frequencies.

That being said, if that amp was putting out that much power, that's how much distortion would be in the signal (ie: an unnoticeable amount for most people on complex waveforms). If you want a perfectly immaculate, clean signal with headroom to spare, expect a bit less output than the amp is rated for at 1% THD.

[hbarcat]

Total Harmonic Distortion is a standard way of measuring the amount of deviation in an audio amplifier of a reproduced waveform from the original waveform. The measurement of THD is not a perfect description of the quality of sound you hear because the reality is more complex than this, but percent THD is a good place to start.

In general, 0.1% THD is considered acceptably low and amps are often rated for output at this level (along with other complicating factors). As power output increases to the limit of what the amplifier can produce, the THD increases exponentially. A THD of 1% is audible and at the power level where this occurs it is often considered to be the practical power limit of the amp.

[SpreadinButter]

Originally Posted by hbarcat

Total Harmonic Distortion is a standard way of measuring the amount of deviation in an audio amplifier of a reproduced waveform from the original waveform. The measurement of THD is not a perfect description of the quality of sound you hear because the reality is more complex than this, but percent THD is a good place to start.

In general, 0.1% THD is considered acceptably low and amps are often rated for output at this level (along with other complicating factors). As power output increases to the limit of what the amplifier can produce, the THD increases exponentially. A THD of 1% is audible and at the power level where this occurs it is often considered to be the practical power limit of the amp.

So basically if I push the amp to its peak limit it will start to distort? Makes sense.

[JimmyM]

Originally Posted by SpreadinButter

So basically if I push the amp to its peak limit it will start to distort? Makes sense.

Not to its peak limit. Your amp will have lots more power past its clean power. Pushing it to its RMS limit and beyond will start distortion.