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<blockquote data-quote="GordonW" data-source="post: 2247882" data-attributes="member: 568981">Dismissing tube amps as &quot;higher distortion&quot; and &quot;colored&quot; is a simplistic argument. And as such, it&#039;s frequently false.When comparing two amps, there&#039;s a very useful test called &quot;distortion spectrum test&quot;. Basically, it&#039;s NOT only HOW MUCH distortion, it&#039;s HOW MANY harmonics the distortion typically shows up in.The human ear is very tolerant of low-order harmonics (ie, second, third, fourth harmonics)... but higher order harmonics (8th, 9th, 10th, and so on) can be heard/sensed in VERY SMALL quantities... and are usually regarded as a &quot;harsh&quot; or &quot;gritty&quot; sound.While tube amps have more second and third harmonic distortion, the distortion spectrum goes VERY RAPIDLY to zero. It&#039;s rare to have significant higher harmonics present, at anything other than HARD CLIPPING. OTOH, there&#039;s LOTS of solid state amps (fortunately, not as much as it was, even 5 to 10 years ago) that exhibit SIGNIFICANT, AUDIBLE amounts of higher harmonics, EVEN AT LOW LISTENING LEVELS, due to non-linearities in the transistors themselves that CANNOT be completely corrected by feedback. Feedback is good at correcting lower harmonics (lower frequency, less bandwidth required by the feedback circuit) than they are at correcting higher harmonics (where the frequencies sometimes EXCEED the bandwidth that the feedback loop can correct, due to time delays in the return path).As I mentioned, there ARE better semiconductors now... and REALLY GOOD solid state designs (high-end stuff, for the most part) can be VERY clean/transparent/smooth sounding. But MANY amp designs out there (especially on mid-priced stuff) are based on older technology... and still have some of the same problems...So, don&#039;t fall into the trap of &quot;it measures better, it MUST sound better&quot;. You&#039;ve gotta be careful of WHAT they&#039;re measuring, and HOW they&#039;re measuring it!!Regards,Gordon.</blockquote>

[QUOTE="GordonW, post: 2247882, member: 568981"] Dismissing tube amps as "higher distortion" and "colored" is a simplistic argument. And as such, it's frequently false. When comparing two amps, there's a very useful test called "distortion spectrum test". Basically, it's NOT only HOW MUCH distortion, it's HOW MANY harmonics the distortion typically shows up in. The human ear is very tolerant of low-order harmonics (ie, second, third, fourth harmonics)... but higher order harmonics (8th, 9th, 10th, and so on) can be heard/sensed in VERY SMALL quantities... and are usually regarded as a "harsh" or "gritty" sound. While tube amps have more second and third harmonic distortion, the distortion spectrum goes VERY RAPIDLY to zero. It's rare to have significant higher harmonics present, at anything other than HARD CLIPPING. OTOH, there's LOTS of solid state amps (fortunately, not as much as it was, even 5 to 10 years ago) that exhibit SIGNIFICANT, AUDIBLE amounts of higher harmonics, EVEN AT LOW LISTENING LEVELS, due to non-linearities in the transistors themselves that CANNOT be completely corrected by feedback. Feedback is good at correcting lower harmonics (lower frequency, less bandwidth required by the feedback circuit) than they are at correcting higher harmonics (where the frequencies sometimes EXCEED the bandwidth that the feedback loop can correct, due to time delays in the return path). As I mentioned, there ARE better semiconductors now... and REALLY GOOD solid state designs (high-end stuff, for the most part) can be VERY clean/transparent/smooth sounding. But MANY amp designs out there (especially on mid-priced stuff) are based on older technology... and still have some of the same problems... So, don't fall into the trap of "it measures better, it MUST sound better". You've gotta be careful of WHAT they're measuring, and HOW they're measuring it!! Regards, Gordon. [/QUOTE]

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