Prefer second or third order?

[Colin]

Tubes or solid-state?

Maybe the tubes or solid-state debate will never end: at least what Nelson Pass says indicates it might not:

In an e-mail long since deleted, Nelson once shared how based on his experience at Pass Labs, there's a nearly equal number of listeners who favor 2nd-order or 3rd-order harmonic distortion. One sounds sharper, more articulate, precise, fast and PRatty; the other is warmer, more relaxed, bloomier and somewhat romantic.

http://www.6moons.com/audioreviews/firstwatt2/f2.html

Pass F2 solid-state amplifier with 2nd order HD

I notice that simple little amps particularly excel at simple musical material but reveal their weakness in complex orchestral passages at higher volumes. It seems that the 3rd order amps do the complex material a little better, but then they usually measure better so there is less overt IM."

even very good valve amps find themselves on the short end of one particular stick. That unfair advantage is called control (or cone acceleration if you want to get fancy.) It's something devotees of unconditionally stable load-invariant muscle amps have known all along. These transconductance amps achieve the same kind of über control with minimalist circuits and a bare minimum of output devices. It's rock-hard muscle without the beef cake physique but sting-like-bee speed. This control translates as articulation and crispness even at low levels and with albums where the lead vocalist is miked such as to be somewhat recessed and overpowered by the band. Without moving such singers forward or "making them louder", the upped definition and sculpting of each note makes it appear as though the singer was louder just because it's easier to distinguish him or her from the surroundings. It's a bit like the difference between an actively driven speaker and the same speaker with a passive crossover.

[PrestonTom]

Colin,

I was under the impression that the issue was whether the distortion was even or odd harmonic distortion. And that one difference between tube vs solid state was which type of distortion they exhibited. One description is that an even harmonic series has more of "chime" quality (in fact, the majority of physical/acoustic devices tend to have odd harmonic series). This, in part, is what makes a chime have a different quality or timbre.

Anyhow, I am from the old school and believe that the goal is not to have any distortion during the reproduction. Quite frankly, this is what excites me about high efficiency stystems like horn loaded designs.

Even with a modest size amp driving a loaded/horn cabinet it should be quite difficult to clip or distort the signal. These cabinets are such an easy load for an amp. They are efficient/sensitive and the impedance is fairly stable and does not drop too low (does not require high currnet output for the transients.

Maybe the levels I listen to are not at a deafening level.

-Tom

[Colin]

true, but tube lovers say that even order distortion is more natural, turns out the cillia in our ears create even order distortion, so some distortion sounds more natural...

[boom3]

I think if you are pushing any amp to the point where distortion is audible on a repeatable basis, it matters not whether it is second or third harmonics. With Heritage speakers, if your amp is near, or at, clipping, you either have a chronically undersized amp, or, your SPL is dangerously high. I presume we all know that amps in clipping tend to blow tweeters, and maybe other drivers? I'd say with efficient speakers it should be a non-issue. The main component of "tube sound" is the low damping factor compared to solid state. Some people like that big, bloomy sound, I prefer tighter bass.

[Colin]

1. Amplifier distortion is not just when clipping. THD above 1% adds IM distortion, which is audible at lower volumes. So it does matter whtehr it is second or third order distortion.

2. The main component of "tube sound" is not the low damping factor compared to solid state. It is the second order distortion. I too prefer the tighter bass. That is why I sometimes let my sub intrude up into the mid bass range to give the tubes a gentle nudge.