Re: Tubes in Pre-amps: your expertise and honest opinion.

["Jon Southwood" <jsouthwood@gmail.com>]

Sorry, Rick, but this isn't quite right. The 6th partial is an octave above the 3rd partial, not another repeat of the octaves of the fundamental. In other words, it is two octaves plus a 5th above the fundamental. The even partials are all octave shifts of odd (or other even) partials.

Because of this, if only the even partials are present (with the addition of the single odd-numbered partial in the form of the fundamental), it takes us more space to get to the more dissonant partials. In other words, if the 7th partial is the first that we'd consider a dissonant contributor (debatable), then instead of that partial being two octaves and a minor 7th (roughly) above the fundamental, our evens-only set doesn't contribute it until another octave higher, so it's that much farther away from the fundamental which further softens the potential dissonant impact. The 9th partial (roughly 3 octaves and a major 2nd) doesn't contribute until yet another octave higher.

The more octaves that separate a partial from its fundamental, the softer its 'dissonant' contribution. This will hold whether it's a case of "only even numbered partials are present" or "even numbered partials are emphasized."

Cheers,

Jon Southwood

On 1/2/07, RICK WALKER <looppool@cruzio.com> wrote:

Dear Margaret,


If we take just the first harmonics in this natural series we
get

F             H1                  H2                    H3
H4              H5...........etc.
1st           2nd                3rd                    4th
5th              6th
Fund       Octave        Oct+5th         next Octave        next+3rd
next Octave

As you can see,  the even harmonics are all octaves.
Because of this,  they are consonant, harmonically,  with the origial
Fundamental frequency and
sound smoother and more 'harmonious' to our ears.