Cable "burning": Real or VooDoo ???

Sean - If I were a designer with a design that was as technically perfect as the state of the art would allow and yet some audiophiles complained that it "wasn't right" or wasn't musical or wasn't lifelike here's what I would think about trying.

First, I would consider injecting noise into the output. Now, no one likes noise during the quite passages so I would make it a smart noise injector that varied its output with with volumn and perhaps energy in the high frequencies. The noise spectrum would probably not have lower frequencies - one would have to experiment. The circuit would recognize testing conditions and not operate. I suspect that noise gives music an airy lifelike quality that many like.

Next, I would lower the damping factor. As the damping factor lowers the amplifier begins to get involved in the music. Lower damping factor may or may not have a pleasant effect, so, a damping factor control knob could be an attractive feature. From a marketing standpoint I would give it a name something like "Voicing".

I would also experiment with increased harmonic distortion. I don't know if it is possible to increase lower harmonic distortion without increasing itermodulation distortion. IM creates unnatural frequencies and is always unpleasant. Harmonic distortion on the other hand is what music is all about. All musical instruments owe their sonic character to harmonic distortion of the fundamental. Just the right kind of harmonic distortion could, I suppose, make an amplifier seem more musical.

Stevenmj: I believe that most of what you mention has already been used in past and present designs (both tube and SS). You may want to go through the Tweaker's Asylum at AA and see what you can find on these concepts. I suspect that the "air" that you mention is really a type of re-verb that is most noticeable in quite a few tube designs which incorporate low to zero feedback and which may also stem from the types of tubes used in the designs (many small signal tubes types are somewhat microphonic, even those that test well, and may add to this sense of air/reverb). There are also quite a few tube designs in which you can "dial in" the feedback, though I am not aware of any SS designs with this feature off hand. Once again I am not a technical person, just your average theorist.

Stevenj, I cannot tell if your post is in jest, or you are sincere. If you are suggesting that lowering and raising the damping factor with a switch is a joke, I can assure you that it is not.

Controlling an amplifiers damping factor is not novel. The Wolcott Presence amplifiers have had this feature for two years. The user has easy access to a toggle switch for both high and low position, and a rotary knob that adjusts within each range. Adjustment of these controls provides performance changes that are not only easy to hear, but at the discretion of the listener.

The man who invented this product is an engineer who values specifications, but is also aware that the reproduction of music is an art as well. If it is of any interest to you, the switch changes the positive control feedback voltage internally, without affecting the load to the output transformer.

albert, i have a suspicion that stevemj's post *was*, in fact, in jest. ironic, that, as you show, it's actually what smart designers *do*. seems to me they know something *isn't* "technically perfect", as stevemj purports, if it in fact cannot accurately portray *the real event* of live music.

regards, doug s.

doug - I wasn't jesting. I was just musing. I'm not up to date on amplifier designs. So, it is interesting to hear that some of what I mentioned has been tried. There was an amplifier some time ago called "Ampzilla". It sounded different. The trick that amp's designer had used was to set the damping factor to one. Typically, this will increase the low end. With the advent of cheap powerful processors there maybe a lot of interesting possibilities. The processor looking at the music and dynamically fiddling with the an amplifiers characteristics. I'm gonna think about this a little.