Amp ICs -- What are they? (1 Viewer)

[Mark Austin]

Ken,

Wow again. Very interesting post.

The crux of this whole debate is really this (IMHO) : we need to come up with accurate and repeatable causal relationships for all the things which our ears tell us and the oscilloscope does not.

IMO, we can never reach that goal. First, each individual brain's interpretation of what sound is good, bad or indifferent, would nearly be impossible to bring to a meaningful number from person to person. Next is that even the shape of our ears has a direct influence on how the sound information is realyed to the brain. Can you imagine the variables?

I agree with everything you have said. Great stuff keep it up.

 

[brucek]

Guys,

It certainly wasn't my intent to offend anyone in my post. The thread starter asked for basic technical information on interconnect cables and interfaces. Technical information for a reader without the appropriate background usually requires interpretation as to the significance of the information. I wasn't attempting to mislead. I admit the post was written in haste and I didn't really take time to elaborate on any of the conclusions, particularly in the area of cable capacitance and its effect in relation to preamp/power amp impedance's. I didn't feel the original poster was interested in these boring details, so I gave some quick (maybe too quick) information and conclusions.

But, as I discussed with Mark Austin last month in a post where he took exception to the word "significance" that I had used several times, (and I'm repeating myself here), this interpretation of "significance" is a standard engineering tool for drawing conclusions. It's standard practice to look at all the facts and eliminate low order effects, and then try to make an informed conclusion with what's left. This is how many equations are derived. You throw out or ignore effects that have no real significance or that are miniscule in relation to another larger effect that is overwhelming a situation. I suppose it is debatable whether the conclusions drawn were opinion or fact.

For example, if I find that an interconnect cable exhibits an inductance of 0.5microhenry and so at worst case 20Khz solves to a series impedance of 0.062 ohms, then in relation to the amplifiers load impedance of 50,000 ohms, I am allowed to draw the obvious conclusion that the inductance is not worth considering in an interconnect because it's an attenuation of 0.00001dB and it's not significant. I don't feel this is really imparting my opinion, nor is it a value judgement, it's a simple fact. I could say it was my opinion that 100 out of 100 technical people would draw the same conclusion as I do on this point, so I take license to express the conclusion as fact.

As I've already discussed with Mark before (and the very thing he objects to here with respect to technical truths and misleading effects), is that cable manufacturers and their associated web sites have been able to effectively use science to their advantage to completely ignore the "significance" rule. For example, they will apply the effects of electromagnetic phenomena for current propagation through a conductor to their cables. A rather creative job is done discussing current bunching, skin effect and frequency blurring when all these effects only apply at high frequencies. I'm referring to radio frequencies (RF) in the hundreds of mehahertz. What do they have to do with audio? Can I say absolutely nothing? No, but can I say that the effects are so ridiculously 'insignificant" that they can be ignored? Yes, of course I can.

Either way, I gave out some basic information and so everyone is allowed to do the same. It can completely disagree with what I say. That's what forums are for.

brucek