Posted by PakProtector [ 205.188.116.67 ] on December 14, 2005 at 20:18:47:

In Reply to: Re: measuring grid chokes posted by MQracing on December 14, 2005 at 19:36:48:

hey-Hey!!!,
Since there is no means of measuring how good a part will sound in-circuit, we're stuck measuring single parameters, or groups of them.

With these measurments, it is possible to examine circuit behaviour, or at least make predictions based on well-researched guesses. Once a circuit has the device installed, we can see how it sounds. Since no reasonable measurements exists to quantify what we think we hear, we're stuck with single parameters or groups of parameters to measure.

I have yet to see a group agree on why a SE amp sounds the way it does...yet there are plenty who'd refuse to classify the amp from the un-favoured topology as listenable. Only one can be best, and that sort of thing.

Turns out there *ARE* a lot of characteristics that can be measured which shed light into how an amp should sound, and where its bandwidth will start and stop.

In the grid choke example, to simplify, it is operating as a low DC/high AC impedance device. Seems reasonable that its impedance across the traditional audio spectrum would be of interest. Since it is to me, and a few others, I've proposed not only to measure, but to describe the methods and equipment used to measure. The numbers are what they are, and if anybody wants to suggest ways of analyzing the data, or proposing a detailed method to gather it, I'm all ears.

As to the rest of the suggestions on my design practices, I don't recall ever saying that any single parameter should be used in the design stage. Matter of fact, I have actually taken just the opposite aproach in discussions about PS DCR for examle.

In God we trust, all others bring data!
cheers,
Douglas

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