Influence of power amplifier output coil to frequency response

[jcx]

cable properties:

http://www.passlabs.com/pdfs/articles/spkrcabl.pdf


audible frequency response variation thresholds:

ABX Amplitude vs. Frequency Matching Criteria

 

[Conrad Hoffman]

A couple things- the usual arrangement is not only an output inductor, but a load of maybe 0.1uF in series with 10 ohms to ground. That alone should mess things up nicely, but most amps need it for maximum stability. Then there's the whole issue of modeling. I guarantee there are strays you haven't accounted for. You really have to verify the model with some physical measurements to have any faith in it. The imperfections we're talking about here (at frequencies I haven't heard in decades) are well known, as are the causes. It's nearly impossible to get flat response at the speaker terminals down in the fractional dB range; it might be possible with driven sense lines but the stability issues would be tenfold!

 

[PMA]

You really have to verify the model with some physical measurements to have any faith in it.

But I did. I first measured the issue and then started with simulations - both correspond very well. An there is a Zobel at amplifier output. The last plots show real amplifier simulations.

Once the simulation fits to measured result, it is far easier to make stepping of component values etc. in simulation, as one would need hundreds of measurements to get the same. Then, the final results are verified by measurements - that's a standard practice. I am not a 'simulation guy only' or 'armchair designer' at all. I use the tools when they are effective.

Regards,