But, depending upon the shade of pink your pink noise is (or if you are using white noise whose white kelvin value is on the low-is side) you might be able to just barely hear a difference if the 1dB attenuation at 20Hz is switched in and out as in a A-B comparison.

Assuming this attenuation at 20Hz is caused by the input coupling cap, adding another one in parallel (leaving the original one in place) will move the -1DB point below 20Hz. Plus, you can select your audiophile capacitor of choice. The additional cap can be easily removed in case you want to return the amp to it's stock condidtion.

Noting the comment about the high frequencies starting a rolloff at 3KHz and being 0.3 dB down at 20KHz, if this rolloff is caused by a bessel type low pass filer, then the designer is after superior (less) phase shift in the passband at the (slight) expense of a somewhat lower in frequency start of the amplitude rollof, a design approach that I like.

Paul

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the 1derful1

[This message has been edited by Paul J. Stiles (edited June 22, 2003).]