Liguy: It's not only a matter of response time, it's a matter of ringing. Faster diodes produce less ringing and this can be seen as a reduction in harmonic content in the power supply. In case you haven't noticed, JA has recently measured quite a few amps that suffer from a measurably high harmonic content coming out of the rails. The use of higher quality rectifiers that are faster and produce less ringing would minimize / negate that problem. This is the reason that some folks think that Schottky's and other "fast" diodes "lean out" the device that they are installed in. That is, they get rid of the artificial "warmth" that the slow, ringing diodes contribute to the sonics of the device they were installed in.
As a case in point, Nelson Pass has never been a fan of "fast" rectifiers. Then again, most of his amps have never been known as being "bass monsters" either. As such, installing "fast" rectifiers into his older designs resulted in a presentation that he thought was too lean sounding, hence he didn't recommend that mod. He has recently taken a liking to these devices and his latest amps are making use of them. My guess is that he's found a way of taking advantage of them while retaining the sonic signature that he prefers.
This is something that everyone should think about. That is, many components are voiced based on specific system conditions. If the component was voiced with "dirty" AC coming into it, removing all of the grunge may leave you with a different sound ( for better or worse ). On the other hand, running a device on dirty AC that was voiced using highly filtered AC may not deliver the sonics that the unit is capable of providing. While "clean" AC should always work best, there are so many ways to "clean" AC and so many different component designs, it's quite possible that some combo's may not work that well together. If in doubt, contact the manufacturer and see what they say. Good quality gear already has quite a bit of filtering built into it and would be voiced accordingly. Sean
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