I'm cheating, but have a look here -
http://www.vinylengine.com/turntable...hp?f=19&t=6674
and follow the links..
It's usually been the thing to alter the capacitance as seen by the cartridge, 'cos it's easy to do. However, despite the standard load being 47K, some cartridges do seem to need either higher (68K approx) or lower if they're peaky like some old Deccas (30 - 40K), to fine tune the hf response.
I have no knowledge of the Precept at all I'm afraid. Some of the older AT VM based models had a falling treble and increasing the impedance and/or capacitive loading if possible may well lift the treble a tad. Other modern AT's are trebly in comparison (120/440 models) to make them more "CD like" in balance, especially with japanese vinyl pressings, which seemingly balance them out nicely.
Can't be more specific I'm afraid. I love the AT120E I have, used in a low mass and not too rigid arm (oh alright, a Garrard AP76
) and I'm sure I'd also love the AT440MLa as long as azimuth and VTA is adjustable to fine tune the line contact tip.
Any help?
P.S. I for one, found the Grado prestige range to be a bit dull, the dullness getting worse as the models went from black to gold the resonance "sparkle" being refined out as one goes up the range. Grado have recently? announced a "1" replacement range, with slightly reduced tip mass and less turns on the internal coils. I have no real idea, but I wonder if the reduced moving mass might be a slightly shorter cantilever to increase generator movement to counteract the reduced coil efficiency, but the reduced coil turns may actually aid HF response and loading requirements. Purely amateurish guesswork, but good for them if there's a genuine improvement here