Sonic improvement with Threshold FET 9 refurb?


Hi All,
In a recent post I was asking if anyone knew of an affordable ($1200 or so) sonic step up from my ARC SP14 preamp since a threshold FET 9 I had recently aquired from a fellow Agoner did not, to my ears. sound quite as transparent and holographic as the SP14. Very,very nice, yes, but not a step up. I didn't get any suggestions other than to upgrade the SP14 electronics and a comment that there was probably no affordable step up.
Anyway, after re-reviewing the glowing write-ups on the FET 9, I'm wondering if, despite its nearly pristine condition inside and out, my example might be a bit "tired". I realize that there is significant controversy about the need for capacitor replacement and or power supply upgrades and don't want to spend a lot of money trying to fix somethhing that is really working as well as it can, but am wondering if this might be sonically worthwhile. I would greatly appreciate hearing from anyone who has actual experience with this or a parallel scenario.
Thanks!
drjay
FWIW, as far as I can tell the differences between the FET 10 and the FET 10e is that the e series has a beefier external power supply with completely removable (and possibly upgradable?) umbilical cord, a set of XLR inputs and outputs (though neither set is truly differentially balanced), slightly different control options and layout, with different knobs and other cosmetics. I would think that the 9 series would have similar differences, and that a standard FET with e series power supply, would be at the very least comparable to a "full blown" e series.
I believe the SP-14 is somewhat similar to the SP-9. Both of these units had crosstalk issues. As frequency went up, crosstalk went up. This caused a problem with the image to some extent. It manifested itself as a whitish curtain between instruments in space and a lack of silence between them. I doubt the FET9 had the same issues as the SP-14 but remember, both units use older FET technology.
FWIW, here's a comparison of a newer higher end model Threshold FET 10 with an older model Audio Research SP 11 and a Klyne.
http://www.stereophile.com/content/threshold-fet-10-preamplifier-page-2
The SP-11 although an older design is also a very different design from the SP-14....
Hi Everybody,
A big thanks to all the folks who have helped me out on this one. I talked at length to Jon Soderberg yesterday evening and he said that I would get a significant improvement with a power supply which he makes which is an FET9e equivalent and with an upgrade recapping of the main unit. So, off it will go to him. I'll report on the results when it gets back to me in a few weeks, since there may be interest in the effects for others who have similar situations.
Thanks again,
Jay