Hi, Tom. I'd like to qualify my post here that I recently became a dealer for Nuforce, Foundation Research, Star Sound, as well as my own custom racking systems employing the same 'resonance energy transfer' methodology as Star Sound for their Sistrum racks. But I've been using the Foundation Research line conditioners for the last 5 years and Star Sound Audio Points for the last 3 years.
I'm of the camp that thinks every structure wired for electricity has dirty/noisy AC coming in from the street. Some to a worse degree than others but all would benefit from 'proper' line conditioning.
There are several reasons I can think that your experiences with line conditioning were negative (and you are not alone with your experience):
1. Just like any other component, there are some to many line conditioners that simply are not worth owning. They induce serious current limitations and/or induce their own sonic harm. I'm thinking of a very popular mfg'er in particular but there are others. Case in point, I sold a pair of Nuforce amps to a customer and shortly thereafter, I brought over my Foundation Research dedicated line conditioners for him to try after we installed the amps. His system was quite fatiguing and after about 20 minutues of listening, I asked to install the new line conditioners. His was a popular name brand. Swapping out the old and installing the Foundation Research was a very apparent improvement. Before we installed another for his APL modified Denon 3910, I asked him to remove the popular line conditioner and simply plug the APL straight into the wall. We both agreed his system sounded better without the old line conditioner as it was easily a more pristine and musical improvement just by removing his old (new) line conditioner. Then we installed an LC-1 to the APL for far greater improvements. He immediately went out to Audiogon and found 4 used Foundation Research line conditioners and bought them.
2. There is a small percentage of component mfg'ers who incorporate their own flavor of AC filtering. For example AYRE employs what they call AYRE conditioners where they insert numerous filters (at strategic points in the frequency spectrum) to address certain offending frequencies. But again there are other manufacturers and other methodologies. If one owns components of this nature, it is always detremental to double up on line conditioning, especially when employing different methodologies.
3. Every so often, very rare in fact, a component's power supply (usually an amplifier), has so much unusual current draw (even though it's power rating may not be very high) that the associated line conditioner simply cannot meet the demand. The Pass Labs X-250 comes to mind. Not the 350, only the 250.
Tom, I know how committed you are to proper vibration control for your components and racks and speakers and I think you know how committed I am also.
I can say with confidence that the sonic improvements of employing 'proper' line conditioning of all components is easily equal to or even better than employing 'proper' vibration control throughout one's entire system.
For example, negative sibilance is most often introduced as a result of dirty AC (when it's not a part of the recording itself via microphones, etc.), a lowered noise floor to the point where one can hear little nuances never before heard, are just a few of the things that proper vibration control typically do not/cannot address or improve.
Of course there are other improvements that proper line conditioning shares with proper vibration control such as deeper, tighter, more well-defined bass, extended highs, greater dynamic contrasts, enhanced 3-D soundstage, pin-point imaging, et al.
And if you have any doubts contact me and I'd be happy to send something your way to audition to remove any doubts.
-John
