A truly passive line conditioner like the Foundation Research LC-1 or LC-2 should never rob a component of its dynamics since a truly passive LC draws no current to itself. I'm only aware of one potential opportunity where a FR LC might rob some dynamics and that's if you exceed its current rating. Like connecting the LC-1 (10 amp current capable) to a higher-powered higher-current-drawing amplifier that exceeds 10 amps.
The LC-1 as I recall was a 10 amp current capable unit intended for front-end components like a CDP or pre-amp and the LC-2 was a 20 amp current capable unit for most amplifiers. At one point in time I owned a McCormick DNA-2 Limited Anniversary Edition amp and then a McCormick DNA-2 Revision A amp both of which were plugged into an LC-2 via a 20-amp IEC connector. These are 20 amp amplifiers were rated at 350wpc into 8 ohm loads or 1200wpc into 2ohm loads and dynamics never suffered so long as they had their own dedicated circuit / line from the service panel. Their replacement models, the LC-10 and LC-100 were 10 amp and 100 amp current capable where the LC-100 at least in theory was intended for use with the largest current drawing amplifiers in the world.
Foundation Research makes superior line conditioners in a world where inferior line conditioners that either do nothing or worse induce their own sonic harm reign supreme. As stated by a few others Foundation Research line conditioners are passive, dedicated, and bi-directional filtering. Oh, and they do what few other line conditioners can do, which is actually cleanse, purify, filter, and/or condition the universally noisy AC coming in from the street.
To the best of my knowledge every reviewer I'm aware of that auditioned the LC-1's and LC-2's purchased the review samples. Again, to the best of my knowledge, for years the only line conditioners superior to the LC-1's and 2's were the LC-10's and LC-100's of which I also owned. How much better? I'd estimate 2 to 3 times better than the LC-1's and 2's.
Foundation Research went out of business about 6 years ago, maybe more. I finally off-loaded my last Foundation Research LC a little more than 2 years ago because I had a chance to audition the Jena Labs THE Two line conditioners and they are a bit more musical than the Foundation Research LC's.
I'm unaware of any power cable that can come close to providing the potential leap in musicality that the Foundation Research units can provide.
In fact, you may only be hearing a small percentage of what the Foundation Research unit is capable of. At the FR LC's AC plug try opening up the AC plug and disengage the grounding wire and you just might hear quite a leap in its performance. If per chance you have one of my old LC-1's, then perhaps the ground has already been lifted. Yeah, I know what I'm suggesting. I've owned the Foundation Research LC's for 16 years - one for every component in my playback system and for 16 years all my FR LC's were ungrounded and for good performance reasons. Moreover, after taking possession of my LC-10's and LC-100's their performance literally doubled when I swapped in cryogenically-treated fuses, Furutech (also cryo-treated by Furutech) AC plugs ($45 each) and IEC connectors ($35 each). Replaced all these items at the same time and the improvement was fabulous after these items fully burned in at the same time with 4 FR line conditioners.
So with your existing FR LC-1, I see you may be lacking performance for several reasons:
1. Most likely your LC-1 is still grounded.
2. To really reap the full benefits of the FR LC's, you really need to have one FR LC for each component.
3. If your LC-1 is stock, then you should consider installing a cryo-treated fuse and replace the AC plug and IEC connector with Furutech models (all Furutech electrical products are cryo-treated).
Another thing you might try is if you have several analog front-end components say a turntable, a phono amp, and a pre-amp, you could connect your LC-1 to a power center or power strip and then plug in multiple front-end analog source components so that they all receive the same / similar sonic benefits from a single LC-1. You could connect a digital source into the power strip also but you may notice a bit of digital glaze being being shared with the other components sharing the same power strip plugged into the LC-1.
Anyway, you've got yourself a little treasure in the LC-1 even though its technology is perhaps 20 years or older now. If you cannot find a suitable replacement, you should definitely keep it because again, I'm unaware of any power cable able to match the musicality of a superior line conditioner of which the LC-1 is.