I just want to add that Japanese audio companies like Furutech, Air Tight, TOAC, Nanotec Systems, and of course Harmonix have a very serious attitude into researching in areas where many are not spending the time or resources. They really drill down on whatever innovative ideas that happens to flash across, and at times meaningful products comes up. I think there is sometime to do with the character and culture of Japanese.
I did not try the PC-2, but I did try the RD-2 (the de-magnetiser), I tried NanoTec Systems "Disc Re-Conditioner" or Optical Disc Finaliser, and some of the novel isolation blocks from Air Tight (graphite) and isolation platforms from TOAC.
I would not care what others think but in my case they do make a difference in most cases - to my ears. Mostly on the positive side, but some are not as prominent as the others. I also owned the Lathe (disc cutter) - a pretty popular product from Germany and a lot of support in Europe, and are pretty happy with what it does.
Environmental factors also play a part - the quality of the systems, character along the audio chain, listening environment, type of music, quality of recording, etc. all can contribute to our listening impressions.
Comparatively speaking, tweaks from North America appears to be less convincing - I tried the pebbles, the magical little clock, and even Audience Illuminator CD treatment. The only tweak that really have a consistent and positive effect is the ProGold treatment and Quick Silver Gold treatment on contacts.
There are new tweaks coming from China - a tiny disc that can treat CDs at quantum level, some special wood that can add harmony between different frequencies in your room...... and they also are not convincing - to me at least, based on my own experience.
My view is therefore, as in all aspects of audios, there is no generalisation on these tweaks. Calling them all work, or all won't, would mean we are missing a lot of fun.
I post just to share my personal experience. I am not trying to convince anyone things work or don't work.
Peace to all.
The tweaks that i tested are fibration feet under the cdplayer and they had a significant improvement on the sound and better cables, wich also had a huge impact on sound.
In general for tweaks: at your own risk. Some work, some don't. it's to us to find out wich really work and wich don't. Shooting them all since people think nothing works is just their loss. I gained considderable, audible improvements using these tweaks i mentioned above (cables and fibration reduction under the cdplayer).
The tweak that brought the biggest improvement was ofcourse totally modding the amp, if you still can speak of a tweak replacing that much components for high end components.