I currently have a ARC ph-5 phono stage

Sorry...in case the link above does not work, here it is again: http://www.tonepublications.com/MAGPDF/TA_037.pdf

Review of PH6 from The Audio Beat: http://www.theaudiobeat.com/equipment/audio_research_ph6.htm

Link to a review of PH6 from Hifi World here: http://www.audioaficionado.org/audio-research/9484-review-arcs-ph6-phono-pre-hifi-world.html

Yes the PH-6 is a nice improvement from the PH-5. I own the PH-6 and a friend owns the PH-5. We have compared them side-by-side.

The PH-6 provides a much smoother, more refined sound versus the PH-5 with a deeper and better articulated soundstage. Lower noise floor, blacker background.

The PH-5 is a great phono stage. ARC has raised the bar considerably with the PH-6.

Anyone compare the PH-7 to the PH-6 or PH-8?

Why not just take your PH5 to the dealer who claims the PH6 is "smoother" and hear the two for yourself?