LammLP2 vs. Arc PH_7

I own a Lamm LP2 Deluxe, but haven't heard the ARC (though I far preferred the Lamm to prior ARC units I had heard, just seemed more like music, the ARCs being more to the analytical side). To my aging ears the Lamm is slightly dark-sounding, excels at layering of images in a soundstage, is tonally correct, has excellent dynamics and, as Damaradona points out, is very quiet. However, part of that quiet is because it only has 57db of gain. Kurt tank is correct, it can be magical with some cartridges, but its limited gain means that it may disappoint with very low-output MCs (I ultimately gave up with my Koetsu RSP, just not enough volume to convey power music or records cut at a low level). And the inability to play with the impedance is also a drawback. I solved those problems to my satisfaction by getting an EMT cartridge with its matched step-up transformer, though there are certainly many cartridges that will work fine with the Lamm by themselves.

Hopefully some PH-7 owners will give their observations for you.

I considered the Shelter, which is a very nice cartridge and should have more than enough output to work well with the Lamm. However, I preferred the EMT JSD5, as it had much of the midrange of my Koetsu RSP, better bass and dynamics, and a good deal of gain (I only use the step up because it was ideally matched for the cartridge and a better loading match than the transformer in the Lamm's MC stage, not for the additional gain). Works well with my Graham 2.2, also, so it should work nicely with your Phantom. The Shelter sounded a little less vivid and lush to me (I almost want to say a little homogenized in comparison, but that would not be fair to the Shelter, which really is one of the better ones out there), and I wanted those qualities because I listen primarily to classical music and admit that I like the Koetsu "sound". A lot of the modern cartridges are sounding more and more like CD to me, which is what a lot of people like; I prefer a little more of the old-fashioned vinyl warmth.

By the way, very nice system!