Should I use an external Phono Preamp

Pindac, So I guess the way to go is to riddle the poor guy with bits of conflicting advice, leaving him at least as confused as he was when he started. In one aspect, I do agree with you; each of us has to figure out for himself or herself what is the way to audio satisfaction, and that can only come about by personal trial and error or trial and success.

Suggesting a demo of a product available for a home loan is not causing any confusion, even if a minor fee is incurred to enable the demo to be realized.

The second suggestion is to use Amazon, taking advantage of their return policy. Amazon are 100% behind this; on a recent return to them made by me, they arranged the pickup by my local Postal service the following day to their being notified.  Using the Postal Service shows real commitment to being efficient in dealing with returns. 

I'm sure that the TTVJ Audio and Amazon route will enable an experience of a selection of SUT's. The OP and whoever else wishes to investigate the end sound being produced in their own systems will benefit from having the sat in front of experience. Talk doesn't cut it!!

Apart from parting with some money, the final bill should be a restock fee, and only if TTVJ Audio is requesting such a charge.

I see zero confusion; I see a clear route for the OP, where selections are best made, if experiencing the auxiliaries brought in for trialling prove satisfactory and are an attraction wanting to be maintained. 

The OP may end up with a standalone phon' and a new Tonearm, as many, many audio enthusiasts have also done. Where both additions are to be used in conjunction with already good integrated Phon's and a second Tonearm to adorn a Turntable.

If used items become the selected route to make purchases, I support them even further, as a contribution to supporting the Circular Economy is a biggy for me.   

I have decided to order the Ortofon ST-70 SUT which is designed to work with the Cadenza cartridges. I am hoping to achieve silence between tracks and equal or better performance. I will let everyone know how it turns out.

@mooks005 That’s a logical move with the SUT. And it paves the way for a cartridge upgrade as well. You’ll most likely have lower surface noise with a solid state SUT responsible for the MC gain. You’re going to need a set of phono cables or use your Valhalla 2 between SUT and McIntosh, and pick up a nice set of RCAs with ground wire or another set of phono cables between table and SUT. In that position any high quality interconnect will do as long as you use a ground wire - table to SUT with moving coil doesn’t require phono cables - capacitance isn’t a concern with MC cartridges. 

@mooks005 The ST-70 is an excellent SUT and will serve you well no matter what you do in the future.  I recommend that the extra phono cable you use with it be a match for the one you already are using and that you keep it as short as possible.  Also, in spite of lewm's assessment that my advice is "poppycock", he is entitled to his opinion after all, I stand by my advice that once you settle in with your new SUT, you go ahead and try that E-07, which I believe is well worth your consideration.  In case it is not obvious, the E-07 would also work just fine with with a transformer.  I have two external phono stages and use them both with and without transformers.  It all gets down to taste and what works best with cartridge selection.  Keep in mind too, that you and I share essentially very similar turntables, mine is the GAE version.  I also have other turntables.  Finally, like you I have an excellent built in phono preamp, mine in a Marantz, your Mac is excellent no doubt, but only by comparing them side by side can you determine if the E-07 is better, and if so enough better to be worth the cost to you.  There has been a lot of conflicting opinion expressed in this discussion.  Do not let that distract you.