Help.... I'm scared to 'upgrade'!

Those 2 nice cartridges you have (Cadenza Black, Umami Red) are electrically in the "sweet" range for a SUT (15x - 20x), so you might consider one of those partnered with an MM stage. Hum / grounding can be a pain with these, but if you do it right the SUT gives "free", relatively noiseless gain, which seems to be very important to you. The other way to combat noise floor is to move to a higher output cartridge, but I'd hate to suggest that given you've already got very nice low (but not too low) output ones. 

The other suggestion for current injection / transimpedance stages is good too. You tried a few traditional SS and tube stages and didn't like them, so your choices are: 1. Keep trying, 2. Go WAY up in quality & price point, 3. Try a different approach 

IMO, you haven’t tried a really great phono stage yet, so it’s premature to conclude that the iFi Zen is some sort of giant killer. Most testimonials from other users would suggest that it’s not. It seems to be a good to very good phono stage “for the money “ and not more than that. If you own and only plan to own low output MC cartridges with very low internal resistance (e.g., less than 10 ohms), you might really like the BMC mentioned above or some other current driven phono of high quality. There are several other choices of phono stage that should outperform anything you’ve heard in your system. The other question that arises is whether the linestage section of your Accuphase E470 is limiting your capacity to get the most out of any phono stage. Something to think about.

Good points to consider, all...

@mingles, I have indeed ordered an upgraded power supply, as well as a 4.4mm Pentaconn to XLR adapter so as to take advantage of its balanced output. It will be interesting to try to discern any changes with one, then both of those.

@chetatkins Curious, why might it be better to bypass the Bryston Isolation Transformer (BIT15) that the rest of my system is on?

@fuzztone I’m going to keep that nifty Puffin unit in mind should I ever want a digital archive of my library. Plus the azimuth readout is very cool. It’s an example of just how rich the analog world is right now.

@boothroyd A Sutherland transimpedance stage is on my short list. And @mijostyn I’ll take another look at the Channel D Lino C. I remember being impressed by a write up some time ago, maybe from Fremer’s site.

@lewm Yes, which is why the Accuphase C-47 is my aspirational piece. I haven’t found out its US list yet, I think it’s around $13,000. To get there will require some saving and selling but at the very least that little Zen Phono makes waiting fun, eh?

What do you want good sound that you are happy with or a line item in you bank account that you can look at brag about and try and convince your self that it cost this much it must sound good. This forum is famous for people who spend thousands for a piece of gear that they don’t like the sound of. Then they post and the replies come in must not have it set up right, wrong power supply, wrong interconnects, wrong amp, wrong pre amp, wrong speakers, wrong room treatments, but never you just over paid for a piece of garbage cause it was expensive it can’t be bad. I am there with my dac. Current on cost me $500 and weekly I tell myself I need to go buy one for $2000 as it has to be better than current. Then I listen to my system and really enjoy the sound and like even better seeing my bank account balance $2000 higher than it would be!

@sgreg1 , You get out on the wrong side of the bed today?