Analog upgrade path

I would first upgrade the cartridge to an advanced stylus shape.

https://www.sound-smith.com/articles/stylus-shape-information

If you play it (MM or MC) thru your VA 1400 first, you will hear only the improved cartridge. 

Then, to use your two nice pieces, you need to get a phono stage as you know. I would go for one with inputs for two tonearms, MM input and MC input with options to accommodate your new cartridge and future new MC cartridges with different signal strengths and coil impedances.

You will definitely have a much nicer sounding system,

Well, this seems to be escalating quickly...
That Soundsmith Voice cartridge is well outside my budget. The article on stylus shape was certainly informative, however.
$4-5k was my (now very much blown) original budget for getting a complete system up and running lol.

Oh, my power amp’s s/n is 92.5db, since that was mentioned.

Any thoughts on the Goldring 2500? I’d been looking at that cart previously.

goldring.. 1042 is excellent mm cart. and it's cheap. 

It can do alot of things and alot to like for the price. hard to do any better below 1000 usd

I saw it trounce a high price Mc before

it's one of those cart that makes music sound like it supposed as intended. not too much not too little. I highly recommend it

basically kick nagaoka mp 500 out of the park too and some others. many upset people lol

It can do alot of things and alot to like for the price. hard to do any better below 1000 usd

Why do you trust people who never owned good MM cartridges ?

You’d better ask for a list of cartridges from the owners of Goldring before they will tell you this is the best.

Some people don’t even know about better cartridges, they never heard about Garrott Brothers, because they are British or Americans, but it’s Australian cartridge. I have never ever read from anyone about direct comparison of Garrott Dynamic Coil cartridges to mainstream like Nagaoka, Goldring or whatever.

However, cartridges that kills many of those overpriced LOMC are not new MM/MI, but vintage MM from the golden age of MM design (70s/80s). Those are unique in many aspects of design.

BTW Nagaoka is very old design, in Japan this company called Jeweltone and all those PM-100,200,300,500 designed in the 70's and sold in Japan under Jeweltone brand models MP-10,20,30,50 (Nagaoka is only export name for same cartridges).