Vintage Japanese DD Consult and Suggestions Please

@laaudionut, I don't have the broad experience like some (lewm) but hopefully can offer some helpful information.

First, if at all possible I would encourage you to find a way to keep your 301 long enough for a direct comparison with whatever replacement you find.  I've never had a 301/401/etc. but they are the top choice for many.  Others prefer a quality DD, so you need to determine which you like.

Second, there is great potential with some of the Japanese DDs such as you've mentioned.  But because of age any of those need to be "refreshed" (parts and calibration) by a knowledgeable technician if that was not done recently.  And sometimes parts can be difficult as with the Denon and SP-10 Mk 2(A).  Some of those motor units may not come with a proper plinth or a tone arm.  So depending on what you find used the costs can quickly add up.

Third, given the potential cost for an upgraded vintage Japanese DD, are there any new options that might be simpler and cost less?  Technics has introduced several upgraded models over the past few years, and there is a new Denon, though I don't know anything about it.

Good luck.

@laaudionut, "resembling DJ decks, which is not my preferred look, however. "

Yes, that is unfortunate and has caused lots of confusion for those looking at Technics products.  In fact the original SL-1200 was introduced in 1975 as a home audio product.  Through the years upgraded versions were introduced until the time where CDs severely impacted sales.  I've read Technics considered discontinuing that model, except sales suddenly increased because it was discovered by DJs which created a new market.  As a result the SL-1200 family became known informally as DJ tables due to their dominance in that field.  Now many consider it something designed for DJs rather than different purposed home audio applications.

So I considered it very unfortunate when Technics introduced the newly revised SL-1000/SP-10/SL-1200GAE a few years ago that they didn't redesign the overall appearance to differentiate it more from the older AL-1200 series.  That also seemed to drag along the DJ connotations, even while a much different design.

I overcame my own "look" prejudices more than a year ago and bought a SL-1200G.  I'm very pleased with the build and performance.

lewm, JP may substantiate this but I believe his chip replacement is for the SP-10 Mk 3 and the SP-15.  It is not a replacement for any of the SP-10 Mk 2 series.