Best Tonearm for Thorens TD-124.

A well reconditioned 124 is a great table deserving of whatever top end arm one takes a fancy to. I don't think it favors, or is synergistic with any particular arm.  My local dealer, who recommends this table for some really high end systems, likes the top end Ortofon arms.  This makes for a quite reasonably priced combination.  If this does not seem like a high end combination, consider that he sells more Koetsu Rosewood Platinum cartridges than any other cartridge.

Reed makes terrific arms, so it is not surprising that it worked well with the TD 124.  Great table + great arm = sonic bliss.  I sort of dislike the notion that a vintage table should be matched to vintage arms; a table as good as the TD 124 deserves a good arm, including really good modern arms.  

Replacement, new rubber mushrooms would probably be the way to go.  My local dealer reconditions and sells a lot of these tables and new mushrooms are one of the basic steps in reconditioning tables.  The person who use to be the dealer's turntable repair/reconditioning/setup person (until recently), most often installs Ortofon and Koetsu cartridges.  He does not like the Black models of Ortofon as much as some lower-priced models because, to his young ears, they sound a bit bright and thinner than the other models.  I haven't heard the comparison myself.

All of the Ortofon arms became unavailable when Jelco shut down, which strongly indicates Jelco manufactured them.  In any case, they were terrific arms at a reasonable price.  This was one of the preferred brand of arms my dealer liked for both reconditioned TD 124 and Garrard 301 or 401 tables.  Audio Note arms and some Linn arms seem to work well too.