Which tonearm for vintage Micro Seiki BL-91

The MA-505 should provide a very good level of performance. I was very please with mine (on a modified TNT) before I switched to a VPI JMW-12 (on an Aries 1 extended).

The 505 is a very good arm. IMO, a bit dark, but very warm, damp and lush. In comparison to a Jelco SA-750D that I had also mounted on the same table, the 505 pretty much beat it in every category I can recall. And the 750D is no slouch arm. Carts were an AT OC9 and a Lyra Clavis da Capo. The CdC sounded pretty well-balanced in the 505 where it is bright (sometimes laser in the eyeball bright) in other arms.

BTW, the 505 I used (and still have) is a Mk II. Some might feel that it is a bit "gadgety" but it is very functional. Also has on-the-fly VTA over a pretty wide range. Very handy.

Comparing the 505 to the JMW-12 isn't quite fair in this case. The JMW-12 was mounted on a table (Aries 1 extended) that was quite a bit better than the TNT table. And further, the JMW-12 would never be a good fit, physically, on a BL-91. It's just plain too big, too long from arm pivot to platter spindle.

Email me off-line if you care to discuss the details of the 505 or get serious about looking around for one.

A MA-505 is a very good arm. Very musical. My only comment is that it's a bit dark. But that also makes it lush and involving.

There is a complete owner's manual collection on vinylengine dot com in their tonearm section. There is a detailed breakdown of the arm and all of its components. Also, an explanation of the workings of the arm.

If the anti-skate spring is loose and not repairable, that could be a problem. I can't remember all the specifics. You might check to see if the thread can be tightened. It might just appear that way because the thread is loose.