If your records have warps in them and/or your turntable sits fairly close to your speakers, which probably is most of us, then a kab fluid damper will improve the s.q. allot.
However it is not an across the board improvement like a rewire would be and for those fortunate enough to have perfectly flat records and/or their TT far away from their speakers it would be a subtle improvement.
This is not to say a rewire is the answer. Unless you d.i.y. it will probably be $200-$300 with labor if not more which brings up the argument of just putting a whole new arm in or building your own sp25 table, buying or making your own plinth and tonearm.
Strongly disagree here... Fluid Damping has far greater benefits than most people realise...
The low frequency resonance is present on all arms (physics is physics) - but a damped arm (whether achieved electronically, magnetically or by fluid or other means), will control that resonance resulting in:
1) A reduction in Wow & Flutter - making things like piano sound a lot more real, and in general improving the sound across the range.
This is because the reduction in LF resonance, means that we have reduced "needle scrubbing" : as the arm rises and falls or sways left and right - vertical or horizontal resonance - the needles speed in the groove is being marginally increased or decreased, this is indistinguishable from platter speed stability issues, as it in fact amounts to speed stability issues!
2) Reduction in intermodulation distortions generated by the interaction of the low frequency fundamental and its resonances with the frequencies of the actual signal (music) being reproduced - this is a subtle but noticeably improvement in detail, the music itself coming from a clearer place as the "noise" around it is reduced.
3) Improved tracking - this is self evident when you think about it - the arm and therefore the needle is no longer moving about as much at low frequency - so it is more stable, and it is easier for the needle to maintain proper contact with the groove wall.
Along with improved tracking comes reduced sibilance, reduced inner groove distortion, etc...
Excess damping will however increase many of the same things that light damping reduces - as the arm is impeded from properly following the groove - resulting in increased needle scrubbing and reduced tracking performance.
Getting damping spot on can be tricky, as there are contributions to arm damping made by the bearings and their lubrication, the needles own suspension has damping built in, and then there is external damping such as fluid dampers.
Should Luckydog choose to join the conversation he may well provide more details on how to measure and calculate optimal damping...
My own experience with adjustable damping on a JVC QL-Y5F turntable shows that it is best approached lightly, but that once you properly (ie to the correct amount) damp a cartridge/arm combo, it definitely sounds better - with no other change to the setup.
In my opinion the single greatest improvement available to the SL1200mk2 (and its brethren) is via the installation of a fluid damper...
Re-Wiring, improved power, improved bearings will all provide improvements as well, but each of these is very subtle compared to the gains to be had from FD.... and the damper is one of the cheapest mods available!
All the aspects I mention are relatively easily measured and demonstrated - there are even a number of threads talking about DIY fluid dampers for all those TT's where an FD is not available... (paper clip, olive oil, jar lid, some tape and a bit of plastic cut up - the results are quite remarkable!)
Yes the electronically damped TT's provide the same magic, but in a more finicky and potentially troublesome way as they age.... and the TOTL JVC, Denon, Sony and Yamaha's all had electronic damping. (yes Yamaha... PX1)
Most of their competitors also had damping, though it was achieved with oil or magnets instead.
bye for now
David