Zaikesman, did you ever get around to writing a review of the KAB PS-1200 external power supply? I'd love to hear your thoughts.
Joe
Joe
Review: KAB SL-1200 Fluid Damper Tweak
Update: I recently received a new paddle assembly from KAB, to replace the original that I busted by accident. During the interem while awaiting my new paddle's arrival, I was reminded, in the first absence of active damping from my tonearm since I started this thread, just how much this modification does for the sound. Anyway, it turns out that the old, outsourced plastic paddle (which attached to the tonearm by means of a hinged plastic collar with plastic thumbscrew, that fitted around the armtube) has been replaced by one of Kevin Barrett's own design, nicely made (like the fluid trough) of machined aluminum to match the turntable chassis deck. I don't know how long this upgrade has been in effect, but now that I have it I wanted to report on it. The new paddle attaches, by means of a machined-slot/metal set-screw combination (again similar to the trough and the way it attaches to the base of the stationary gimbal support), not to the hollow armtube itself, but to the small, solid cast-aluminum side-arm that protrudes inward from the bearing-housing piece that carries the armtube, whose regular function is to interface with the hydraulic arm-lift actuator. This is an ingenious solution (that doesn't interfere with the arm-lift), and because it's constructed of one solid aluminum piece, should last forever (unlike, as I found out, the former plastic version). And not only is its appearance more integrated with the turntable, it also looks to me like this paddle presents a larger surface area for the fluid in the trough to act upon. (See a photo here -- the KAB paddle is just below and to the right of the locked armrest, although you can't see its business end from this vantage point. The armlift actuator -- as opposed to the lever -- is the curved black rubber-topped piece nestled behind the curved aluminum KAB damper fluid trough.) Unlike the previous paddle however, which could be rotated about the tonearm to achieve different immersion angles and depths into the viscous silicone damping fluid, the user cannot adjust this new paddle -- it has one fixed, presumably correct, position. That's fine with me -- one less thing to play around with and get wrong. You can still adjust the level of the fluid in the trough as you wish to control the total amount of immersion and therefore damping. The only downside of this arrangement is that you also lose the ability to rotate the paddle out of the trough entirely in order to make balancing of cartridges go quicker. (Of course you can't simply remove the paddle from the tonearm since subtracting its weight would change the balance.) So if you don't like rebalancing your cartridge/headshell swaps with the paddle still in the fluid, the only way to go is to remove the trough itself, a bit more of a hassle which probably means (if you're not to risk making a sticky mess with the silicone) carefully removing and cleaning the paddle first, then removing the trough, then reinstalling the paddle and setting your balance, then going through the reverse to reinstall the trough. Personally, when I installed my replacement paddle for the first time, I just lived with it being immersed in the fluid -- since my trough was already installed and filled -- and simply allowed the required extra settling time when setting the tonearm balance, and this is what I'd suggest you do too for any rebalancings after the initial setup. (After all, the tonearm is ulitmately going to be played with the paddle in the fluid, so why not leave it there for set-up too?) I suppose the only other reservations that some fanatic (like me) might come up with about the new paddle is that its attachment point has moved about half an inch closer-in to the pivot-point from before (theoretically, the ideal damping point would be out at the headshell, far away from the pivot), and the fact that the damper no longer attaches directly to the armtube itself, but to a separate piece that is in turn attached to the armtube. But I think these items are probably of about zero importance all told. (Oh, and you will need more than your fingers to install this version of the paddle, you will need the correct Allen key, same one as for attaching the trough -- lock your tonearm first and use the short end, the clearance is a bit tight but it's no problem if you go slowly and use appropriate care.) If you own an older TD-1200 damper with the plastic paddle, it's an under-$30 upgrade to switch to the current version, and one I would recommend purely for aesthetic and durability reasons. (As you may have surmised, I can't do a direct sonic comparison between the new paddle and my old one, since that's both broken and thrown away, but puh-leeze...I wouldn't bother anyway.) As a possible bonus on the side, assuming the metal paddle is unavoidably somewhat heavier that the plastic one, if your cartridge is slightly too lightweight to use with Technics' screw-in auxillary counterweight attachment, you might be able to do it with this paddle attached. Adding the auxillary counterweight, and the resulting repositioning of the main counterweight closer to the pivot-point, could have a side-effect of favorably impacting residual tonearm resonance. On the other hand, if you have a Technics 1200 (or are thinking of buying one) but haven't gotten Kevin's damper kit yet, you should know that he hasn't raised the price since introducing the new paddle, even though I'd imagine his cost for engineering and subcontracting manufacture of this bespoke part has got to have taken a bite out of his bottom line. So nice job KAB of making a good product better while holding the line on the price. |
Hi Detlof, and thanks for checking in on me :-) I may not have been "cured" as you say, but I've been doing my best to keep it down to a low roar, and ceasing to write about the subject every day has helped. (That and, sad to say, getting burned a bit on a handful of Agon deals in succession.) In any case, although my system has continued to evolve substantially since I last documented any changes in the forums, overall I'm glad to get back to focusing more on my music and less on my rig -- or, frankly, anyone else's. (Though I admit to recently having taken some small satisfaction in belatedly learning of the esteemed Albert's direct-drive/Technics conversion, albeit on a much higher plane!) Anyway, now that I reread my update again a few days later, one thought I'd like to add about the new paddle: As I mentioned but downplayed, it attaches a little closer to the pivot-point and not directly to the armtube like before. However, it occurs to me that since it is now made of solid aluminum and attaches more rigidly to a piece of the same -- implying improved mechanical impedance-matching -- there should be a not-insignificant payoff of improved high-frequency conductivity in the mechanical pathway to the damping fluid. Despite the supposed benefits listed on the KAB website (see the link in my previous post) having mostly to do with record warps and external vibrational inputs that are primarily low-frequency in nature, in my personal opinion the lessening of these effects is not the main reason for the active damper's sonic effectiveness. Based on the evidence I've heard, as indicated by the benefits listed in my review at the top, I've concluded that a dynamic fluid damper offers musical improvments regardless of whether and to what degree factors like record warps, woofer-pumping or ambient speaker volume-level come into play. I think this is because the main vector of its action has mostly to do with the audio-band energy (including mid- and high-frequency energy) generated by the stylus itself as it transcribes the music vibration in the groove, and how that energy is handled in its transmission to the tonearm. After all, a property of the viscous silicone fluid, like any compliant damper, is that it functions as a low-pass filter, so it allows slower movement (like not impeding the tonearm from tracing the groove across the record's radius, and permitting it to follow a record warp or deal with an off-center spindle hole), while progressively damping higher-frequency movement (like overshoot and ringing resulting from attempting to track a record warp). So the higher the frequency of the impulse input into the tonearm (e.g., audio-band excitation resulting from playing music), the more effectively it is absorbed by the fluid. But this energy (and the resonances it induces) must be transmitted to the trough before it can be damped, which is why the HF vibrational conductivity of the paddle matters, and common sense says a rigid metal paddle of matching mechanical impedance ought to be superior in this regard. I don't want to overstate the possible benefit, which as I said I am not in a position to ascertain by direct comparison, but I suspect it should more than make up for any slight relative disadvantage in theory of the new attachment point. |