I just landed a Luxman PD444. Does anyone here have personal experience with this table? Also, a pointer to the service manual would be much appreciated. There is nothing on Vinyl Engine or anywhere else via web search.
Assuming that it arrives in good working order as advertised, I suppose the first step will be to re-cap the electrolytics and attempt to inspect the condition of the bearing. This may be a challenge, as a poster has written that the bearing is sealed.
It's an interesting design. Luxman literature indicates that its slotless DC servo motor somehow levitates 4/5 of the 2.5kg platter weight without resorting to a permanent magnet around the bearing. Here is an extract from the owner's manual:
"The PD444 employs a slotless, flat DC servo motor that offers a small amount of torque ripple from theoretical viewpoint as well. It is so designed as to obtain an even torque regardless of the rotor position, thanks to the brushless structure with hall elements which detects the rotor position.
In addition to conventional speed control by means of a frequency generator circuit, a so-called "Quartz Lock" system is employed utilizing a PLL system...crystal oscillator. Therefore, the open-loop gain in DC area becomes infinite, which helps suppress external load variations in low frequencies. Also, the rotation speed is locked to the... crystal.
The QL system is effective in the suppression of external load variation from DC area to 1Hz. To reduce those load variations of relatively higher frequencies(5-10Hz), the flywheel of the (heavy) platter is effective.
But coupled to these advantages are such problems as shorter life of the bearing, and longer rise and decay time. Our exclusive "Load-Free Spindle"...solves these problems. The phono motor itself offers the repelling power to the spindle to float the platter, unlike conventional magnet-float systems.
The driving current to the motor is small, and such characteristics as S/N ration and wow and flutter are improved." |
Lew, I use a Resomat and prefer it to direct coupling on my L07D and VPI TNT. However, the Resomat can sound a bit light and tizzy without a clamp or record weight to bring the LP into full engagement with the two full circles of vinyl cones on the mat that mate with the record lead-in and run-out sections. Too much weight or pressure becomes counter-productive, cupping the LP away from the outer circle of cones. To prevent cupping I stack rubber washers on the spindle above and below the Resomat. When the record weight is applied the perimeter cups down.
All of this may seem like too much trouble, but it's really no big deal. |
Lew, The Resomat is almost weightless. It consists of a paper-thin acetate sheet that serves only to fix the locations of the small and lightweight vinyl acetate cones that couple the record through the sheet to the OEM platter. The cones pass through the sheet and their bases rest directly on the TT platter. So the idea with this mat is not to isolate the LP from the platter, but rather to couple it at two radiuses. The mat is available in several versions: short cones or long cones designed to clear the raised lip of an SP-10 platter.
With L07D I'm using a sandwich arrangement. Stillpoints LPI record weight over short-point version of Resomat over TTW Weights 4 lb./4mm solid copper platter over ERS cloth mat over Kenwood steel plate. The Kenwood's tall spindle is just long enough for all of this.
The weight of the copper mat is pretty close to the weight of an original Kenwood perimeter ring. The performance with the copper mat is improved by pressing the button on the L07D PS that was conceived for the perimeter ring.
Jcarr, very helpful & thank you for the info. |
Fleib, in the course of marketing capacitors designed to reduce self-propagated microphonics, one of my most interesting interviews was with a respected OEM of TOTL tube amps who had been winding bespoke coupling capacitors with lead foil. He maintained that owing to its superior damping property, lead sounded better than much better conductors like copper or silver. |
Lew, At RMAF I heard two Dohmann TT set-ups, both among the better analog presentations at the show. Dohmann incorporates a Minus K spring-based vibration platform into the plinth. A friend of mine has had great results with the Minus K with another TT. Perhaps it's worth pursuing. |
That’s interesting about the life span of electrolytics. Electrolytic manufacturers typical spec capacitor life at several thousand hours--though I suppose that this is calculated at the most extreme conditions of voltage and temperature. I only have anecdotal experience with their failure in TTs. My L07D lasted about 300 hours before exhibiting speed instability due to a failing electrolytic. I then replaced them all. |
Hello Harold, Congratulations on your PD444. I haven't yet tried the Terminator arm on my PD444, as it would be too crowded for three tonearms-- which was one of my reasons for the Luxman purchase. I tried Resomat on top of the stock Luxman rubber mat, but found that combination weak in the presence region. So what do you make of the Luxman as compared to the Salvation? Have you tried the redesigned Terminator slider with banded bearing cups? I have one that I need to test soon. |
Harold, you already had the disease. It just mutated.... On Terminator the inside corners of the aluminum angle "thrust pads" on which the two needle bearings pivot, are replaced by thick, tensioned horizontal rubber bands. The pivoting needles fix their locations during break-in by slightly penetrating into the rubber. I assume that this new approach adds damping, and-- after the needles have seated into the rubber-- imposes a small dynamic counterforce against the wand’s vertical travel. I can imagine that the dynamic weighting could be helpful to a short wand of light vertical inertial mass..
Audio_d, I hope your friend had all the electrolytic caps replaced in his SP-10. Aging electrolytics are probably the biggest risks in living with a vintage DD. I routinely replaced them all in PD444, LO7D, and SP-10. |
It's a bit more complicated than that. Each slider is matched to its air manifold at factory. To update a slider to banded cups you need to break off the alum bearing cradles glued to your existing slider, then glue on replacement cradles that accommodate the bands. I'll post a photo after finishing this (delicate!) operation. |
Chakster, The only differences between those PD444 armboards is the top plate that covers the locking frame that clamps the armboard to the turntable rails. It's a simple job for a machinist to make interchangeable top plates from 3/8" to 1/4" thick and with holes of varying size to accommodate pretty much any tonearm. For a particularly tall tonearm(like the Kuzma 4P), I needed to remove the top plate entirely and mount the tonearm directly down into the locking frame. The PD444 is definitely a top performer. You might try replacing the stock elastomer feet with Stillpoints or Audio Points. |
|
I've used brass for ease of machinability and stainless steel should be good as well. |
@chakster I'm not so sure about that. I removed the stock switch box from under my PD444 and substituted a thick, dense wenge wood subplinth that projects forward as a subplinth for a third tonearm mounted to a Micro Seiki brass tonearm board. The big surprise is that SQ was improved for the other two arms mounted to the stock tracks. The subplinth must be acting as a sink for vibration. |
There are a couple of photos of the modded PD444 on my system page: https://systems.audiogon.com/systems/702#&gid=1&pid=2 I replaced the stock feet with machined brass towers and Stillpoints Ultra 5s-- with a fifth U5 under the motor housing. My 444 came to me with one foot missing-- in all honesty I never heard it with the stock elastomer footers. I do love this table, and put it at the same level as my L07D. I also substituted a 4mm TT Weights copper platter mat for the stock rubber mat on the 444. That was an improvement.
|
