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."
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."