Restoring and upgrading a Thorens TD150 (mk 1)
The Client suggested that I was to make this TD150 as if it were for myself. That left a lot of possibilities open. I also learned that the Client would be making comparisons between this TD150 and a VPI Scout belt drive turntable and to a Technics SL1200 series direct drive turntable. He has also owned a couple of Rega turntables, and an LP12. So the question becomes just how well can one of these old vintage pieces fare in the above comparison? Let us presume that an answer to that question will be forthcoming.
After consideration of all the possibilities that I could imagine, and then appraising said costs, my view on potential upgrades was distilled down to, first and foremost, that the turntable must make use of its own parts. That is; its own platter and bearing. Its own sub-chassis, motor plate and motor. However, the spring suspension will be altered to correct extreme footfall issues of the suspended wood flooring where the turntable is to be used.
Dampening materials are not to be applied to either motor plate or sub-chassis. Rather, let us make sure that the motor runs as smoothly, quietly and true as it should and that the platter bearing has correct working clearances and lube. The stock build of the TD150 I find to be somewhat more robust and substantial than for its successor, the TD160.
A new constrained layer plinth of stacked-layer Baltic Birch is designed and constructed to house the turntable. BDR cone footers are used. A new (nos) Jelco SA370H tonearm is supplied and a solid Cherry armboard to support it is a requirement. A mounting bracket for RCA jacks and ground is also specified. In this case a KAB PC-1200 bracket assembly is supplied and to be mounted from beneath the plinth. Several different headshells that fit the Ortofon style quick disconnect mount at the front of the Jelco will be setup to hold a variety of different phono cartridges, including a Dynavector DV20X (low), an Ortofon 2m Black and a Denon DL-103 with custom Ebony body from Uwe.
Jelco SA-370H (schematic with geometry specifications)
The assembly shows the wiring hook-up. Ready to go into the finished plinth. A new motor cap replaces the old one. Same value but of a higher grade. (5%) Note; these motors will work on either 50 or 60 hz but require 110-120 volts AC. In countries where the AC mains is 220-240 VAC, a resistor is used to reduce the voltage to 110-120vac. This turntable was assembled by Thorens for use in North America. It is good to know this before plugging in.
And now with plinth finished:
Above image: An assembly view detail of the Thorens TD150 suspended sub-chassis. It is a 4 piece spot-weld fabrication made from .060 (inch) thick steel sheet.
note: all imagery on this page is © The Analog Dept.