Links (analog style) and downloads
Hmmm. Tired of calculating spring rates, natural frequencies...? Tired of periodic suspension tuning...?
Considering that the standard Thorens springs won't carry the load of the new frame, another spring rate is desired. I will try some different stronger springs. In the mean time I thought I would try an 'isolator grommet' rather than a spring just to see how it sounds. These grommets do isolate between the subchassis and the motor plate. I suppose it could still be called a suspended design because the subchassis is carried by the grommets.
The above idea uses a pair of the large Thorens rubber spring grommets and a length of automotive heater hose fitted in between at the three spring locations. I calculate the natural frequency of this spring to be less than 1 hz....;-) Stethoscope listening suggests that motor vibes aren't getting into the subchassis plate at all with this isolator grommet assembly.
I've played some vinyl in this configuration and have noticed a background noise level comparable to that of a 'spring equipped' TD150. Preliminary listening suggests some noticeable improvements in terms of musicality, detail definition. It's early. I'll listen some more. So far, only good descriptions come to mind.
Who says the isolation has to be by way of springs anyway....?