A Turntable History Question


In late 1981, or January of 1982, I took a couple of my ward sisters out to the theatre (it was a Brian Rix farce at the Apollo). Returning to Harrow, I dropped off one of them and was invited in, where I saw her husband's turntable. It was suspended at each corner by many rubber bands, and years later I assumed it was an SME that I had seen. Now I know that SME were not making turntables at that time, I wonder what it was?

dogberry

@wbs

I stand corrected!  The SME website for the Model 30 series two states 60 rubber rings, plus one to counteract the pull of the drive belt, plus two spares!  Of note is the fact that these rings are clearly visible.  Rubber is an elastomer with some self-damping, but additional damping was built into the suspension towers.  The designer aimed for critical damping, so if the deck was pushed down and then released, it would return to the equilibrium position with no overshoot.

@richardbrand 

My Model 30 (s/n 0001) has 12 bands per tower plus the one band counteracting the belt pull.  It came with one or two extra bands, but I can't remember exactly.

@wbs 

I could never afford one, and I did stand corrected! I have found references to 10, 12 and 15 bands per tower depending on the series!

To me, using rubber to suspend a turntable makes perfect sense.  I had thought of suspending mine from the ceiling using bungee cords ... but it was a fleeting thought.  Suspending dynamic loudspeakers on the other hand makes no sense to me because there is nothing to resist the reaction of the cabinet to the movement of the cone.  When the cone moves forwards the cabinet moves backwards which muffles the overall sound.

Using a rubber band to connect a drive motor to a platter seems equally implausible to me - are such bands made so they don't stretch much?  I note SME's recommendation that the Model 30 drive belt should be replaced every 1000 hours (series 2) and also that the bearing should be run in continuously for a month, which is more than half the life of the belt!