Ampdog
R.I.P. 23 June 2022
I am starting a new topic on anything generally relevant to record player set-up: Hints, difficulties, experience - because I think there might be some interest. We occasionally went astray on Hein's thread about a dream turntable; let's do it here and post on Hein's thread only what is relevant to his subject - but not neglect that thread now!
Ludo asked in his last post there:
My thoughts would be along the lines of placing a high frequency strobe disc on the record being played and strobing it with a high frequncy strobe light. Then, alternately placing/lifting the pick-up on a loud piece of music on the particular record. But I am not sure as to how sensitive such a system would be. Calculating the difference in strobe frequency as % of rotational speed will reveal the effect.
But there is of course the matter of where it will be most. Greatest effect on the outside of the record in terms of slowing moment, but the greatest drag (because of groove angle) would be on the inside of the record. I would rather go to mathematics and calculate at what force the stylus tip would leave the groove, what is the stylus drag on the record then, and to what degree such drag will slow down the platter. I have at present little data; perhaps others can oblige. RDH (Langford-Smith) deals with this, but matters were quite different in those days from our light-weight super-tracking cartridges of today. Some relevant data is available from high-end cartridge specs. Let us see.
Ludo asked in his last post there:
ludo said:
My thoughts would be along the lines of placing a high frequency strobe disc on the record being played and strobing it with a high frequncy strobe light. Then, alternately placing/lifting the pick-up on a loud piece of music on the particular record. But I am not sure as to how sensitive such a system would be. Calculating the difference in strobe frequency as % of rotational speed will reveal the effect.
But there is of course the matter of where it will be most. Greatest effect on the outside of the record in terms of slowing moment, but the greatest drag (because of groove angle) would be on the inside of the record. I would rather go to mathematics and calculate at what force the stylus tip would leave the groove, what is the stylus drag on the record then, and to what degree such drag will slow down the platter. I have at present little data; perhaps others can oblige. RDH (Langford-Smith) deals with this, but matters were quite different in those days from our light-weight super-tracking cartridges of today. Some relevant data is available from high-end cartridge specs. Let us see.
