I had a chance to experiment this evening. I used some rubber shims to constrain the sub chassis on my turntable in the horizontal axis. My Sota has the motor fixed on the main chassis while the tonearm and platter float on the sub chassis. First, I put on my test record to check speed with the iPhone app. Speed was 5 Hz high. So belt tension must have changed. I tried to keep the sub chassis in a neutral, level position. I adjusted speed and checked WoW & Flutter with the app. I saw right away that the FFT waveform is a clean sawtooth pattern now. Before the sawtooth pattern had a lot of hitches in it. I think this is already an improvement. Speed is within 0.025%. That is an order of magnitude higher than Peter's turntable; but pretty good I think, for an open loop motor. The timeline laser mark would move around 10X faster on my table than on some others. WoW & Flutter measured 0.02%/0.03%; typical.
Listening: First, I tried "For Duke". This is a technically near perfect direct to disc record and good music too. Rhythm and Pace seemed about the same to me. The bass seems cleaner and sharper. Should I expect that to be the case?
Next, I put on Beethoven's Appassionata. This is another direct to disc cut at 45 rpm. Sounded fantastic as always. Very powerful. I was hearing some micro detail that I had not heard from this record in years. eg. I could hear the pianist take in a breath just before hitting the keys. Would you expect to hear more detail? Again, I think the lower registers of the piano had more power.
I think overall it is an improvement. It was clearly seen on the iPhone app. So next step for me is to come up with a way to constrain the horizontal axis and leave the vertical axis free.
Listening: First, I tried "For Duke". This is a technically near perfect direct to disc record and good music too. Rhythm and Pace seemed about the same to me. The bass seems cleaner and sharper. Should I expect that to be the case?
Next, I put on Beethoven's Appassionata. This is another direct to disc cut at 45 rpm. Sounded fantastic as always. Very powerful. I was hearing some micro detail that I had not heard from this record in years. eg. I could hear the pianist take in a breath just before hitting the keys. Would you expect to hear more detail? Again, I think the lower registers of the piano had more power.
I think overall it is an improvement. It was clearly seen on the iPhone app. So next step for me is to come up with a way to constrain the horizontal axis and leave the vertical axis free.