Ralph, What are you doing with a lathe? Atma-Sphere going to start making records?@mikelavigne We've been mastering LPs for about 5-6 years. Most of the projects we've done are local. It took some time to refurbish the machine and sort out how to operate it. Fortunately I had some help from Len Horowitz of HRS.
Stylus-Drag..Fact or Fiction?
Most audiophiles can't seem to believe that a tiny stylus tracking the record groove on a heavy platter could possibly 'slow-down' the rotating speed of a turntable.
I must admit that proving this 'visually' or scientifically has been somewhat difficult until Sutherland brought out the Timeline.
The Timeline sits over the spindle of the rotating disc and flashes a laser signal at precisely the correct timing for either 33.33rpm or 45rpm.
By projecting these 'flashes' onto a nearby wall (with a marker attached)....one can visualise in real-time, whether the platter is 'speed-perfect' (hitting the mark at every revolution), losing speed (moving to the left of the mark) or gaining speed (moving to the right of the mark).
RAVEN BELT-DRIVE TT vs TIMELINE
Watch here how the laser hits the mark each revolution until the stylus hits the groove and it instantly starts losing speed (moving to the left).
You can track its movement once it leaves the wall by seeing it on the Copperhead Tonearm.
Watch how it then speeds up when the tonearms are removed one by one....and then again, loses speed as the arms are dropped.
RAVEN BELT-DRIVE TT vs TIMELINE
Watch here how the laser is 'spot-on' each revolution with a single stylus in the groove and then loses speed as each additional stylus is added.
Then observe how....with NO styli in the groove.....the speed increases with each revolution (laser moves to the right) until it 'hits' the mark and then continues moving to the right until it has passed the mark.
Here is the 35 year-old Direct Drive Victor TT-81 turntable (with Bi-Directional Servo Control) undergoing the same examination:-
VICTOR TT-81 DD TT vs TIMELINE
I must admit that proving this 'visually' or scientifically has been somewhat difficult until Sutherland brought out the Timeline.
The Timeline sits over the spindle of the rotating disc and flashes a laser signal at precisely the correct timing for either 33.33rpm or 45rpm.
By projecting these 'flashes' onto a nearby wall (with a marker attached)....one can visualise in real-time, whether the platter is 'speed-perfect' (hitting the mark at every revolution), losing speed (moving to the left of the mark) or gaining speed (moving to the right of the mark).
RAVEN BELT-DRIVE TT vs TIMELINE
Watch here how the laser hits the mark each revolution until the stylus hits the groove and it instantly starts losing speed (moving to the left).
You can track its movement once it leaves the wall by seeing it on the Copperhead Tonearm.
Watch how it then speeds up when the tonearms are removed one by one....and then again, loses speed as the arms are dropped.
RAVEN BELT-DRIVE TT vs TIMELINE
Watch here how the laser is 'spot-on' each revolution with a single stylus in the groove and then loses speed as each additional stylus is added.
Then observe how....with NO styli in the groove.....the speed increases with each revolution (laser moves to the right) until it 'hits' the mark and then continues moving to the right until it has passed the mark.
Here is the 35 year-old Direct Drive Victor TT-81 turntable (with Bi-Directional Servo Control) undergoing the same examination:-
VICTOR TT-81 DD TT vs TIMELINE
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- 169 posts total
Ralph, I asked that question. It is not easy to master high quality records. We hear the results which are not always optimal. I was just listening to Kate Bush's "Before The Dawn." The rumble forced me to turn my subwoofers down. It is a common problem with remastered albums. I assume this is from poorly maintained lathes. It is a very rare problem with older pressings. Even rarer in old classical pressings. Anyway, who do you send the masters to for pressing? Mike |
Just some random thoughts and maybe I missed this. In my industrial world, traditional motor absolute speed control was obtained by either servo motors/ controllers or motors with speed encoder feedback. However in past few years drive controllers have become so sophisticated that now best speed regulation is obtained by running " open loop" with zero encoder feedback and using current feedback at the controller itself. Now is this a possibility for TT speed control or is this how some are already controlled? |
Non-feedback motor control the above approach is with the CS Port LFT1 turntable http://www.csport.audio/products/products-lft1-en.html |
- 169 posts total