Schroder lT installed, pics a few comments...
- Thread starter jfrech
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Frank, I have a question. It seems as though the arm pivot point moves along an arc so that the stylus can maintain perfect tangency, regardless of where it is on the LP. As the arm moves along this arc, the stylus is moving very slightly more or less in the plane of the groove as it spins by in the direction of the LP, as well as toward the spindle like in a conventional pivoted arm. With a pivoted arm the stylus moves along a flat arc toward the spindle only. Otherwise it is fixed against the flow of the groove. Does this tiny movement along the axis of the groove mean that the stylus is moving very slightly less than 33.3333 RPM? In other words, does your arm design effect the speed of the stylus traveling through the groove, even very slightly?
Hi Peter,
Yes, the arm's geometry will affect the actual rpm, --- just like a conventional pivoted arm does(think about it...
. Only a straight line, linear tracking arm doesn't produce this effect.
BUT.... according to this:
http://en.wikipedia.org/wiki/LP_album
"The average LP has about 1,600 feet of groove on each side, or about a third of a mile."
So the discrepancy(less than two inches or 5cm) will not be perceivable by mere mortals. Even very high quality measuring equipment won't show that difference.
Happy New Year!
Frank
Yes, the arm's geometry will affect the actual rpm, --- just like a conventional pivoted arm does(think about it...
. Only a straight line, linear tracking arm doesn't produce this effect.BUT.... according to this:
http://en.wikipedia.org/wiki/LP_album
"The average LP has about 1,600 feet of groove on each side, or about a third of a mile."
So the discrepancy(less than two inches or 5cm) will not be perceivable by mere mortals. Even very high quality measuring equipment won't show that difference.
Happy New Year!
Frank
Hi Peter,
Yes, the arm's geometry will affect the actual rpm, --- just like a conventional pivoted arm does(think about it...
BUT.... according to this:
http://en.wikipedia.org/wiki/LP_album
"The average LP has about 1,600 feet of groove on each side, or about a third of a mile."
So the discrepancy(less than two inches or 5cm) will not be perceivable by mere mortals. Even very high quality measuring equipment won't show that difference.
Happy New Year!
Frank
Hello Frank, That is what I thought was going on and I figured the distance was negligible. Thank you for the confirmation.
Another question: How does your LT arm deal with overhang changes when adjusting VTA? I've recently been surprised when I discovered just how much the overhang is effected, especially for the outer grooves, with my 12" SME V-12 arm when I adjust the VTA by as little as 1-2mm, or less than half a degree of SRA. With a conventional linear tracking arm, if the VTA is adjusted and the supporting rail is not adjusted for overhang, then I would think the stylus is running toward the spindle in a line parallel to the radius of the record, but not truly on the radius. That should effect tracking error. Could you please shed some light on this topic?
Hi Peter,
Didn't see your follow up question, sorry....
On (almost)ANY arm, be it a linear tracking arm or a pivoted arm, the effective length and therefore the overhang will change once the arm's bearing for the vertical movement is moved up-or downward. As far as I recall, only the ET2 linear tracking arm features a base that takes the displacement into account. On my magnet/thread bearing arms, any VTA change is essentially compensated for by the armwands's forward movement when the back is raised and vice versa.
On a pivoted arm, the resulting changes will simply "move" the Null points and increase the distorsion maximum ever so slightly.
On a linear tracking arm, the displacement is easy to calculate(Pythagoras) and may only become a problem with very short linear tracking arms.
Don't forget that the eff. length changes too when you alter the tracking force.
Again, the actual change is usually below the threshold of repeatable adjustment accuracy achievable by a normal human being.
All the best,
Frank
Didn't see your follow up question, sorry....
On (almost)ANY arm, be it a linear tracking arm or a pivoted arm, the effective length and therefore the overhang will change once the arm's bearing for the vertical movement is moved up-or downward. As far as I recall, only the ET2 linear tracking arm features a base that takes the displacement into account. On my magnet/thread bearing arms, any VTA change is essentially compensated for by the armwands's forward movement when the back is raised and vice versa.
On a pivoted arm, the resulting changes will simply "move" the Null points and increase the distorsion maximum ever so slightly.
On a linear tracking arm, the displacement is easy to calculate(Pythagoras) and may only become a problem with very short linear tracking arms.
Don't forget that the eff. length changes too when you alter the tracking force.
Again, the actual change is usually below the threshold of repeatable adjustment accuracy achievable by a normal human being.
All the best,
Frank
Thank you again, Frank. Your explanation makes sense. I agree that these changes are very slight and in most cases, to most ears, and in most system, they are not audible. In my case, I'm not sure I know exactly what to listen for, anyway. However, I have found that with my 12" arm, even slight changes in arm height of 1-2mm is audible, so after years of not changing SRA for different LPs, I now do this regularly at the expense of other alignment parameters such as effective length, overhang, VTF, etc. I was just curious about this issue with linear tracking arms, and you gave a very clear description. Thank you. I look forward to hearing your LT arm someday. It is already in a couple of good systems here on WBF. From what I can tell from reading, it is a serious arm that attempts to address the tracking issue. Congratulations.
Hi Peter,
On most tonearms, changing arm "height" or VTA by more than 1mm will have an effect on the tracking force, likely to be audible. Some carts have a VTF "sweet spot" that is within +/- 0,02gr. A VTF change any larger will alter the vertical cantilever deflection enough to dwarf the 1-2mm VTA/SRA change.
Best,
Frank
On most tonearms, changing arm "height" or VTA by more than 1mm will have an effect on the tracking force, likely to be audible. Some carts have a VTF "sweet spot" that is within +/- 0,02gr. A VTF change any larger will alter the vertical cantilever deflection enough to dwarf the 1-2mm VTA/SRA change.
Best,
Frank
Thanks, I will experiment with my digital scale to see what the VTF change is when I alter the VTA and attempt to hear the difference.
Hi Sean,
Congratulations on getting the LT arm installed!
Did you get the silver wire version or the copper wire version?
(mine and John's are the silver wire).
Arnie
Congratulations on getting the LT arm installed!
Did you get the silver wire version or the copper wire version?
(mine and John's are the silver wire).
Arnie
Hi Myles, I traded in my Reed 3P towards the Schroder LT. I still have my Reed 3Q on the back.
Hi Arnie, I went with the silver wire option. It is incredibly thin gauge wire. It must have been a real pain for Steve to wire, but it sounds great.
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This arm is amazing! It's so much more transparent to the source. Makes me want to listen to my whole vinyl collection again to hear how it sounds through this arm.
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