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Koetsu surprise

I have to hand it to my wife.  Like many of us, I have always plotted and schemed my own system upgrades based on my interests and perceived best bang for the buck.  I have been concentrating on the analog front end for the past 4 years and have been listening to a lot more music.  I had been enjoying a Lyra Delos for its detail and upper register energy, a SoundSmith Zephyr Star for its amazing instrumental separation and full frequency balance and an Ortofon MC A90, that I purchased used of Agon.  Thought I was done with cartridges for a long time.
So when on the eve of our 20th wedding anniversary I received a little square box from her, I had no clue that she would gift me something for the stereo.  But there in front of me is a pretty little Koetsu Rosewood Signature Platinum!  
Its hard to describe the disbelief.  I had never considered a Koetsu.  My impression of them was that they were rolled off, romantic, old school cartridges that had been bettered long ago by the likes of Ortofon, Lyra and SoundSmith.  Never really read up on their cartridges given that their cheapest models were about as much as I would ever consider spending.  
Fast forward one month and I have put about 40 hours on the RSP.  From the first needle drop I was very impressed with the midrange presence and the utter ease and extension into the very highest frequencies. The bass did sound a little soft in the first several hours but has tightened up considerably.  It sounded its best loaded with 100 Ohms and mounted on my Mørch DP-6 with heavy brass headshell screws from SoundSmith.  I currently have it on my Jelco 750D with a Jelco Rosewood headshell.  
I don't think any of these arms are the best match but the RSP does sound quite special on all of them.  Just purchased a 40 year old Fidelity Research FR-64S.  Can't wait to listen to the RSP on this arm.  Any recommendations on the FR-64S/RSP combo are welcome.

This whole experience has taught me an interesting lesson about assumptions in our little hobby.  You just have to listen before you judge.  This is a quantum leap in musical enjoyment that would never have happened if left to my own devices. Anyone else have this type of experience?  First time you heard something that changed your mind about what you thought you knew about audio?

I married up!

128x128karl_desch
terry9
2,209 posts
 
After further consideration, I wonder if I might not have stumbled on the correct torque (for the mounting screws) instead. I will be getting a precision torque driver to sort it out, and will report back.
karl_desch's avatar
karl_desch OP
422 posts
 
It will be interesting to compare the FR-64S to the damped metal tonearm Jelco 750D.  I plan to use my ears. 

@terry9 I love that feeling when a little adjustment work seems to pay off. How difficult is the trans-fi to adjust?
terry9
2,209 posts
 
VTA is very easy. The rest is fiddly - then again, it costs $1k instead of $10k.
larryi
3,715 posts
 

I wondered about whether something else, like the torque on the mounting screws, had also changed.  I have my doubts about whether a small improvement in overhang would result in a big change in sound.  Also a change in overhang would make the sound better for certain parts of the record and worse for others rather than provide a uniformly superior sound.

As for the advantages of linear tracking arms, there are MANY theoretical pros and cons.  Some tone arm makers think that most linear tracking arms are actually worse at maintaining perfect tangency.  That is because as the stylus/cantilever move inward the arm resists moving more than would a pivoted arm.  The arm resists moving laterally more than conventional arms because they tend to have high mass in that plane of movement and because of the loss of the mechanical advantage of a pivot (it is easy to move something around a pivot, much harder to move the entire arm laterally along the air bearing tube, even if friction is minimal).  This resistance means that the cantilever is more inclined to being forced out of position (bending inward) with linear arms.  Obviously, the short arms on linear trackers can be made very rigid and less prone to ringing, but, there are arguments as to whether the lack of a conventional pivot prevents vibrational energy from being drained away and dissipated properly.  I don't know if these theoretical claims are true or not; I've heard nice reproduction from linear arms as well as conventional arms and cannot attribute differences to particular design elements.  To me, having noticed how small VTA changes affect sound, I am also concerned that the short arms on most linear trackers would result in larger shifts in VTA for different record thickness than is the case with a longer arm.

There are pivoting arms that take advantage of the "Thales" circle geometry to maintain tangency (also no skating), but, these are expensive, complex, and most require additional arm pivots and parts (added friction).  Some examples are the Thales arm, Schoeder LT, Funk Firm AK-1, and the Reed 5P (the Reed avoids extra pivots that the stylus/cantilever must move by using a motor controlled by a light sensor to pivot the tonearm base to maintain the tangential geometry). 

terry9
2,209 posts
 
Quite correct, Larry. I later realized that the effect might be caused by torque. When I get my precision torque driver I'll sort it out.

My posting was ambiguous. I was not adjusting overhang, but offset angle - which, of course, should be 0 for a linear tracker. Overhang is not really the issue with a linear tracker; one is after tangentiality, which can be set very precisely, even for a cartridge like the KRSP, with its invisible stylus.
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