Teach me about cartridge 'retipping'

Remember Technics best cartridges, this is one of mine under macro lens. Technics made the lowest possible moving mass MM cartridge (Boron Pipe cantilever). See why it’s better.

According to this Technics research:

"Somewhere in the high frequencies, every cartridge has an undesirable resonance point. Undesirable because there the frequency response curve climbs a sudden peak. If that peak is in the audible range, your records sound not as intended. That resonance frequency is determined by the total effective moving mass of the vibrating system - the summed masses of the diamond stylus and, most importantly, the cantilever and magnet, etc. To shift that harmful resonance frequency up into the high supersonics, the effective moving mass must be reduced to the lowest possible minimum. Also, too much effective moving mass increases the mechanical impedance, thereby negatively affecting the cartridge’s tracing ability."

Retippers can’t do anything like that, they don’t even have an access to those cantilevers, they are not available today (boron pipe, beryllium). What they can do is to buy what’s available and install it. Or they can glue a new tip on old cantilever, but glue will add mass etc. Re-tip or rebuild is a compromise, most likely degradation of the very special cartridge (if you have a very special one). This is why a very special cartridges must be shipped back to the manufacturer for rebuild or upgrade with a new one.  

fair points and perspectives so far - thank you

i should have been more precise to distinguish a retip from a rebuild... the difference is of course meaningful, thanks for pointing that out chak...

appreciate other comments that more experienced folks than me may have - am sure lewm, raul, mc and many others will chime in before long

All you need to know, explained well by Jonathan Carr (Lyra) on this forum long time ago, I will just copy paste here again: 

  "Changing only the stylus will alter the sound less than if the cantilever material is changed. When a cartridge is designed, the designer will consider the moving mass (sum of the stylus, cantilever and coils), the resonant character of the cantilever, and the (sonic) propagation velocity of the cantilever (affected by the cantilever's mass and rigidity), then choose the suspension and dampers accordingly. If you change the cantilever material, you are effectively throwing the original designer's calculations away. There is much more (far more than what I have written above) to rebuilding a cartridge than affixing a new stylus or altering the cantilever. In over 30 years of involvement in the phono cartridge industry, I have not seen one retipper who has presented the entire story, who has effectively said "Here are the all of the considerations. Here are the cons as well as the pros. Make a wise choice that is best for you" ... " (J.Carr, 2013)

I have bought a couple Grace F9 retips from Peter Ledermann - they work wonderfully. 

Your actual experience then is quite good. Yet we have pictures trying to create the impression that because there's a lot of glue it must be a sloppy job. At least that seems to be the impression. Always hard to tell with innuendo. 

Ledermann has a whole career built on developing and improving phono cartridges. If you want to learn about cartridges you could do worse than to watch the videos he has up on Soundsmith and YT.

Here for example is a fascinating discussion of jitter, (vibration and resonance in all the different parts of a cartridge) https://www.youtube.com/watch?v=WmwnN_T_wW8 Just the first few minutes should be enough to understand anyone posting pictures of glue is probably missing the big picture. Tracking a record groove sets in motion a complex pattern of vibrations in every part of the cartridge. The first point of vibration is the stylus itself. One might think its the stylus/cantilever attachment point. That seems to be the reason for the pictures. If so its misleading.

The stylus itself is very small but the tip of the stylus, the actual contact area, is microscopic. The stylus itself is bound to vibrate. The better the stylus is supported above the contact point the less of the stylus there is to wobble and flex around.

Now look at those photo's again. It would be super easy to put a blob of glue on there and stick the stylus into it. If that's what it was I'd be appalled. But instead what we see is glue perfectly applied in a smooth curve from as low on the stylus as it can go to as far out on the cantilever.  https://www.sound-smith.com/sites/default/files/BO-CL1a.jpg
This can't be by accident. Can't prove it, but watch a lot of Ledermann, try and tell yourself this was an accident. Try and tell yourself its anything other than Ledermann building a bunch of these things and figuring out by trial and error this is better than OEM.

Compare that now to OEM. https://scontent-arn2-1.xx.fbcdn.net/v/t1.0-9/119490585_4737129112971885_4613339876402529386_o.jpg?_... Notice that not only is the stylus itself not supported very close to the contact area, but the whole thing is projecting out much further from the cantilever. That's a big drawback, because the further it projects out the more mechanical leverage it has to put torque into the cantilever.

This would explain why your experience was, "They work wonderfully".

Watch a bunch of his videos. There's a lot to learn.

If you're impatient, or just want a terrific teaser how good his jitter video is
https://youtu.be/WmwnN_T_wW8?t=1220

This subject has been done so many times it is now flat as a pancake.  There are undeniable facts: If you have an original vintage cartridge, the suspension is old.  That per se may affect compliance and sound quality.  If it is NOS (never ever been used), then in my opinion it is even more likely that the suspension will be problematic.  Not to say it won't work and sound very very good, only to say that you cannot know how it sounded originally.  So, why the big fuss about re-tipping?  If you re-tip, don't expect original sound quality unless you go through the manufacturer, who usually will just be giving you a replacement new cartridge, for big bucks if MC type.  If you use an aftermarket re-tipper, then what you've got might sound wonderful but probably not like the original, and so what, if you are otherwise pleased?  Case in point, I own both an original Grace Ruby (sapphire cantilever/elliptical stylus) and a second one that was re-tipped by SS with their sapphire cantilever and OCL stylus.  I have often listened to them both in sequential order.  The SS re-tip version sounds better but not like the original.  I am happy either way but I use the SS re-tipped version much more often.  You can't have your cake and eat it too.  You can't go home again. What's past is prologue.  Etc.