Tonearm, yes tonearms for record players.

[Angsty]

Moving way down the turntable spectrum, the VPI Traveler arm had sapphire bearings until there were too many returns due to owners rotating the counterweight improperly and breaking the bearings. They eventually switched to stainless steel bearings, but several owners have said that the tonearm did not sound as good after the change.

When is sapphire better for tonearm bearings than stainless steel?

 

[JP]

@Frank Dernie here's 50Hz, 100Hz, 1kHz, 3kHz, and 10kHz:

 

[Frank Dernie]

I see every arm resonance and maybe other parts of the record player buzzing away. I have no explanation as to why these would be excited so strongly because of a chip on a ball in a bearing.

I do not have detailed knowledge of this arm design. The one I know best (I stopped doing record player engineering in 1976) was the SME 3009 improved which was criticised for having a knife edge bearing which therefore was "inadequate".
In my measurements the only thing producing any notable spurious cartridge output was the removeable headshell fixing, and how bad this was depended on how tightly it was fastened. Nothing even remotely like this.

One big difference would be the cartridge damping. The biggest shortcomings of the record player as a vibration transducer, since that is what it is, is that the damping is in the wrong place for copybook function.
There has to be damping to prevent too much infrasonic amplitude at resonance, the output at frequencies between DC and 2x the natural frequency are spurious, but the correct place for the damping is between the cartridge body and disc surface, which is impractical, only Shure produced cartridges like this I believe. If you put the damping where it is traditionally on cartridges it "short circuits" the suspension at high frequencies and shunts a lot of energy into the cartridge body and hence arm.
The extent to which this happens will depend on the type of damping. Cartridges do not contain classic dampers but blocks of polymeric material. How this behaves as frequency rises will be extremely dependant on the type of polymer and its age.
The only way I can think of that this much excitation could get to the arm from the record is through a characteristic of the damper in the cartridge, and this tends to agree with this new data which shows it gets worse and worse with frequency (high damping shunts more energy as frequency rises).

I am not familiar with the details of Supex cartridges and we didn't have anything like that for testing, but at the time Linn were slagging off SME for using knife edge bearings LP12s were being used with Supex cartridges and Grace arms and I believe Supex made the early Linn branded cartridges.
Maybe with such a cartridge enough energy is shunted into an arm to cause vibration levels above 1g at the bearings and that is what Linn found? I do think Linn knew a lot about how record players worked that they kept to themselves to avoid the competition getting free R&D.

I would never have expected this and, as somebody very aware of where the damping should be for correct transduction I tend to prefer the Townshend solution, but getting a cartridge with minimal damping is a problem, Decca/London perhaps, or the Shure solution which has limitations of its own.

Really this looks to me like the worst aspect of a record player as an accurate transducer coming home to roost!

 

[JP]

Spec'd VTF for the Supex is 1.8g, so it'd seem it's a bit on the lower side for compliance. It's also not my sample, so can't assess the health of the suspension.

 

[anmpr1]

...but the correct place for the damping is between the cartridge body and disc surface, which is impractical, only Shure produced cartridges like this I believe.

...LP12s were being used with Supex cartridges and Grace arms and I believe Supex made the early Linn branded cartridges.

In my measurements the only thing producing any notable spurious cartridge output was the removeable headshell fixing, and how bad this was depended on how tightly it was fastened.

As to why other makers didn't offer shock damping at the cartridge edge? Possibly a patent issue with Shure, but that patent has had to have expired years ago. Some folks claimed that the damped brush 'degraded' the sound, but I never experienced that.

Even earlier was the Stanton/Pickering brush. It collected dust, but was not damped--it was just hinged, and didn't act as a precision shock absorber like the Shure.

Discwasher company offered an add-on damping device that connected to the headshell, as an outrigger, but from what I could tell it never made much of an impression with anyone.

The Townshend turntable featured a silicon trough attached to the front of the arm, across the arc of tonearm travel, providing damping.

I've seen Linn decks using the rather low mass G-707 arm, which seemed to me to be more suited to higher compliance MM cartridges. Grace sold their own line of MM cartridges which the company claimed mated well with the 707 arm. Grace also made higher mass arms (several were oil damped at the unipivot) that might have been a better match for the typical low compliance Japanese MC, but you didn't see them often--at least here in the US.

As a cartridge changer I always gravitated to plug in headshells for convenience, although some claimed they were not as 'sonically' wholesome as fixed designs.

 

[Frank Dernie]

Spec'd VTF for the Supex is 1.8g, so it'd seem it's a bit on the lower side for compliance. It's also not my sample, so can't assess the health of the suspension.

The vtf has nothing to do with it, it is entirely caused by the damper. By 2x natural frequency there would be zero energy transferred to the arm if the cantilever damping was zero. Any energy getting to the cartridge body from the cantilever above this frequency is being shunted there by the damping, the higher the damping the less accurate the transduction in band.

 

[Frank Dernie]

As a cartridge changer I always gravitated to plug in headshells for convenience, although some claimed they were not as 'sonically' wholesome as fixed designs.

The SME type is not so much "not wholesome" as inducing audible levels of vibration to be picked up.

 

[mhardy6647]

I am too lazy to go back to look (sorry)! ... but any of y'all interested in arms and headshells and resonances and whatnot might want to check out Alex Korf's blog. He has skin in the game -- but, from my perspective, he walks a rare and admirable line between the objective and subjective factors at play in the reproduction of vinyls rekkids records. His attitude also strikes me as healthier than average on the analog side of the fence.

http://korfaudio.com/blog

 

[Robin L]

Discwasher company offered an add-on damping device that connected to the headshell, as an outrigger, but from what I could tell it never made much of an impression with anyone.

I got one. Nowhere near as good as Shure's.

I've seen Linn decks using the rather low mass G-707 arm, which seemed to me to be more suited to higher compliance MM cartridges. Grace sold their own line of MM cartridges which the company claimed mated well with the 707 arm. Grace also made higher mass arms (several were oil damped at the unipivot) that might have been a better match for the typical low compliance Japanese MC, but you didn't see them often--at least here in the US.

They did---I had a couple, but sonically, they were no great shakes.

As a cartridge changer I always gravitated to plug in headshells for convenience, although some claimed they were not as 'sonically' wholesome as fixed designs.

There are so many other problems with LP playback. The ability to swap out styli or cartridges is more important than obsession with overhang and VTA. Though I never got to take advantage of the arm's potential, the SME III with the arm "wands", locating the connection point much closer to the counterweight, seemed like a good solution. My favorite arm for high compliance cartridges.

 

[JP]

The vtf has nothing to do with it, it is entirely caused by the damper. By 2x natural frequency there would be zero energy transferred to the arm if the cantilever damping was zero. Any energy getting to the cartridge body from the cantilever above this frequency is being shunted there by the damping, the higher the damping the less accurate the transduction in band.

I was using VTF as a proxy for compliance. A less compliant cartridge isn't going to transfer more energy in to the arm?

 

[Frank Dernie]

I was using VTF as a proxy for compliance. A less compliant cartridge isn't going to transfer more energy in to the arm?

No, but it is frequently wrongly stated that it will - static thinking in a dynamic system is often done but always incorrect.
In a seismic transducer by the time you get to 2x the resonance of the effective mass on the spring the mass becomes a "stator" ie it becomes stationary relative to the stylus from this frequency up, so the compliance is no longer active in energy transfer. This is in an idealised sensor. As soon as damping is added to reduce amplitude at the out of transduction band resonance this damping will shunt energy into the system, short circuiting the suspension and reducing accuracy.
I had thought makers would have found a material where the damping went down with frequency - unlike classic viscous damping - but in this cartridge clearly not! The worst excitation is at the higher frequencies.

 

[JP]

Makes finding a nicely pathological cartridge to test with a bit more of a challenge.

 

[Frank Dernie]

Makes finding a nicely pathological cartridge to test with a bit more of a challenge.

Looks like you've got one already!
I wonder what the data would look like with a Shure V15!

 

[JP]

I don't - that one isn't mine. Now V15's I have around a dozen, so can definitely check those out, but I don't have a misbehaving tonearm here.

 

[anmpr1]

Now V15's I have around a dozen...

Shure's damped carbon fiber brush was introduced with the Type IV. On my VxMR the brush damper went south. I don't know what type of liquid viscosity Shure used to provide the shock absorption properties, but after a while it could dry up. The Shure FAQ on their Website (a great source of info on Shures, and cartridge measurement in general) indicates that this was something that could possibly be expected, after time.

Shure also states that the elastomer material surrounding the stylus shank (cantilever) could 'dry out' causing the entire stylus assembly to fail. Then the only option would be a new stylus assembly (there was nothing to wear out in the actual cartridge body). But since Shure stopped all phono cartridge production some years ago, owners looking for genuine replacements are out of luck.

Aftermarket JICO styli have the brush, but I don't know if it is just hinged (like the Stanton device) or if it is truly damped. Otherwise, JICO diamond and cantilever assemblies look first rate and appear to be reasonably priced. I have no first hand experience with them.

 

[sergeauckland]

Shure's damped carbon fiber brush was introduced with the Type IV. On my VxMR the brush damper went south. I don't know what type of liquid viscosity Shure used to provide the shock absorption properties, but after a while it could dry up. The Shure FAQ on their Website (a great source of info on Shures, and cartridge measurement in general) indicates that this was something that could possibly be expected, after time.

Shure also states that the elastomer material surrounding the stylus shank (cantilever) could 'dry out' causing the entire stylus assembly to fail. Then the only option would be a new stylus assembly (there was nothing to wear out in the actual cartridge body). But since Shure stopped all phono cartridge production some years ago, owners looking for genuine replacements are out of luck.

Aftermarket JICO styli have the brush, but I don't know if it is just hinged (like the Stanton device) or if it is truly damped. Otherwise, JICO diamond and cantilever assemblies look first rate and appear to be reasonably priced. I have no first hand experience with them.

I bought a bare V15-V body then a Jico SAS stylus a few years ago, and that stylus came with a proper damper. The damper works exactly as it should, as I put the V15 in my EMT turntable which has a medium-high mass arm, suitable for the lowish compliance EMT cartridge. With the damper engaged, the LF resonance was very effectively damped, whereas without it, the stylus was flung about with gay abandon on my test records. Although I didn't persist with the V15 on the EMT, it did work well enough to be perfectly usable and showed the value of damping, properly applied and at the right place.

The SME method of applying damping near the pivot, I think is fairly pointless, and the Townsend method, I suppose is better than nothing, but will only work when the damping trough is rigidly attached to the baseplate that the turntable bearing and arm attaches to, not much use on a suspended turntable.

S.

 

[anmpr1]

I was using VTF as a proxy for compliance. A less compliant cartridge isn't going to transfer more energy in to the arm?

Mitchell Cotter, who was something of a phono guru back in the day, preferred MC designs due to cantilever suspension design. During the 'tracking force' wars MM cartridges tended to be designed for the lowest down force--the idea that a lower VTF would reduce record wear. To achieve this most MM incorporated flexible rubberized mounts.

Cotter claimed that this setup allowed the stylus to not only move up and down, and side to side as record groove modulations required, but also allowed the stylus to 'pump' back and forth axially, which caused an unwanted and unnatural FM distortion. MC designs (which were generally less compliant) held the cantilever rigid in the axial plane, typically using a very fine wire attached to the end of the cantilever, which was then rigidly fixed to the cartridge internals. Thus, the diamond in a MC design could move up and down, and side to side in a rotational arc, but could not pump axially, front to back.

 

[anmpr1]

I put the V15 in my EMT turntable which has a medium-high mass arm, suitable for the lowish compliance EMT cartridge.

EMT. For the man whose home cassette deck is a Studer A-80!

 

[JP]

Shure's damped carbon fiber brush was introduced with the Type IV. On my VxMR the brush damper went south. I don't know what type of liquid viscosity Shure used to provide the shock absorption properties, but after a while it could dry up. The Shure FAQ on their Website (a great source of info on Shures, and cartridge measurement in general) indicates that this was something that could possibly be expected, after time.

Shure also states that the elastomer material surrounding the stylus shank (cantilever) could 'dry out' causing the entire stylus assembly to fail. Then the only option would be a new stylus assembly (there was nothing to wear out in the actual cartridge body). But since Shure stopped all phono cartridge production some years ago, owners looking for genuine replacements are out of luck.

Aftermarket JICO styli have the brush, but I don't know if it is just hinged (like the Stanton device) or if it is truly damped. Otherwise, JICO diamond and cantilever assemblies look first rate and appear to be reasonably priced. I have no first hand experience with them.

I've seen a tech note somewhere, I believe from Shure, that tells you what viscosity of silicone oil to use for the damper. My samples that I've tries thus far have all been good.

The suspension elastomer doesn't bother me much as the biggest challenge there is finding a suitable material and fashioning it. The actual work of R&Ring it on their styli is rather easy.

The JICO doesn't feel damped to me. On the Shure you can easily tell there's a damping fluid or similar in the hinge, but on the JICO I can't feel anything. The hinge is also far less smooth on the JICO through its motion and feels loose. Last, I've measured the VN5MR SAS, and it has a predominant rising response that can't be tamed with loading. I also have a couple ruby, sapphire, and zirconia SAS here but I haven't bothered to measure them yet. IIRC I think I did measure the zirconia, and it was worse than the boron, but I'd have to go back and check.

 

[JP]

Mitchell Cotter, who was something of a phono guru back in the day, preferred MC designs due to cantilever suspension design. During the 'tracking force' wars MM cartridges tended to be designed for the lowest down force--the idea that a lower VTF would reduce record wear. To achieve this most MM incorporated flexible rubberized mounts.

Cotter claimed that this setup allowed the stylus to not only move up and down, and side to side as record groove modulations required, but also allowed the stylus to 'pump' back and forth axially, which caused an unwanted and unnatural FM distortion. MC designs (which were generally less compliant) held the cantilever rigid in the axial plane, typically using a very fine wire attached to the end of the cantilever, which was then rigidly fixed to the cartridge internals. Thus, the diamond in a MC design could move up and down, and side to side in a rotational arc, but could not pump axially, front to back.

Very aware of Cotter and a lot of his work. From the late 70's on, at least for the cartridges that have interested me, most of the MM have tie wires. I understand how the suspension elastomer on MC tend to be support perpendicular to the axis while MM are typically around the axis. I can't speak to what that'd equate to dynamically.