Fact or misinformation?

No.

The situation where damage can occur is playing a stereo record with a mono cartridge that has "normal" lateral compliance and little or no vertical compliance.

dave

The big difference between a mono cartridge and a stereo cartridge comes down to noise pickup.  A true mono cartridge has the coils oriented to only pickup info in the lateral direction whereas a stereo cartridge is oriented with the coils at 45° to pick up info in both the lateral and vertical direction.  If converted to mono at the cartridge, the phasing of the stereo coils is such that the lateral info sums and the vertical info is nulled.  this null only becomes perfect if the info in the vertical direction is identical in both channels which never happens in the real world.  If the summation to mono is done by a mono switch this noise cancellation is less. The net result of this is since a mono record has only noise and zero musical content in the vertical direction,  a true mono cartridge can be much quieter in the groove than a summed stereo cartridge.

There is vertical compliance to keep the tip in the groove and handle record warps. Just higher compliance laterally. No vertical compliance means the stylus bounces in the groove from record warps.

yes... and interestingly enough the choice of the day was to use a rectangular cantilever cross section with a high aspect ratio to put all of the rigidity in the lateral direction.  The  flex of the cantilever in the vertical direction is what dictates the compliance and as you mention, it is a much lower value than the lateral number.

dave

But either way its a compliant diamond sliding through wiggles. A stereo needle will simply pick up the exact same movement on both channels.

I do not see how this will damage anything.

It comes down to whether the playback cartridge has vertical compliance or not.  In the pre-stereo days of mono cartridges had drastically lower compliance in the vertical direction than in the lateral direction since that was the only required direction of movement.   When Stereo was introduced the mono information was kept lateral and the stereo information was encoded in the vertical direction and the coils rotated to 45° so each channel could read both.  This means that you still get the common lateral component to each channel but different vertical components.  The compliance is what allows the diamond to move freely in all directions.  When you playback a record with vertical information with a  cartridge with no vertical compliance, suddenly a battle ensues between a diamond backed by the effective mass of the tonearm and the part of the groove trying to move the diamond in the vertical plane.  Simply put.... something has gotta give.  The Denon 102 is an interesting cartridge since it is one of the first mono cartridges with vertical compliance in line with the horizontal.  It essentially has lateral mono coils and a stereo suspension.  This was needed so broadcast playback could go back and forth between stereo and mono cuts without changing cartridges.

dave

Lew,

I agree that a mono switch helps.  The big thing it does is converts all the noise to a mono signal since having mono music and stereo noise is very distracting.  All of this based on the evil premise to some that you are listening to mono in the "sweet spot" of a stereo setup.

dave