MONO cartridges

Is it not the case that playing stereo-cut grooves (including mono material reissed the last 30ish years) with a "true mono" cartidge like a VRII damages the grooves? Caveat emptor!

Hi,
I spoke with a few people about Mono cartridges. Some say, they have a kind of hum with their Mono cartridges, no way to avoid it. But some have low efficient speakers, no problems but a few have 98dB++ designs, they told me, they think about special Mono Phonostages...
Any idea, is this hum based on design or manufacturer?

Syntax,
I am posting a reply that I made to another recent thread on the Shelter 501 mono cartridge.

06-10-09: Sabertouch
Davt,
I owned the Shelter II mono for a couple of months. It exhibited a low hum with the 3 high quality phono stages I own. Finally discovered it was a single coil design [not in specifications or description anywhere]. Install instructions were meager. It sounded pretty good even with the hum which was only there during quiet passages. Tried everything to get rid of the hum. Learned of another owner with the same hum problem.
Bottom line. Most of todays phono pre's have grounding designs which will cause hum with single coil mono pickups.
I bought a Lyra Helikon mono which has a two coil design and great instructions. It easily bettered the Shelter in detail, soundstage, realism, tick and pop resistance and dynamics. Quality is excellent.
The Shelter is good too and I would probably would have been happy with it if I could have found a way to eliminate the hum. In my research into the problem, I found not much is known about mono playback component compatibility in the vinly community since very few are sold.
Incidently, I was floored by how much better my mono lp's sounded with the helikon as compared to my very expensive and highly regarded stereo cartridges. To hear a Blue Note original from 1959 with a Helikon mono is an amazing sonic experience.
I don't know if the other expensive stereo cartridges which have been converted to mono output are better than the Lyra. They were originally designed for stereo output and not mono and have been converted to mono through internal wiring changes.
It is easy to find forum input on the Helikon if you dig a little. It appears quite a number have been sold. You can also find some good magazine reviews.

Sabertouch,
super. Thank you very much. You confirmed my thinking about that.

Has anybody listened to a Dorian Mono?