If it sounds 'great', everything is ok?

So far, many thanks to all of you for your time and effort in answering to my question. Which is acutally a question from a friend living 200 miles south. I have some knowledge regarding this topic (and 4 different tt's in operation) but I know you might have even more (knowledge). So, I am glad you are supporting me.

Special thanks to

@vonhelmholtz Since you are happy with what you have, why not ask if incorrectly setup tonearm/cartridge will damage a record?

@mulveling (....) if is sounds really good, it probably isn’t too far off the mark on anything. Maaaybe VTF and anti-skate can get into "you shouldn’t do that" territory without being overtly audibly bad. But VTF is super easy to check & re-check, and anti-skate should be applied sparingly. 

You might add some conditions, too:

• Does it remain good across the whole record surface, especially inner grooves?
• Does it retain clean playback at loud SPL (exposing feedback and rumble issues), assuming the owner chooses to enjoy those levels? Boy has that one bit me lately lol.

and @elliottbnewcombjr

As to the main raison of my friend's question. It appears that the tracking force he has applied is around 1gr higher than recommended in the user guide of the Ortofon MM Black. However, he measured VTF with a digital scale. And this not a good idea as his tt is a Cleraudio with magnetic tone arm.

Despite the 2.9gr the digital scale is showing, he says the sound quality is 'super' to his ears. I assume that the 2.9gr is an incorrect reading. I will recommend to use a basic analog scale ("seesaw" model) and to compare this value with the other one given by the digital scale.

If VTF is really way too high, vonhelmholtz's comment comes into play

If the sound quality is 'super' to my friends ears, is it possible that the VTF is far away from being correctly set? --> coming back to my initial question.

Best regards, eagledriver

@eagledriver_22

The Clearaudio magnetic bearing arms are far enough away from the VTF scale that it should not affect the measurement at all. However these arms are extremely sensitive to footfalls (or feedback) and require meticulous isolation to work well - but if you’re concrete slab they should be OK.

Yes, it’s perfectly possible the VTF is actually 2.9g and still sounds good. That might even be smoothing over issues with the magnetic arm (which I’m definitely not a fan of - especially the Concept and Clarify models. If he has a Magnify, that one is a hybrid and I like it much better). 2.9g won’t hurt anything in the immediate short term, but you really do want to verify and adjust that down to 2.0g max.

Most of these digital scales come with a 1 gm weight to use to check it's accuracy. Perhaps your friend forgot it came with one.

modern cartridge tracking 2.9 g ain't good. Can sound good now, however it needs to be properly checked, soon.

One of the criteria I look for is light tracking force. Less wear on both stylus and grooves, IF it can stay in the groove which is not always easy.

Shure's always went for 'trackibility', their last great MM was V15Vxmr, it tracked between 1.0 and 1.5, I used 1.25. Stiffest Ever: Beryllium cantilever with MicroRidge Stylus.

I looked sideways at my Beryllium cantilever and it shattered (I dropped it about 1").

AT440ml tracks 1.25

Current AT33PTG/II MC tracks at 2.0g

from Shure 1954 bulletin

"the downward pressure of the stylus tip on the record groove. The greater this pressure the greater the amount of friction generated between the walls of the record groove and the stylus tip. Increased friction naturally results in increased wear."

adding 1 gm over specs ain't good!

There are going to be opposing views on the dangers of high VTF. Some would say it's better for the stylus to remain firmly seated in the groove, even at a bit too high a VTF, versus being too light and risking mis-tracking, or even bouncing around in/out of the groove. 

If I found out I'd been running a cartridge at 2.9g for (say) a week by accident, I'd correct it but wouldn't sweat the "what ifs" about whether damage may have occurred. Quite frankly I'm surprised an Ortofon 2M could hit 2.9g without bottoming out, since they're already low riders by nature and have fairly compliant suspensions. 

FWIW Ortofon's high-end MC's are spec'd to track as high as 2.5g or 2.6g, and I think some SPUs may be even beyond that.