It seems that VL12 tonearm effective mass is not specified on official product page or in the user manual. Is this a “secret” or just an omission? It would be great if Denon updates the technical specification sheet to include tonearm effective mass, as this value is required in order to verify tonearm - cartridge compatibility.
While I agree with having specs like this out there for turntables (W&F, overhang, offset, tracking error, etc), don’t forget to use a test record to check that resonance frequency. The headshell is just as important as the cartridge in this matter. If you are under-inertia for the compliance you can always add headshell weights to add arm mass and if you are over-inertia you can (sometimes) use a lighter headshell. Anyway, the VL12 arm is apparently stock Yahorng, and that looks like an SME clone like 1200 arms, so I assume similar effective mass distribution. Ditto with the old Denon DP-DJ151. The Numark TT 200/500/X line was a little less mass.
The use of a test record is always recommended, but before one decide to buy a certain cartridge it is good to know what to look for and make an educated decision based on some facts, like knowing the effective mass of the tonearm, to know if it’s a high, moderate or low mass and look for a high, moderate or low compliance cartridge. It’s not feasible to buy cartridges only to find their performance is not matched with the tonearm. If there are proven practices and rules ment to assist in making a good decision, why not take advantage and respect the work and experiments behind them? One can assume that a tonearm design based on Technics may be around 12 g, but it is always best to work with the specifications and put them to practice, because that’s why they were published.