It Also Doubles As An Apple Peeler.

I agree with Albert's assessment. An overly complex way to try to solve a fairly simple problem. While they did accomplish their goal of separate horizontal and vertical effective mass components, they did so many other things that they mucked up the overall performance, and thus obscured the one good thing they did.

The TWL HiFi mod is based around the concept of separate horizontal and vertical effective mass components. But I do it in a very simple, effective way that allows people to do it on their existing tonearms, without much expenditure or effort. It works very well.

Too bad the Dynavector 507 wasn't better overall, because it might have had a beneficial effect on other tonearm designers to do better in the horizontal mass component.

Buscis2, as I'm sure you are well aware, there are always compromises in designs.

Also, "excessive" effective mass" can be quite relative, depending upon the needs of the cartridge being used.

If you'd like my analysis of the DV507 in a nutshell, I'd say that it achieved its goal of maximum horizontal effective mass and minimum vertical effective mass. However, in the process, the geometry was severely compromised by the very short stub-tonearm which changes VTA-SRA dramatically with only small variations in record thickness or warps, the rigidity was compromised by the additional set of small bearings out there near the headshell, and the amount of wiring connections was compromised by need to bridge from the stub-tonearm to the main tonearm. Also, there were bound to be resonance problems by the multitude of various parts on the arm itself, but I have not done any vibrational analysis of this arm, so I cannot be sure exactly how much impact came from that. Also, back when this arm came out originally, there wasn't much consensus on whether wiring really made any difference or not.

However, they did have a great idea about making different horizontal and vertical effective mass, and that was something worth studying this arm for. I got the idea for my HiFi mod from that. I just didn't over-do the complexity, and made it easy enough for people to add on themselves to the popular Rega and OL tonearms.

I don't think you seem to be missing anything.