Discuss The Viv Lab Rigid Arm

@lewm 

Mijostyn’s position could be turned on its ear: you may be used to certain distortions created by overhung tonearms that you “like”. 

you mean like skating forces causing the TAE to change dynamically with modulation levels?

I spent another week listening back and forth between the "straight underhung Schröder" and my traditional Schick and the normal cues to TAE that I key on are not the same in both cases.  Gross TAE on the schick results in a harness to the high velocity peaks (think miles' muted horn) and that "harsh" sound is substantially less with greater TAE on the straight arm.  The other interesting difference is the larger that normal TAE on the straight arm seems to come at the cost of an overall higher noise floor.  This isn't immediately noticed until I return to the eerily black background of a properly aligned cartridge on the schick.  That said I am beginning to think that there is a reasonably good chance that since very few people are aligned anywhere near where they think they are, the nature of the Viv labs is akin to a conical vs. an advanced profile.  Incorrectly set up the conical wins.... properly set up the advanced profile takes over the lead by a large margin.  A 2° change in TAE has changed one of the best cartridges I have heard to one of the worst.  Change the microridge profile to a conical and suddenly you are "pretty good" for both setups.

dave

How did you create an underhung Schroeder? Does it have zero headshell offset too?

All of the offset is applied at the single mount screw.  The only thing preventing a 0° offset is the back of the cartridge hitting the armwand.   I made a shim to get the clearance so the cartridge could be set straight. 

I looked at the math and suspect the best setup for this type of arm puts the single null point about 80% of the way into the record.  I have found that the predicted distortions by the math need another factor of 2 added beyond the traditional weighting to match what I hear. I also suspect stevenson was on the right track since things get really ugly as you pass the second null and approach the lead-out groove.

dave

Do you detect a greater uniformity of any colorations, from lead in to lead out grooves?  That's what I thought I heard with the RS Labs, less in degree and fewer variations in sonic character, compared to a typical overhung tonearm, as it traverses an LP.  Which made it sound more like a good R2R playback.  (That's my best metaphor for it.) This effect was not probably as great as may come across in my writing about it, due to the fact that we must use words to describe it.

I could probably underhang my Sperling arm---like the Shroeder, it just has a bolt at the headshell to set offset angle. How large is your underhang with the Schroeder, Dave? With the RS Labs it was between 5 and 10mm.