BREAK-IN
Arthur's U2 needed many hours before settling in. Ours knocked our sonic socks off on the first play and changed very little after 10-15 hours. In other words, YMMV.
The molecular bonding characteristics of elastomers used in cartridge suspensions produce highly random behaviors. Specific predictions have little validity.
VTA/SRA
Agree with Arthur that the VTA/SRA sweetspot is wider, as noted in our review. Tweaking for each LP is still audibly beneficial, but it's less necessary because the performance dropoff if you don't bother isn't nearly as great. The sweet spot for the U1 was razor thin, the U2 has broader shoulders.
VTF
Any finding that Arthur's U2 needs a little more VTF than his U1 should probably be ascribed to individual cartridge differences, not necessarily to the difference in models. My experience was actually the opposite.
I've had about 15 U1s in my system (my own 3, several belonging to friends plus multiple customer cartridges sent to me by Mehran for inspection). No two of them needed exactly the same VTF.
As for how to set VTF, I'd play the cartridge at some safe setting, say 2.0g or so, until you're comfortable that the cartridge has settled in.
After that, my procedure is the same for any UNIverse (and most top level cartridges):
1. Reduce VTF in .05g increments until you find the mis-tracking point on your toughest-to-track passages.
2. Nudge VTF back up in .01g increments until mis-tracking ceases; HFs should sound clear, open and non-fuzzy.
3. Nudge VTF further up in .01g increments until LFs and dynamics sound solid.
4. Nudge VTF further up in .01g increments until HFs and/or micro-dynamics begin to sound a bit muffled.
The range between Steps 2 and 4 is the acceptable VTF range for this cartridge, with Step 3 being optimal...
- on this day
- in these weather conditions
- for this LP
Change any of the above and the VTF range and optimum will also change. Tweak as necessary, depending on what you hear and how much it bother you to be off of "perfect".
Arthur's U2 needed many hours before settling in. Ours knocked our sonic socks off on the first play and changed very little after 10-15 hours. In other words, YMMV.
The molecular bonding characteristics of elastomers used in cartridge suspensions produce highly random behaviors. Specific predictions have little validity.
VTA/SRA
Agree with Arthur that the VTA/SRA sweetspot is wider, as noted in our review. Tweaking for each LP is still audibly beneficial, but it's less necessary because the performance dropoff if you don't bother isn't nearly as great. The sweet spot for the U1 was razor thin, the U2 has broader shoulders.
VTF
Any finding that Arthur's U2 needs a little more VTF than his U1 should probably be ascribed to individual cartridge differences, not necessarily to the difference in models. My experience was actually the opposite.
I've had about 15 U1s in my system (my own 3, several belonging to friends plus multiple customer cartridges sent to me by Mehran for inspection). No two of them needed exactly the same VTF.
As for how to set VTF, I'd play the cartridge at some safe setting, say 2.0g or so, until you're comfortable that the cartridge has settled in.
After that, my procedure is the same for any UNIverse (and most top level cartridges):
1. Reduce VTF in .05g increments until you find the mis-tracking point on your toughest-to-track passages.
2. Nudge VTF back up in .01g increments until mis-tracking ceases; HFs should sound clear, open and non-fuzzy.
3. Nudge VTF further up in .01g increments until LFs and dynamics sound solid.
4. Nudge VTF further up in .01g increments until HFs and/or micro-dynamics begin to sound a bit muffled.
The range between Steps 2 and 4 is the acceptable VTF range for this cartridge, with Step 3 being optimal...
- on this day
- in these weather conditions
- for this LP
Change any of the above and the VTF range and optimum will also change. Tweak as necessary, depending on what you hear and how much it bother you to be off of "perfect".