Ortofon MC A90 Cartridge VTF

Norm,

my quest is only what sounds most real....in all seriousness. i don't have any pre-concieved notion on VTF. it either sounds best or it does not. i do think that only over time and open-minded listening and experimentation can the most ideal VTF/VTA be found.....and even then as the cartridge suspension softens over time these points can change.

i would say that with a new cartridge like the A90, initial break-in should be done in the recommended range, in this case 2.0--2.5 grams. with this particular A90 after about 25 hours on it i did do some experimantation and found 2.20 grams to be the best. but now there is 120 hours on that same cartridge.

we (Steve Dobbins, Jonathan Tinn and myself) had listened for awhile with the Garrard/Reed/A90 (with 120 hours on it) at 2.20 grams VTF. Jonathan felt that overall it was a bit sluggish and lacking 'sparkle' on top and suggested that we try to get it better. Steve was doing the adjustments and all three of us were listening. first Steve lowered VTF, it was better. then lowered it again, better. this cycle was repeated three or so more times. finally it got a bit thin on top, so we went back to the previous spot. better. then went lighter, worse. so back to that spot. now we worked on VTA. we went higher in back...worse. back to the same spot. better. then lower. worse. so back to the same spot. better. then we listened to some different cuts. it sounded great; amazing detail, body, open on top, powerful, articulate bass. then we measured. 1.56 grams. we were all taken aback.

regarding the Shindo and VTA. IMHO tt's don't have VTA, arms and cartridges have VTA. not that Shindo might not recognize that VTA can be very critical, but a particular cart and arm won't have different VTA on different tt's. other forces would account for different VTA's....degree of cartridge breakin, actual VTF, quality of set-up, degree of anti-skate. ambient conditions...etc. etc.

as far as overhang, VTF and VTA; they are somewhat interactive; howvever i am skeptical that overhang would change enough after 40+ hours on a cartridge (of suspension softening) to bother with messing with. it would be nanometers. and VTF will change VTA and SRA more than actually raising and lowering the arm a milimeter. the Reed 2P arm has a lever which allows for a 10mm range of 'on-the-fly' dynamic VTA adjustment which is great to hear tiny VTA adjustments....which we used.

Mike, yes by having everything fixed the Shindo minimizes what needs to be adjusted, including overhang and tracking weight. I just remember the old Shure tracking test records where you sought the lowest tracking weight before mistracking.

While I concede that we are talking about fractions of a degree and of an inch, I still expect that changing tracking weight varies both. I guess I will see once I get the Ortofon mounted and running.

Mike

It would be interesting to see how much of the differences are tt/arm dependent vs cartridge suspension differences. Will you try swapping the cartridges to uncover what is leading to the very subsatntial differences in vtf?

Andrew

Hi Andrew,

Great question about VTF changes from one arm to another using the same cart. Mike had wondered the same thing during our trials. The A90 I had at Mike's with about 40 hours of use, was most happy on the Reed at 1.92 g. The same cart was installed on a Tri-Planar when I got home and the sonic sweet spot for that combination was 2.25 g.

Steve

Vetterone, when you say "sweet spot" you seem to suggest that you could go lower but that the sound was not as good. Would the A90 in the Tri-Planar track at a lower tracking weight, but not sound as good?

I guess I am old guard. I set everything up accurately including the manufacturer's recommended tracking weight. Then I reduced the tracking weight downward until I got mistracking. Often I used the Shure record, but at least once I used an oscilloscope to look at the wave forms. Then I focused on the VTA.

Norm