Ortofon A90 or Air Tight PC-1

I haven't heard the A90 yet, but Dertonarm hit the nail on the head. The thing that matters is matching playback stylus SRA to groove SRA, and a microscope can't help with that.

Groove SRA is different for virtually every LP you own, and you can't see it with any microscope short of an SEM. Even LP's of the same thickness have different groove SRA's. (Exception: unless they were cut on the same lathe with an identical cutting stylus set up to the same parameters - good luck finding that).

Therefore:

1. If playback SRA will be optimized for each LP, using a microcope to set some pre-determined angle is pointless. If I'm going to adjust until each LP sounds right anyway (and record that setting for replays) why waste the time?

2. If playback SRA will NOT be optimized for each LP, using a microcope to set some pre-determined angle is also pointless. For the "set and forget" user, this would serve no purpose except to satisfy OCD tendencies and earn their dealer some fees. If one can't hear or doesn't care about the sonic differences that groove-specific SRA makes, why take pains to set some pre-determined angle that bears little relationship to any particular LP?

The foregoing is especially true for styli with very fine contact lines, like the Ortofon Replicant. With such styli, the window for correct SRA on each LP is so narrow that a generic setting is useless. It won't make much sonic difference whether you're off by a hair or a mile.

Frankly, the microscope suggestion seems like a ploy to tie gullible owners to dealers. If the dealer is going to stand next to your table and adjust your SRA for each LP you play, fine. Having them do it in advance with a microscope (or any other tool) is nonsense.

@ Downunder,

Sorry to hear that you're dissatisfied with my suggestions to help set up your cartridge. I'm also sorry to hear that you're not willing to read up on the numerous articles that provide advanced insight into SRA optimization for all cartridges (not just the A90). If you are uncomfortable with the information being discussed here, then it might be worth it to inquire to your local Ortofon distributor about hiring a professional with test equipment to do it for you.

For the rest of the interested parties who DO wish to investigate the topic further, I would suggest checking the Analog Corner article from Stereophile Sept 2009 and June 2010 issues. They give some very excellent information on how one can use an inexpensive digital microscope to get a side-shot of the diamond and then to adjust the VTA so that the contact area can be aligned properly. The techniques discussed for SRA aren't rocket science - they can be performed in a matter of minutes once the USB microscope is set up and focused. It's even a possibility that you might find someone at your local audio society who is willing to let you borrow one.

Of course, one may also do this by ear, but as expected it does require tenacity.

Even though Ortofon recommends that you get the SRA to a value that sounds best with the majority of your records, rather than adjusting for each one, I don't see why one couldn't spend some time with a digital microscope and record the corresponding VTA settings for a 160gm pressing versus a 220gm (or the values in between, perhaps).

Since I'm rarely on these forums (as much as I love to chat about cartridges), anyone who has additional questions may contact me directly - ldorio@ortofon.us is my email address.

Louis/Ortofon

I don't see why one couldn't spend some time with a digital microscope and record the corresponding VTA settings for a 160gm pressing versus a 220gm (or the values in between, perhaps).

One could, but (as I posted just above) the SRA for one 160gm record is not the same as for the next 160gm record.

I've recorded optimal arm height settings on over 1,500 records from my collection. Tenacity, as you suggested. ;-)

Weight/thickness is a reliable guide to a starting SRA setting ONLY when comparing on to LP's on the same label, from the same plant, cut around the same time. Weight/thickness have no value for choosing SRA in a vacuum, so just knowing where X degrees of SRA is on a 160gm record is of little value.

@Dougdeacon, agreed, although you'd be pretty close if the record was mastered according to IEC standards.

Ldorio

I never said I had any problems with setting up the A90. I have read Fremers articles and it helped a lot (it seems TAS did not no?)

Out of 4 professional reviews, only Stereophile was overwhelmingly positive, which does not relate to my listening experiences. It would seem that most reviewers don't understand how to set the A90 up correctly.

I was looking for some more generic/systematic Ortofon recommendations on how to align correct SRA for the A90.

enjoy