Parallel? How do you set the VTA?


Silly question, but how do you guys determine whether your tonearm is parallel to the record surface? I had my tonearm set up happily for months, but recently started messing around with the cartridge alignment and the VTA, and I'll be damned, but the folded index card method gets me nowhere now. Even with adjustments I keep getting the same visual effect. Happily my ear tells me when the setting is off, but as a base, how do you determine conclusively your tonearm is parallel? For reference, I have a VPI Classic. Thanks.
actusreus
I have a screw gauge that slips under the arm lift.
1/4 turn of the screw equates to 1/1000 of an inch.
I can hear 1/1000 of an inch like night and day.
In reality you are only getting near the zone with bubble levels.

But then what about the cutterhead angle, which varies by record.
So the only way is to listen and dial in each record and using dial calipers to measure and record the height for each record.

Any takers ?
Dear Frogman: Of course and agree with you: what will define where the tonearm will be parallel or not is at wich VTA/SRA the cartridge signal quality performance is the " best ".

Now, due that the analog medium/LP is so imperfect that VTA/SRA is changing every groove on playback as is changing VTF and overhang too.

That Fremer 92 degrees could means almost nothing because that could be only in theory but on playback always is changing. Ok, could be a point to start but nothing to " die for ".

My advise is to have 6-7 differnt LPs that we know in deep and that can help us as a testing tools to the cartridge/tonearm overall set up. These works have to be make it by ears. At the end our cartridge SRA set up can coincide with those 92 degrees but it is not important that that happen but that what we are hearing LP after LP has the best quality performance we can achieve in our audio system.

Unfortunatelly because the whole analog imperfections medium many subjects that gives us the theory can't be achieved during LP playback.

Regards and enjoy the music,
R.
Brf-
How does this paradigm deal with the different thickness of records? Within each record the stylus will rise and drop, how should we account for this change in sra?

We will never agree on a solution until we agree on what the target is. More complicating, a moving target everytime we change records.
Zenblaster, it is all about the “best” compromise. You set the 92 degree sra for an average thickness, etc. Variance in record thickness, difference in cutting head angles, will affect the sra but not to the extent that it will significantly change the tonal balance of the cartridge. I would hazard a guess and say that 99% of all audiophiles do not adjust VTA to compensate for record variances. Also, some stylus tip are more sensitive to sra than others.
Dover,

I've been doing exactly that for 10 years, except that I've no need for calipers. The height adjustment scale on my tonearm provides precisely repeatable settings.

The optimal arm height for each LP is recorded on a sticky note on the record jacket (and updated if I change cartridges). Setting arm height for a re-play takes only seconds.

Set and forget? Nope. Set and remember works better for me.