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VTA and HTA overhang

I was adjusting VTA on my tonearm tonight and out of curiosity decided to check how it effected the overhang according to my MINT LP protractor. To my surprise, very small changes to VTA on my 12" arm are quite noticeable when trying to align my stylus to the arc on my alignment protractor.

My question is to all of you who change VTA for each LP. How do you compensate or adjust for the resulting change in Horizontal Tracking Angle (HTA) or overhang each time you change your VTA setting?

Besides the hassle of adjusting VTA for different LPs, this is another reason I don't fuss with VTA once I have found a good setting for the majority of my LPs. I wonder if those who attribute sonic differences to VTA changes are not also hearing slight changes to alignment which surely effects the sonics.
peterayer

Showing 2 responses by tketcham

tketcham
291 posts
 
Theo, adjusting for differences in record thickness (weight) is exactly what I do using a Herbie's "Donut" mat. I use a 0.5mm mat to compensate for the thinner 120g-150g LPs. Actually, I'm compensating for the heavy 180g-200g LPs that I started purchasing a few years back; I noticed that SRA was changing slightly with the thicker LPs. So now I set up my cartridge alignment and tonearm height for proper SRA using one of my best 180g LPs (even thickness and flat) and then use the "Donut" mat to raise the thinner LPs up off the platter. It's not an elegant solution like the VTA adjusters on some tonearms, but it works.

The 0.5mm mat was a compromise because it actually works for a small range of LP thicknesses. (Refer to chart below.) I tried using a 0.8mm mat for the thinnest LPs (100g-120g) and used the 0.5mm mat for 130g-150g LPs but found that dealing with two mats wasn't worth the additional benefit for the lightweight LPs. They comprise a minority of my LPs so I can live with it. I'd rather set things up to optimize for the majority of my records and the high quality heavy vinyl.

Thickness/Weight
1.00" / 100g
1.27" / 120g
1.52" / 150g
1.77" / 180g
2.02" / 200g

I found the "Donut" to be sonically neutral using it with a Gyro SE platter. I'm not sure about other platter materials and construction.

Regards,
Tom
tketcham
291 posts
 
Sarcher30, the mat I'm referring to is not the "Way Excellent" mat; it's the "Donut" mat found at the bottom of the Herbie's Turntable Mat web page. It's basically the elastomer wafer of the "Way Excellent" mat without the silicone foam base. The "Donut" is not intended to absorb vibrations so it's sonically inert for the most part. That's why I found it to be a good method to adjust for LP thickness and SRA on the Gyro SE.

Theo, I'm not familiar with the Linn 12 platter so cannot say if it will work the same as for the Gyro SE. But I will add that I also use a "Donut" on a Music Hall mmf-7 turntable, which has an acrylic platter, and the results are similar. The main difference is that I use a Way Excellent mat on the mmf-7 and it compresses slightly so I use the 0.81mm "Donut" to account for the compression.

Regards,
Tom
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