Playing 7" singles - raising the platter slightly

Having a fairly large number of 7" 45 rpm singles I was wondering if anyone else had given some thought to VTA on these things. I am assuming they are cut, like LP at a very slight angle to the perpendicular. LPs are cut at, on average 92°
So, with the help of a digital microscope and some nifty software, I set up turntable and stylus to hit a 160 gm LP at exactly 92°
Which also works well for 120 or 140 gm pressings and 180 grams.


However, 45 rpm singles are thin. Some more so than others.
Styrene singles are really pretty thin.

So I would assume raising the platter just under a millimetre or so would improve the sound.
Sure enough, cutting a very thin circular plastic shim and putting over the spindle under the platter, thereby raising the platter sightly seems to improve the sound.

Has anyone else tried this?

 

I think that when you raise the platter with the shim the result is unbalanced and will cause needless wear to the spindle shaft wall. Depending on the design of the spindle, the shim can also raise the platter just enough to prevent the thrust plate at the lower end of the spindle from making contact with the bearing surface. If there’s a sub-platter, the end result with a shim will still affect the balance even if the shim is perfectly flat and plane. Basically, the shim ruins the design geometry of the drive system and bearing.

The simplest thing to do is to use a slightly thicker platter mat. They’re inexpensive. For best results when playing very thin 45s, use a thicker platter mat made of the same (or similar) material as your regular mat.

 

The difference in thickness would change VTA less than one degree. Why bother ?

 

Read the first post:

 

I agree with Agitater. Just get thicker mat. I have Rega turnatables. The stock mats are 3mm thick. I have a 4mm mat for this very reason. I'll admit, I don't swap it that often. But if I'm going to do a more critical listening session, like comparing pressing, the thicker mat goes on to keep things fair. Changing the VTA on a Rega isn't all that easy. I do have Michell VTA ring on my P3, but, it really can't be used on the fly. It just makes setup more precise. And my P5 has the new 3 point pedestal. So I'd have to swap shims. The mat takes seconds to swap out. And the OP has to remove the mat to shim the platter anyway. My 4mm platter is a different color than the stock mat, so I can easily tell which mat is being used.

 

I've tried something similar, using a "mat" cut from the thin cardboard of a Marie Callender frozen dinner box, one and two of them, placed under the regular rubber mat. There was no difference that I could tell, so I do not bother doing that.

 

45's and some platter mats can be a dangerous combination.

Years ago I transferred a friend's 300 count collection of rock & roll 45's he accumulated growing up in the UK. During the process, the tylus slid off of one onto the mat (felt) and yanked the stylus tip from the cantilever.

Not wanting to have that happen again, I substituted a Platter Matter. Guess what - it did happen again.

Ever since then, there has been no urge on my part to use anything but the mats turntables left the factory with.

My logic says that manufacturers addressed this possibility when they equipped their tables with the mats they did.

 

Yikes!!!

OK, point taken.

 

It seems to me any plater mat material would be dangerous to a stylus that slides off of the record, whether it’s stock or aftermarket, right? I’ll admit to being a little nervous any time I cue up a record that is smaller than the platter, for this very reason (thankfully I’ve never missed...).