Adding a Turntable Mat


   I have an older turntable (Pioneer PL-530). Am the original owner. Have done a few things to keep this table operating as original as possible. Yeah, I know this isn't a high end table by any means. Rather than receiving a flood of advice on what tables are better, I would like to hear from someone who may have knowledge/experience with different types of table mats.
   My table has no VTA adjustment capability. The stock platter mat is rubber. Seeking minor/inexpensive tweaks and if a different mat may or may not provide any perceptible improvement. If it's inexpensive and provides no improvement....no problem.
   Here's my question.....For example...If I installed a thin cork mat, could that mat simply be placed on top of the existing rubber mat or should the rubber mat be removed first and then just use the cork mat? Remember, this table doesn't have VTA adjustment.
Thanks

jrpnde
To get your VTA right you need a high power microscope.  take the cartridge off and measure the stylus to the cantilever angle.  Then remount it and measure the cantilever to the record angle because the stylus is too small, it can't be done accurately.  That is the only way to get it right.

One high-end cartridge was 7 degrees off.  Far our of my adjustment range.  I put a wedge between the cartridge and the headshell and all is OK.

I think someone here suggested different mat thicknesses to vary the VTA. 

If you want a non-reflective mat, as I prefer, get a thin sheet of sorbothane.  It is very sticky to vinyl though, so cut a thing isolating layer of something so it won't adhere to the record.  That makes a huge difference in sound.

tksteingraber, Far as I can tell they have a couple dealers here in the US but none of them carries any stock in hand. So I order direct from Mark Baker at Origin Live in the UK. I would email and ask about shipping. Mine came with my Enterprise arm. The Enabler is so small it should go in a regular mail envelope, but Mark will know for sure. 
A rubber or sorbothane mat will make you think you’re solving problems, in reality, you’re storing energy, thus not getting best sound.
For the last thirty five years I've used my old VPI HW19 without a mat other than a few times I tried mats.  I prefer it naked.  I've already bought but haven't yet received a new Clearaudio Performance DC Wood tt.  I don't intend to use a mat either