Kdbrink:
No mat is needed.
The Pedersen upgrade is designed specifically to cure a problem when using an SME arm with the Gyros. Check out the TNT reviews pointed out on Pedersen's website. You can try putting blue tack under the screws that secure the armboard to the chassis and see if it improves the sound before spending $150 on the upgrade.
FrankC
No mat is needed.
The Pedersen upgrade is designed specifically to cure a problem when using an SME arm with the Gyros. Check out the TNT reviews pointed out on Pedersen's website. You can try putting blue tack under the screws that secure the armboard to the chassis and see if it improves the sound before spending $150 on the upgrade.
FrankC