As you no doubt know, many turntables are greatly affected by the surface they're coupled to. I'd suggest you try situating your turntable on an isolated plinth that sounds good and then you'll take the sound of the rack shelf out of equation (more or less.) Personally, I like the sound of the 3.5" thick maple plinth I've had under my previous VPI turntable and the current Acoustic Reference I have. The heavy maple plinth sounds better than any rack surface I've tried.
