Looking for ACCURATE SPEED turntable/tonearm combo

I'll echo what Mard51 and Johnnyb53 posted.

Buying on a budget means choosing between compromises. If speed accuracy/stability is primary then no inexpensive (< $4K) belt drive will provide what you seek. The brand doesn't matter. They're all audibly compromised when it comes to maintaining speed through musical transients because they all use elastic (stretchy) belts. When the stylus hits a big transient the belt stretches and the platter slows for some brief instant. Once the transient peak has passed the belt rebounds toward its original (shorter) length, speeding the platter back up again. If you're very sensitive to pitch variation this effect is audible - every time. It's more audible when such a table is A/B'd with a more speed stable design.

A good source would be the modded Technics 1200 tables from KAB USA.

Take a look at the Galibier Serac. It's above your budget, but it's the lowest price table I know of that begins to do both speed stability and resonance control at high end levels.

Ketchup,

As Dgarretson said, transient-induced speed variations are unlikely to be visible with a strobe. Our strobe wouldn't pick up most of them, though it's more resolving than the KAB (Paul built it in a CAD program). We're talking about time shifts lasting only as long as a single beat.

MarkD51,
For better or worse, we don't have to listen intently or "try" to hear this. We just do. We don't find this sensitivity diminishes our enjoyment of music played well. I believe it may enhance it. We have thousands of LP's we enjoy hearing repeatedly, though I admit we've heard many othes we'd gladly use for driveway resurfacing material. ;-)

BTW, a heavier platter does not eliminate speed variations from stylus drag. Newton forbade that when he discovered the laws of motion. All else being equal, a platter with higher rotational inertia lowers the frequency and reduces the amplitude of speed shifts. But it can't eliminate them.

Whether they're audible is up to the ears doing the listening. We hear them despite our 35 lb. platter if something's not right, or when testing an inferior belt material. The improvements we described and others confirmed on the "Upgrade for 1/2" mylar belt" thread demonstrate this beyond any doubt. Most users on that thread have heavy platters, but they have no difficulty hearing differences in speed stability made by a belt change.