Okay, here's another version of the question...
I have a VPI TNT IV, which came with a single idler flywheel, (not the extra three you sometimes see around the edge; apparently, there are quite a few versions of TNT). The base has three holes for the weird three-point idler mechanism but mine doesn't have it. The motor drives the idler flywheel, which is very heavy and has a larger diameter pulley than the motor, then another belt from the flywheel idler drives the platter round and round. I'm sure the idler flywheel is designed to both separate the motor from the platter, and with its weight, damp any transferred motor vibration and speed variation.
Since VPI got rid of the idler flywheel for later models, I've been toying around and did that, too..
So what happened? Did the world fall apart?
Honestly, I can't tell the difference. And without the idler flywheel, the whole turntable "package" makes a much smaller footprint. With and without the idler flywheel, I've been using the odd but yes-it-works-great piece of dental floss to drive the turntable platter. And the VPI SDS speed controller in both cases (the only way to get 45 RPM), so the only A/B difference is eliminating the flywheel idler.
The base it sits on is very heavy and damped, and it's using the stock VPI spring-loaded isolation/leveling feet which supposedly aren't the cat's meow but seem to work fine for me. The stock 12.5 tonearm with a Shelter 90X cart.
Anyone's thoughts? Has anyone else tried just simplifying the drive that way? It certainly looks more steampunk with the extra belt and idler gizmo, but simplicity is appealing. What intrigues me is this is essentially what VPI did in later models.
I have a VPI TNT IV, which came with a single idler flywheel, (not the extra three you sometimes see around the edge; apparently, there are quite a few versions of TNT). The base has three holes for the weird three-point idler mechanism but mine doesn't have it. The motor drives the idler flywheel, which is very heavy and has a larger diameter pulley than the motor, then another belt from the flywheel idler drives the platter round and round. I'm sure the idler flywheel is designed to both separate the motor from the platter, and with its weight, damp any transferred motor vibration and speed variation.
Since VPI got rid of the idler flywheel for later models, I've been toying around and did that, too..
So what happened? Did the world fall apart?
Honestly, I can't tell the difference. And without the idler flywheel, the whole turntable "package" makes a much smaller footprint. With and without the idler flywheel, I've been using the odd but yes-it-works-great piece of dental floss to drive the turntable platter. And the VPI SDS speed controller in both cases (the only way to get 45 RPM), so the only A/B difference is eliminating the flywheel idler.
The base it sits on is very heavy and damped, and it's using the stock VPI spring-loaded isolation/leveling feet which supposedly aren't the cat's meow but seem to work fine for me. The stock 12.5 tonearm with a Shelter 90X cart.
Anyone's thoughts? Has anyone else tried just simplifying the drive that way? It certainly looks more steampunk with the extra belt and idler gizmo, but simplicity is appealing. What intrigues me is this is essentially what VPI did in later models.