Idler wheels and TT speed

[walyfd]

Ok, so I volunteered to rebuild a Garrard type a for a friend who's just getting into hifi and he basically refuses to follow protocol and have the idler wheel rebuilt. He insists he can somehow accurately grind it on a lathe and replace the lost rubber with an O ring.

He then insists the size of the wheel has no bearing on the speed of the turntable.

Who's nuts here, me or him?

[electra225]

My initial reaction is that your friend is being unreasonable, and is tying your hands for success.

[William]

I would agree with Greg, and, diameter does play a huge part in accurate speed. I'm not saying this just because, it comes from experience, experience that came from trying to make one of my RCA 45 players not sound like the Chipmunks singing when playing.

Bill

[back-2-mono]

All that work (Garrard pusher-platform models are a bear to overhaul) and the owner won't spring for a properly re-built idler?
Charge him more labor 'cause you risk a call-back on this one.

[walyfd]

I'm actually doing it for dinner at Keens and drinks in NYC...

[electra225]

I wish you well with the project.

[William]

I find it puzzling, if your friend can afford Keen's restaurant, why can't he spring for a new idler? I wish you all the luck with your rebuild.

Bill

[walyfd]

Think that's bad, my preferred bars are Bemelman's at the Carlyle, the Campbell Apartments at Grand Central and the Rainbow Room...

Don't worry. I'll break even...

[William]

I have heard of Bemelman's and of course the Rainbow room. How far are you from the City?

Bill

[TC Chris]

Back to the speed question. The idler diameter has nothing to do with turntable speed. The motor shaft/turret/output diameter does, but not the idler. The turntable's inside diameter does too. But not the idler, which just transfers motion from one critical diameter to another.

Chris Campbell

[walyfd]

I've also read what you posted on other boards, however, the Garrard is a torque hungry changer and that tire is critical for it all to work. It's like putting 225 tires on a car designed for 235s... it'll go but the speedometer will be off... also this lathing idea will introduce so many other issues like wow and flutter.

I'm 125 miles to midtown... talk is we might get train service back to NYC... Im not holding my breath.

[hermitcrab]

I don't believe the idler has no bearing on the final speed of the TT... the motor spins roughly at 3500 rpm , the idler is what reduces the speed to the platter ... so whether you use a 1 inch idler or a 2 inch makes no difference in the platter speed? I'd like to see that proven in a YT video...