analog_sa said:
For a "traditional" idler drive yes, but build it just for 33.3 rpm and you dispence with a shed load of complicated and unnessesary work (modern power supplies can provide push button speed changes if needed).
I was having a play last night and lashed up a very quick set up useing an LP12 inner platter and a Airpax motor....no idler, just ran the motor on the sub platter and it got me thinking.....do we need the idler wheel if the motor can be moved instead?? The big problem would be what to use on the motor pulley. To soft and it would wear, affecting speed. To hard and it might not offer enough grip or decoupling, (would decoupling be nessesary if the motor ran smooth enough?)
Even if the above is to impractical, useing an idler wheel in a single speed set up should not prove to difficult me'thinks.
I have a Garrard 401 in a Loricraft type plinth and I love its sound, it is easily the best record player I have ever had (note; I am not saying its the best record player there is), the only thing I dont like about it is the huge size of the thing. I reckon I can make a single speed idler drive no bigger than a LP12.
I'm on a mission
idler wheels..
Idler wheels if using a rubber traction surface can offer some isolation or the motor/platter system. The larger the idler, the fewer the revolutions and theoretically tha potential for lower noise. Idlers need not be on the inside of the platter either, they can be on the outside. I am trying to develop a high precicion idler based on a Garrard Lab motor, Custom Bearing, and a custom idler. If I ever get it done I will post my findings.
It really need not be more complex than a belt drive. Adapter drive wheels for the motor can be machined and should not be difficult. (My donor Lab 80 was/is missing an idler, and either I have a new custom one built or hack something together myself).
Idler wheels if using a rubber traction surface can offer some isolation or the motor/platter system. The larger the idler, the fewer the revolutions and theoretically tha potential for lower noise. Idlers need not be on the inside of the platter either, they can be on the outside. I am trying to develop a high precicion idler based on a Garrard Lab motor, Custom Bearing, and a custom idler. If I ever get it done I will post my findings.
It really need not be more complex than a belt drive. Adapter drive wheels for the motor can be machined and should not be difficult. (My donor Lab 80 was/is missing an idler, and either I have a new custom one built or hack something together myself).
Re: idler wheels..
I have a spare Linn LP12 sub platter, so I am going to use that for starters. Think I will try it without an idler for starters, for the simple reason that I dont have one handy!
I dont know of any idler drive TT's that use a seperate platter and sub platter but I cant see any reason why it wont work.
Nanook said:
I have a spare Linn LP12 sub platter, so I am going to use that for starters. Think I will try it without an idler for starters, for the simple reason that I dont have one handy!
I dont know of any idler drive TT's that use a seperate platter and sub platter but I cant see any reason why it wont work.
The Weathers turntables dispensed with the idler by having a very soft rubber wheel on the motor shaft. The motor was free to pivot and set up so gravity forced the wheel against the platter. This, of course doesn't allow for much speed step down, so the motor was pretty slow speed (less motor noise was another benefit), but that meant that it didn't have much torque, so the platter had to be light. This meant a lighter bearing could be used, which was a cost benefit, and might be quieter also.
I believe it worked very well, but at the time (early sixties), most pickups had high enough tracking forces that they weren't really suitable for the table. The Weathers FM pickup had a low tracking force and so worked well, but at the time, people weren't into serious tables that didn't allow for choice of tonearm and cartridge, and the FM cartridge had to have a demodulator box, which probably was just too weird, so sales were limited, despite very good reviews.
But there is more choice of motors now, and plenty of cartridges that track at light weights, so the idea might be worth rescuccitating.
I believe it worked very well, but at the time (early sixties), most pickups had high enough tracking forces that they weren't really suitable for the table. The Weathers FM pickup had a low tracking force and so worked well, but at the time, people weren't into serious tables that didn't allow for choice of tonearm and cartridge, and the FM cartridge had to have a demodulator box, which probably was just too weird, so sales were limited, despite very good reviews.
But there is more choice of motors now, and plenty of cartridges that track at light weights, so the idea might be worth rescuccitating.
Nat Eddy said:
Thanks for that.....seems there is nothing new under the sun after all!! In fact, no need to make one, JUST BUY ONE!
Anyone any idea how to make the rubber pulley???
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