Garrard 301 motor and rumble

But there is no way around the noise produces by the idler drive. You can lower it for a time perhaps but it will be back with a vengeance.

@mijostyn My phono section cuts off at 2Hz; the mechanical resonance of the tonearm/cartridge combo describes the LF bandwidth limit. I don’t see my woofers moving except for bass notes. I don’t do anything in particular to flatten my LPs.

Its not hard to keep an idler drive system working with low rumble. Once a year, make sure the platter bearing is clean and properly lubricated. Do the same for the motor and idler bearing. Clean the idler surface at the same time and you’re good to go.

An idler will get noisy because it can perish and get hard (and so go out of round) or the motor is allowed to grind against it while the platter isn’t moving. So its always a good idea to give the platter a spin before starting it.

Cheap idler drive machines often have more noise because the platter is able to resonate. A more massive platter, espicially one that has been damped, will be quieter.

One of the reasons our Atma-Sphere 208 was so quiet was because we damped the platter. Not only did that help the bass out, you could twock the platter with your index finger while a record was playing and not hear it in the speakers. One of the reasons the Technics SL1200 works so well is Technics bothered to damp the platter. Anyone with a turntable can take this as a clue.

The Empire 208 platter, which we used in the Atma-Sphere 208, was particularly well suited to a damping treatment. Idler drive machines might be tricky in that regard, but often if there is the will there is a way.

@mijostyn The Pabst motor used by Empire is one of the best synchronous motors I've seen for a turntable. That motor was used in one of the Rek-O-Kut turntables and its probably the only one to mess with. Rek-O-Kuts had a pretty massive platter though but can't be damped easily due to the idler drive. Most of them I've seen don't use the Pabst motor and seemed to need some time to warm up before they would play on speed. I've not sorted out why but its something to do with the motor. 

The older motors had to rely on the AC lines frequency which is held within limits but is not as stable as an electronically applied signal which can be changed to adjust speed.

As you can imagine, this really isn't true anymore- there are devices which feed a very frequency stable 60Hz output for older motors like that- people are doing that for the Empire machines. But the AC line frequency has been traditionally very stable regardless- I'm not sure on the Empire if going electronic wins anything. 

To Ralph Karsten; this person absolutely misunderstood your point about powerful motors eliminating stylus drag-induced speed variation and yet you refrained from correcting him.

@fsonicsmith I missed his comment.

FWIW, We stopped making our model 208 when Technics came out with the entirely revamped SL1200. I regard it as a better machine and have one in my home system. With a different platter pad...

@mijostyn

The old idler wheel turntables are less speed stable than any high end belt drive table primarily because of the older motors.

I don’t think this statement is accurate. The synchronous motors on some of the vintage machines are excellent as long as the AC mains frequency is stable. If the machine is properly serviced out, there isn’t any stretch between the drive and the load. So they should be more speed stable (and in practice this is borne out), but a lot depends also on the platter mass. The Empire machines got their speed stability from both the motor and the platter being very effective flywheels. Only a few of the idler drive machines had platters of that kind of mass.

I think the main reason you don’t see idler drive machines in production now is the cost of making the idler and speed change mechanism (since they are not made in large quantities). They require more service to keep them running properly. Its a lot easier to engineer a belt drive with only two moving parts which is also easier to fix since most of the time its just a belt replacement, plus anyone who wishes to be a turntable manufacturer has to compete with Technics, whose direct drive system is competent, reliable, well-priced and overall excellent.

One key to really good LP playback is a robust drive in the turntable. That is why the Garrard has a following, along with the Lenco, Empire and Technics.

No matter how speed stable with no LP, a wimpy drive will have speed variation when you set the needle down and could have more when there is heavy modulation since the drag on the arm is increased.

When there is a slight speed variation, IME you hear it as a slight shimmer in the soundstage. I suspect this is because the variation is so slight that you dont hear it as pitch, rather you hear the tonearm tracking force on the groove walls change as the arm oscillates slightly left to right as the skating force changes with the speed.

If this Garrard were my machine, I’d grease the main platter bearing, make sure the motor has a good lubricant (automatic transmission fluid works well) and finally has a good idler, whose bearing also has a touch of light grease.

You can get idlers rebuilt by Russell Industries on the east coast. They do an excellent job. Most of the rumble you get is from the idler, so the more precision you can get out of it the lower the rumble. Its also worth it to make sure the inside of the platter where the idler bears against it is clean, since any dirt/buildup there can add to rumble too.

If the idler has a sloppy fit on its axle, all bets are off. But IME that’s pretty rare.