[rcag_ils]

I should leave it alone instead of mounting it.

[jimdgoulding]

Ain't no resonances with dat. 

[Letitroll98]

Swwweeeett!

[JCarney]

$39.50??!! Is that what it sold for new??  Ok, I'm jealous. Wicked cool find though.

Have fun with tat.

JCarney

[rcag_ils]

An indirect drive project under way.......

[rcag_ils]

The Indirect Drive motor bearing recieved a thorough cleaning, all varnish looking 50 year old oil is gone, then the bearing is filled/coated with Mobil-1 oil, the result is the amazingly fast pick-up speed, who says direct drive has the fastest pick up speed.

[rcag_ils]

Yes, the indirect drive motor mount, and the idler wheels mount both have brand new isolators (with the correct load strength) installed. The material for these isolators are designed for aerospace application.

[rcag_ils]

After nine hours of work on a Saturday keeping systems out in the field working smoothly, I came home and reassembled the motor module.

During the rebuilt, I tested the motor without the motor housing bolts on, thinking I might have to take the housing apart again. After I put the housing bolts back on the motor, I noticed the motor ran even better due to the correct seating of the rotor bearing.

Also, the motor isolators work great. When I was holding the motor mounting plate by hands with the motor running at full speed, I did not feel any vibration at all, very quiet and steady, I am sure it could be measured in a lab environment, but I had no time for that. It sure beats putting the motor right under the platter. Keep in mind these are the same isolators that were used on all the Empire turntables.

If you have an Empire turntable, and these isolators have never been replaced, it should be your first priorty to get them replaced, instead of worrying about other noise coming from other things.

That's it for now.

[rcag_ils]

Isolation, isolation, isolation. Noise isolation is the number one priority in any turntable. The idler wheels driven by the motor, then transfer the driving power to the platter, indirectly drive the platter, since they are made of rubber, therefore provide some form of noise (from the motor) isolation to the platter.

Also, the idler (indirect drive) wheel mounting plate is further isolated from the chassis via noise isolators to ensure minimal noise transfered from the motor through the chassis to the platter, also prevent airborne vibration from getting transfered to the platter as well. Keep in mind that the motor's already isolated from the chassis via four isolators. The original plinth that the system will be mounted on is also very massive. So it's sort of a triple isolation system. It still is not the perfect noise isolation system (there's no such system), but it's very effective.

Note: some isolators may look similar, or even look the same as these, but these have the correct load capability, isolators have different load rating. Using incorrectly rated isolators would defeat their purpose.

Both idler wheels measured just a hair below 2.5" with no flat spot, brass bushings have no play at all, therefore they are still acceptable for use. Of course, all moving parts have been lubbed with Mobil-1 oil to prevent wearing.

As you can see, throughout the history of turntable, designers worked very hard to isolate noise from getting onto the platter. Why are some manufacturers in the 70's, 80's, even today, purposely making the platter part of the rotor of an electric motor is beyond me. For durability? Ease of maintenance? Fast pick up? Speed stability (with a neon light shinning on the dots, more noise, they just love to generate noise, don't they?), More suitable for scratching DJ? Personally, I don't think it's a good trade off for good sound.

[ricmon]

This is one of the most interesting builds I've seen on the AC.  I cant wait to see the final results.

Ric

[rcag_ils]

Everything's moving right along. The main drive module is almost complete, with the exception of the wiring. I'll do the wiring last, since I still have to hunt for a noise bypass cap for the power switch. I just love the isolation system that's being used in this model; massive, heavy plinth, isolators for the drive motor, isolators for the idler wheels mounting module, rubber idler wheels for the heavy platter.

In comparison with the garden variety "direct drive" turntables of today, in order for the direct drive system to work OK, it's platter has to be lighter, which would be more prone to unwanted resonance. The platter on this one is not as heavy as my Ariston RD11, but more hefty than most modern "direct drive", to me, heavy enough.