Michell DC motor type

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
I also want to know. I have one, the speed is unstable, got jitter when listening music. No idea what I can do to improve it, replace a new motor? My table is only 1 month old. I guess it's a design flaw in there tables, the power supply is only a 317, really a joke for a $2000 table...
 
Failure of the motor itself is improbable. It is, however, mounted in a rubber 'sock', the spindle protruding through a tiny hand-made hole in the rubber.

Now, if the sock shifts a bit, or if fragments of rubber get dislodged from the hole, parts can touch the spindle, giving rise to excessive noise and/or wow.

Another possibility is the stiff drive belt that has been offered as an upgrade during a short period. In my experience that belt is so stiff that just a couple of days of not using it makes the pulley make a permanent kink in the belt, leading to drive problems later on.
The stiff belt might be an upgrade, but only for those of us playing records every day and night.
It seems that Michell now deliver the old-style soft belt again.

There is nothing wrong with using LM317s in turntable DC motors.
 
I don't have a schematic, but I remember it's just wired as standard regulator.
There is nothing wrong to use 317, but the problem is 317 offer stable voltage only, but no way will maintain stable speed, this is a problem. I can hear jitter easily, especially for solo piano music. I don't know what I can do to improve it.
 
lovemov said:
I don't have a schematic, but I remember it's just wired as standard regulator.
There is nothing wrong to use 317, but the problem is 317 offer stable voltage only, but no way will maintain stable speed, this is a problem. I can hear jitter easily, especially for solo piano music. I don't know what I can do to improve it.


There was an application note (from AD maybe?) that suggested a circuit that inserted the motor resistance in the feedback loop I think, mm, I can't remember anything else, maybe some searching...
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.