In article , Roger Thorpe
wrote:
William Sommerwerck wrote:
Many turntables have a line resistor. It "does something" (that I
don't understand) to improve speed stability. Or torque. Or something.
It's not to reduce the line voltage.


It's a while since I looked, and I could be wrong but: The Rega planar
motor is a pair of multi pole two phase synchronous pancake motors
sandwiched together with the poles interleaved. The resistor and
capacitor are there to change the phase (lag or lead?) of one motor so
that the assemlby turns in the right direction when it is started.

That chimes with my understanding, based purely on having had to 'fix' a
similar problem with a friend's Rega a few years ago. Haven't commented
previously as I don't know the full details. I just replaced the burnt out
resistor with one rated at a higher power. And have since forgotten the
value.

Must admit I was less than impressed with the circuit at the time. From
this thread it does look like this resistor is prone to burning. Although
perhaps that is made worse by the risk of the motor being stalled or
loaded.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html