trying to understand the Linn motor

I have an old Valhalla Linn and it may be time to change its motor.
The board has been serviced and all caps upgraded.
As far as I can tell, the board produces 85 volts at 50 Hz.
If I am wrong on this, please let me know.

However, the motor on the Linn (Premotec 9904 111 31813) is 
rated at 110 volts (with -15% +10% voltage tolerance according to its spec).
This indicates that the motor should not be driven with less than
93.5 volts (-15%).

So, what am I missing ?


Improved power supplies for AC Motors like the Linn Lingo and VPI SDS will typically provide start up voltage (in North America) around 110-115 volts necessary to start the motor and achieve rotation of the platter. 

Once that rotation is achieved they then reduce voltage provided to the motor as reducing the voltage also reduces noise and vibration in the motor itself, resulting in improved sound quality. 

I run my Gyrodec with original AC Papst motor manufactured in 1981 using a variac and dial the voltage down following startup to around 53-55 volts, which is just enough to keep the platter spinning.  

If you place your hand on the motor housing while doing this you can literally feel the vibration from the motor dropping away as you reduce the voltage and the benefits are audible.

There is nothing wrong with your Valhalla or motor. That is not to say that an improved motor might result in better sound quality; that is a possibility. But it is not "necessary" to replace your motor because of the specs mentioned.  
Valhalla boards need to be refreshed, they tend to eat themselves through thermal wear. Off or on. I kept my valhalla’d LP12 on a power bar switched power arrangement and only powered up the table with 120vac, when it was time to use the table. But I see you’ve refreshed the board. They can literally burn the boards out and traces right off. (long term thermal stressing)

Another option is the very decent Hercules board for finally having 33/45 on the same table and to keep the 50hz motor. (Used original Lingos suffer the same thermal fate and need to be rebuilt.)

Both the lingo,and the Valhalla have the two stage power thing going on...and I think the Hercules as well.

It is an easy swap. (the Hercules board)

Soft foam earplugs are good for plugging the bearing well when flipping the table over to do the board swap.
My situation is a bit weird....

I have an Ariston RD11 in the US.  Its Valhalla board has the 3.9Mhz crystal (for 60Hz).  However, at the output, it has the 0.22uF capacitor designed for the "110 V ac-50Hz: C=0.22mF, speed = 250 rpm" output.

I cannot figure out what the board is outputting.  Is it 50Hz or 60Hz ?

I need a scope to figure it out.

I need a 50Hz pulley for my US Ariston since moving to a hercules board requires the motor to be driven at 50 Hz.  I can always change the 45 rpm crystal on the hercules to a 3.9Mhz and make it work at 60 Hz but that is my last option.  This way, I could drive both 50Hz or 60Hz motors, but I prefer the pulley method first.

Linn likes to run the TT motor at lower voltages to reduce motor vibrations... The Lingo drops the voltage to 60V once it stabilise... The Valhalla is locked at 85V all the time.
I almost always give my platter a hand spin as I power it on to make it easier on the motor & the belt.  I guess as long as I continue doing that I can probably lower the voltage even more (like 60V as in Lingo).

I wonder what the lowest threshold voltage is for it to stop altogether.  I will make that experiment one day....

My memory is faulty on that re the two step voltage thing... as I lowered the voltage of the sine on my rebuilt Valhalla board and now sometimes assist the platter when it is spinning up.

Never bothered with the lingo yet, as....I'm waiting for the right auction/sales snipe moment.

Cheap ass, like many analog guys. So cheap (and dedicated) I got into the audio business, to get closer to the source point.