Origin Live Building a turntable almost from scratch - Manual (Page 20)

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minus 2% are quite common on decks and the dc kit is capable of plus or minus 0.3% - the advanced dc kit measures
0.1% accuracy..
Please note the following points when setting the speed. Firstly all the figures below are based on setting the speed on the
deck using the centre track and letting the deck play for a good 5 minutes beforehand with the stylus on the record so
that the whole system has settled down. The regulators seem to take about 5 minutes to warm up, so speed is about
2mins 58 seconds for 100 revolutions when the system starts from cold. In other words it is 2/180 x 100 = 1 % fast
when started from cold. Speed variation with the dc kit varies minutely depending on the track played and cut of record.
Usually outer tracks play 0.26% slow and inner tracks play 0.26 % fast. When the speed at the centre track is set using
the strobe and then timed, the drift is usually 1 second in 100 turns from the rpms timed on the 1st track to the rpms
timed on the last track. i.e outer track measures 2min 59.5 seconds for 100 turns and inner track is 3min 0.5 seconds for
100 turns. This means a plus or minus 0.26 % speed variation.
Click the rotary switch to the 2nd click clockwise and set P2 so that the platter rotates at 45rpm using the above method.
The dc motors may be slightly noisy to begin with and are never completely silent as a/c motors are - This is thought to
be because they rely on a different type of precious metal brush. Having said this they still sound a great deal better in
performance terms. To assist "running in" you can disconnect the brown wire from the rotary switch and remove the
belt. The motor then runs at full speed. Allow this for approx 5 hours. After the running in period, reconnect the
brown wire and the motor should be quieter than when it first ran
Like most turntable manufacturers we recommend that you leave the turntable running between changing records as this
reduces the belt wear that occurs with constant stopping and starting.
Notes
Do not use the power supply for anything other than the dc motor or the power supply will definitely be irreparably
damaged and so might the equipment it is connected to.
Always de-power the circuit when troubleshooting by removing the power supply plug from the wall socket. The
circuit will take around 8 hours to run in and sound it's best.
In the first 4 hours of use from starting up the motor, the speed tends to drift but then settles down permanently. To
burn in the regulator board components we recommend at least 4 hours of running the motor before you accurately set
the speed.
Set up & maintenance of turntable
Set up
Carry out a final check on the levelness of the platter with the turntable resting on the surface that is going to be it’s final
residence. It is best to use a spirit level for this purpose.
You can now move on to the section on “arm set up”.
Notes & Maintenance
Notes
The Platter works best without any type of mat (including the Ringmat) or record clamp.
Maintenance
The deck is not prone to going out of tune - we recommend that you check the level of the platter after the first few days
as the springs initially need to “bed in” and every year or so after this.
Depending on your use of the deck, the belt should ideally be replaced every 2 years or so.
If you withdraw the sub-platter spindle you should put in a drop of oil to compensate for any possible loss.
Wow on the speed – can be caused by 4 main factors as listed below. Most of these relate to the freedom of rotation of
the sub-platter. A useful check is to see how freely the sub-platter “glides” round at slow speed with only the gentlest of
nudges.
Insufficient belt tension
Sub-platter “bottoming” on the top of the bearing house – check that there is a space of over 1mm or over so between
the top of the bearing house and the underside of the sub-platter
The brass insert at the bottom of the bearing house has somehow got lost – this is very rare but it is just possible – the
bottom of the bearing house should be flat due to the presence of an insert sitting in the bottom – you can feel this with
a long thin screwdriver or use a torch – if the surface is coned as you would expect in a drill hole then the insert is
missing and you should request a new one.