SOTA Eclipse Roadrunner Tachometer for Platter Speed RPM of all Turntables


Free Lifetime Technical Assistance
SKU: Eclipse Roadrunner
Brand: SOTA


This beautiful little monster will let you know all of your
problems. If you think your table is perfect, this is the device that will
prove it. Install a magnet under your platter, and then the sensor to your
plinth and it’s time to know the truth. Is the speed varying over time? Do your
motor and platter keep tempo perfectly like a metronome? After installing the
Roadrunner by itself you may be convinced that the Condor and 3-phase motor is
also on your wish list to eliminate all of your problems. (Vinyl related, of
course. We can not be held responsible for your “other” problems.)

The RoadRunner is a microprocessor controlled digital
tachometer used for monitoring turntable platter speed to 3 decimal places of
resolution. The internal time base is a temperature compensated crystal
oscillator (TCXO) accurate to 2.5 PPM (±0.00025%) with less than 1.0 PPM aging
per year.

The tachometer uses a hall effect sensor and a small magnet
attached to the underside of the platter to sense the platter rotation.

Note: The magnet MUST pass within 1/8” of the sensor
to trigger properly. The closer the better (without making contact).

Note: The sensor PCB and magnet MUST be firmly
attached for proper operation.



Dimensions: 3.565″L x 2.50″W x

Weight: 4 oz.

Case: 1 piece Extruded Aluminium.

Operating Modes:

Standby, Sleep, Normal.

Power Requirements:

DC Supply 9VDC 100 mA nominal; 5mA Sleep


Display: 6 digit LED direct readout of platter speed
in RPM

Resolution: 0.001 RPM

Serial Data: 3.5mm connector 9600N81 DCE

Freq Stability: Crystal Controlled ±2.5PPM


Direct connection to Condor Power Supply Unit provides
digital synchronization of platter speed to ±0.005 RPM.


Attach the magnet to the underside of the platter near the
edge as shown below. Attach the sensor PCB to the plinth so the magnet passes
directly over the hall effect sensor (Q1) as shown. Connect the tachometer to
the sensor by plugging the 2.5mm jack into the back of the tachometer (marked “Sensor”)
and the 3.5mm right angle jack into the sensor PCB. Plug the wall adapter into
an AC socket and connect the other end to the tachometer (marked “9VDC”). Press
the On/Off button on the back panel; the display will show 5 dashes.

Verify operation of the sensor by manually rotating the
platter until the magnet is directly over the sensor. Whenever the magnet
triggers the sensor, the left most LED display will turn on the 6th dash.

Turn on the turntable motor to start the platter rotating.
The tachometer will display the RPM reading after 2 complete revolutions and
will update the display on every revolution after that.

When the platter stops rotating for more than 2 seconds, the
display will again show the 5 dashes. If there is no activity for 5 minutes,
the tachometer will go to sleep and blank the display; it will automatically
detect activity when the platter begins rotating again and exit sleep mode.

The On/Off switch can also be used to enter sleep mode by
pressing and holding the button until the display is blanked.

Operation with Condor Power Supply: The tachometer
can be connected directly to the PSU via a 3 wire serial cable in order to
synchronize the platter speed. Operation is completely automatic with no user
intervention needed. The tachometer outputs the speed reading once per
revolution. The PSU compares this reading to the speed on the display and can
make micro-fine adjustments to the output frequency to lock the turntable speed
to within ±0.005 RPM. The adjustment is done slowly and evenly over the entire
next revolution and is inaudible to the listener (in most cases, the adjustment
is <0.0005 RPM per step). The turntable remains on speed independent of the
belt tension, bearing oil viscosity, drag from the needle or any other
variables that cause the table to drift over time with speed.

Note: Whenever the PSU is applying a correction to
the speed, the decimal point will blink on the PSU’s LED display.

Accumulated Playing Time Counter: The RoadRunner
tachometer has a built-in accumulated playing time counter. The counter shows
the total time the platter has been spinning and can be used to determine when
the stylus needs to be re-tipped. The counter can be displayed and reset to
zero when the stylus is replaced.

To display the accumulated playing time,
disconnect power, press and hold the On/Off button on the rear panel while
inserting the power cable. The display will show the firmware version on the LED
display (must be v1.10 or higher). Release the button, press and release again
to advance to the accumulated time counter. The display will show the total
playing time in hours and tenths. To exit without changing the setting, press
and release the On/Off button. To reset the counter to zero, press and hold the
On/Off button until the display shows ‘Clr? n’. Press and release the On/Off button
to toggle between Y/N. To reset the counter to zero, press and hold the On/Off
button when the display shows ‘Y’.

Additional information

Weight 0.00000000 lbs


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