RoadRunnerDigital TurnTable Tachometer

Measures platter rotational speed to 0.001 RPM resolution

Contactless sensor using Hall Effect IC

RPM range: 28 to 99.999 RPM

First Reading within 2 revolutions

Serial output for PC logging or connection to Falcon PSU

Accumlated Playtime recorder for logging stylus wear.

Direct connection to Falcon Digital Power Supply Unit

Small Size: 3.5”L x 2.5”W x 1.2” H

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

The RoadRunner Tachometer provides a direct digital readout of the platter speed after only 2 revs and updates the display on eachrevolution afterwards. This provides a significant improvement over strobes and other devices (i.e. Sutherland Timeline) that are onlyindicators of fast/slow, not a measurement device. Strobes also lack resolution; often you need to track the “drift” of the marks overseveral minutes and compute the speed using a calculator. At 33 RPM, a speed error of 0.01 RPM represents a drift of 0.0063” perrevolution (about the thickness of this data sheet).

The tachometer uses a Hall Effect sensor and a small magnet attached to the underside of the platter to sense the platter rotation.The sensor requires approximately 0.25” (~6mm) of clearance to be installed properly. The magnet/sensor assembly can be installedunder the platter at the edge or under a sub-platter assembly if present.

The RoadRunner Tachometer can be connected directly to the Falcon digital Power Supply Unit via a 3 wire serial cable in orderto synchronize its output with the direct measurement of the platter speed. Operation is completely automatic with no user interventionneeded. The tachometer outputs the speed reading once per revolution. The PSU compares this reading to the speed on the displayand can make micro-fine adjustments to the output frequency to lock the turntable speed to within ±0.005 RPM. The adjustment isdone slowly and evenly over the entire next revolution and is inaudible to the listener (in most cases, the adjustment is <0.0005 RPMper step). The turntable remains on speed independent of the belt tension, bearing oil viscosity, drag from the needle or any othervariables that cause the table to drift over time.

Shown with optional Falcon Digital Power Supply Unit Sensor placement with magnet attached to the platter

Magnet