Henry Engineering Turntable Controller MK.II User Manual
Henry Engineering Audio
503 Key Vista Drive
Sierra Madre, CA 91024
The Universal Turntable Controller is a remote control interface for use with professional direct-drive turntables.
The "UTC" converts the 'single button' start-stop control logic of the turntable to independent Start and Stop circuits,
so that separate START and STOP control switches can be used to operate the turntable. Either momentary or
maintained switches can be used. The UTC also provides outputs to drive RUN and STOP mode indicators, plus a
'logic' output for interface with auxiliary equipment. When the Universal Turntable Controller is installed, the
turntable's own start-stop switch is still useable for cueing records; the UTC will always stay "in sync" with the
turntable. The UTC is a solid-state device using CMOS circuitry for excellent RF immunity. It is designed to be
used with Technics* models SL1200MKII, SP25, SP15, SP10MKII and SP10MK2A turntables.
CAUTION AND DISCLAIMER
Installation of the Universal Turntable Controller may require a slight modification of the turntable. This
modification, though minor, does require the turntable to be disassembled so that connecting wires can be added.
DO NOT attempt to install the UTC unless you are a qualified technician. If you do not fully understand the
installation procedure, you are not qualified to install the unit! Disclaimer: Installation and use of the Universal
Turntable Controller is solely at the users risk. The UTC may be considered to be a 'modification' of the turntable
and may void any warranty thereof. The user is advised that the turntable manufacturer may refuse to service or
repair any turntable that has or has had a UTC connected to it. It is suggested that, should the turntable ever
require service after a UTC has been installed, the UTC wiring be removed and the turntable restored to its original
condition before it is sent in for service.
Connections to the UTC are made via the two "D"-type connectors on the unit; one connector is provided for each
turntable and its associated control circuitry. Mating connectors are supplied with the unit. Three wires from the
UTC are connected to the turntable: STATUS, CONTROL, and GROUND. A three-circuit 'miniplug' and jack are
provided for this; the jack can be mounted to the turntable chassis. The remaining wires connect to Start and Stop
switches and mode indicators. See Figure 1. Connections to the turntable are slightly different for each turntable
type. Refer to the section below appropriate for your model.
CONNECTION TO SL1200MKII AND SP25 TURNTABLES: The SL1200MKII and SP25 turntables are electrically
identical. It is not necessary to remove the turntable from the base; all circuitry can be accessed by removing the
platter from the drive motor shaft, then removing the cover beneath the platter. Mount the three-circuit minijack to
the metal plate where the AC power enters the turntable. Carefully drill a 1/4" hole and mount the jack using the
nut supplied. Be sure no metal filings drop into the turntable circuitry! Connect three wires to the jack; each will be
connected within the turntable. The sleeve of the jack is connected to the turntable GROUND. The tip will be
connected to the BRAKE POTENTIOMETER (R-201), and the ring will be connected to the turntables START-
Near the front-left corner of the turntable, locate a bundle of wires leading from the start-stop and speed selector
switches. Within the bundle, there is a yellow wire. This yellow wire is GROUND. Verify that the yellow wire is
ground by checking continuity to a known power supply ground point. Carefully remove some of its insulation and
tap onto this wire with the lead connected to the minijack SLEEVE. Also within the bundle is an orange wire, which
is connected to the start-stop switch of the turntable. Verify this by checking continuity between the orange and
yellow wires. There should be zero ohms when the start-stop switch is pushed. Carefully remove some of the
insulation, and tap the orange wire with the lead connected to the RING of the minijack.
Now locate the 'BRAKE'adjustment potentiometer, a small trimpot designated R-201 located on the right side of the
PC board. The wire from the TIP of the minijack should be connected to the CCW terminal of the pot. This is the
terminal closest to the turntable motor. Important: Set the trimpot to its FULL CCW position. Reassemble the
*Technics is a registered trademark of Panasonic Corporation.