GB2310075A - Audio turntable - Google Patents

Abstract

An audio turntable is designed to allow both clockwise and anti-clockwise rotation of its platter via a manually operated switching device.

Description

AUDIO MIXING TURNTABLE This invention relates to an audio mixing turntable.

Almost all hi-fi systems comprise an audio turntable for playing vinyl records.

There is a special type of turntable designed for audio mixing and is widely used in recording studios, clubs and by disc jockeys. It incorporates a manual pitch control for the speed of rotation of the turntable platter.

These tumtables however, operate in a single mode only, where the platter of the turntable rotates clockwise. Moreover, this limits the disc jockey in his creative ability, having to manually spin the platter backwards (anti-clockwise) or employ the use of a sampler to achieve the desired sound effect.

According to the present invention there is provided an idea of controlling the direction of rotation of a turntable platter by means of a manually operated switching device. This switching device may be mounted directly on to the turntable casing, or how wed externally as a separate unit.

A specific embodiment of the invention anolied as a modification to the

existing maustry standard Technics/SL1200 NLK It or bLl;!lU MK II senes ot audio turntables will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows part of the printed circuit diagram for the Technics SL12ûû MK II or SL1210 MK II series of audio turntables.

Figure 2 shows both the truth table and circuit schematic necessary for connecting a suitable switching device and the connection points marked J1 thorough to J8 in Figure 1.

Figure 3 shows the exploded views of the cabinet and chassis parts of the TechnicslSL12ûû 1 200 MK II or SL1210 MK II series of audio turntables.

Referring to Figure 1, where marked, cut the existing circuit track to create an open circuit.

Referring to Figure 2, using a multiple way cable, connect a suitable switching device such as a 4 pole - 2 way switch to the connection points marked J1 through to J8 in Figure 1 in accordance with the circuit diagram shown.

Referring to Figure 3, drill a suitable hole in the upper half of the turntable cabinet to mount the switching device in the position marked P. Note that the cable must be fed through slot S as depicted.

Once re-assembled, the platter of the turntable will rotate clockwise when the switching device is in position A and anti-clockwise when the switching device is in position B, as shown in Figure 2.

Claims (6)

1. An audio turntable designed to allow both clockwise and anti-clockwise rotation of its platter.

2. An audio turntable as claimed in Claim 1, wherein the direction of rotation of the turntable platter is controlled via a manually operated switching device.

3. An audio turntable as claimed in Claim 1 or Claim 2, wherein the switching device is mounted directly on to the turntable casing (chassis) or housed in an external unit

4. A modification to any of the Technics'lSL1200 MK II or SLl210 MK II series of audio turntables to meet any of the claims as claimed in Claim 1 or Claim 2 or Claim 3.

5. A specific method of modification as claimed in Claim 4, wherein the electrical supply of any two drive coils in the motor are interchanged, whilst the supply of the third drive coil is kept fixed.

6. A specific method of modification as claimed in Claim 4 or Claim 5, wherein the electrical connection of the two position detectors in the motor, corresponding to the drive coils whose supply has been interchanged as stated in Claim 4, are interchanged, whilst the electrical connection of the third position detector is left unaltered.