Tri-Drive for  Pink Triangle Turntables

There are few inherent problems with the esteemed Pink Triangle turntable, but one of them is the axial play that can occur at the top of the bearing housing.

Although the mass of the turntable tends to centre the pivot ball of the bearing into the centre of the sapphire cup, there is a sideways pull from the drive belt pulling the platter towards the motor. This effect has a tendency to pull the pivot ball in the bearing to the edge of the sapphire cup.

To help correct this, we have re-positioned the motor onto the sub-chassis, inline between the platter spindle and the tonearm board, similar to the PT Anniversary thus producing a better balanced system. Also, If the platter is driven from three equal points about its circumference, then the balance of the platter is much improved. To achieve this, we have placed two pulleys and the motor pulley equally spaced at 120° about the circumference of the belt recess in the platter.

The result of all this, is an unbiased rotation that is true to the centre of the platter bearing and produces a much enhanced sound quality which is deemed by many as being the prime enhancement that is overlooked by turntable manufacturers.

Also, due to the platter now having a balanced drive, there is less 'judder' when the motor is switched on or when the speed is changed, so there is less likelihood of the belt jumping off the platter.

Fitting the drive belt is made much easier by using a split platter as shown below.

The Tri-Drive conversion can be used on the following Pink Triangle turntables: -

PT 1, PT Too, and PT Export.

The Split Platter

If you have a PT turntable, you will probably agree that one of the problems might well be 'fitting the drive belt'. This minor problem is made no easier with the PT Anniversary where you have to fit the belt around the additional pulleys. To make this problem disappear we have modified the acrylic platter so that it is constructed from two pieces as shown in the central photo below. This type of system is used by other turntable makers such as Funk, Linn and many others.

This modification also greatly reduces the risk of the sapphire bearing being damaged when changing the drive belt.

The smaller platter is easily assembled onto the turntable main bearing, and the drive belt fitted in place around it and the motor pulley. The larger part of the platter can then be placed on top of the smaller platter  to finish the assembly. Please contact us if you are interested in having your platter converted to a split platter.

Above are photos of the Split Platter which can be made by modifying your platter.
 

 

Comments from a PT enthusiast who bought the 'Option 3' kit, photos of his progress are shown after his comments.

Yes, I do think it sounds a lot better. I’m not in a position to do any measurements yet as my preamp developed a fault just after lockdown so will have to await its return....

I would say that there is probably a lower level of background noise, venue acoustics are clearer, the infamous “tunes in bass” are clearer. I think dynamics of music are probably handled more cleanly with less congestion in louder passages and layering of instruments- harmony clearer as a result.

So far listened a mixture of original and digitally re-mastered recordings. Mixture of classical/opera/ska/rock (well, Dire Straits), Ska and George Melly.

I might say the sound is perhaps more natural - dynamic.

My wife has a cherished (mono) recording of Walton’s facade which we are both enjoying (very important!).

Definitely worthwhile doing - just got to decide on new cartridge eventually! Mark W. Bristol.

       

 

 

The Tri-Drive Upgrade Conversion is available in 3 options : -

Option 1

This upgrade kit consists of : -

  • Tempate 1, this is to be used to mark out the hole positions for drilling in the for sub-chassis, so that it will accept the Tri-drive pulleys and the motor mounting.

  • Template 2, to be used to mark out the hole positions in the Top Plate.

  • Drive pulleys.

  • Tri-Drive pulley mounts, including screws and nuts and washers.

  • Motor mounting, including isolation spacers, screws, nuts, and washers.

  • Rear suspension mount assembly.

  • Larger Drive-belt.

  

Option 2 :

This upgrade kit consists of : -

  • Carbon fibre composite Sub-Chassis, pre-drilled to accept the motor mounting, pulley mounting and bearing assembly.

  • Tri-Drive pulleys.

  • Tri-Drive pulley mounts including screws and nuts and washers.

  • Motor mounting, including isolation spacers, screws, nuts, and washers.

  • Rear suspension mount assembly.

  • Larger Drive-belt.

Option 3 : -

This conversion upgrades your turntable to Anniversary standard, it is not a DIY kit, it is assembled and completed by True Point Audio from your donor PT turntable. It is considered by many to be the ultimate upgrade.

  • Your plinth is stripped and HDF segments are inserted, thereafter the interior is painted matt black.

  • New Carbon fibre composite Sub-Chassis, drilled to accept the motor mounting and pulley mounting and bearing assembly.

  • New carbon fibre composite armboard.

  • Tri-Drive pulleys.

  • Tri-Drive pulley mountings.

  • Rear suspension mounting.

  • New larger drive belt.

  • New acrylic Top Plate.

Please contact us if you require any further information on any of the above options.

 

Fitting the Tri-Drive Belt: -
Notes to be added later when we have some more photos.

Please contact us for price.

Copyright © True Point Audio Ltd