VOYD

A potted history of VOYD Turntables….

Having seen a prototype two motor belt drive turntable in 1984, Guy Sergeant and I thought that three motors in a 120 degree arrangement around the drive hub would logically be better as it was more symmetrical in terms of the belt wrap, dynamic speed consistency under signal load, suspension behaviour etc. In the following months, whilst still at Sheffield Polytechnic we built a proof of concept that was better than our existing Thorens and AR turntables even though it used somewhat noisy stepper motors. In the summer of 1985, having graduated, we built the first VOYD prototype using Papst motors, our own acrylic platter/bearing, sub-chassis, plinth designs etc. The philosophy was to use less mass through the design of the drive system which was enabled by the three high quality Papst external rotor motors. The platter was one piece acrylic to minimise energy reflection interfaces and the suspension based on simple extension springs as they did not have to provide any lateral compliance that single motor drive systems needed to tension the belt. This was demonstrated at the Penta HiFi show in the autumn of 1985 where we shared a room with the UK distributor of ProAc speakers and Magnum amplifiers whom we had met at the Music Room in Manchester when comparing the prototype with the Source turntable. At the time we used an Alphason HR100S tonearm and Goldbug Brier cartridge but these were not to stay for long….

At the show we met Peter Qvortrup from Audio Innovations. Our development environment quickly evolved as there was significant mutual interest, Peter could see the potential and we could see a ground breaking listening/development approach and ability to reach worldwide markets – we changed to Helius arms, Audio Note cartridges, Audio innovations amplifiers and Snell speakers and realised the capabilities of the three motor design with minor tweaks. I recall that when we got a pair of Snell J II speakers that Guy coined the phrase ‘sludge pumps’ with reference to the Gale 401’s we were using for development at the time! The Snells were so revealing….

We then committed to building the first ten turntables for sale as the start of the business, which then ran for some 11 years before handing over to Peter at Audio Note UK in 1996. After a couple of years Guy Sergeant moved to work for Peter and I carried on the business along with Nikki up until I joined HP Labs in 1996. Overall we produced in the region of 900 turntables……it is rewarding to see that some are still in use and sought after – we did have a perspective that if something is designed correctly, it should stand the test of time as opposed to having to come out with frequent updates….

Models

The VOYD

The original 3 motor turntable.

The first 10 had a ~150mm drive hub on the platter, some awkward levers to adjust the suspension (which we always changed out for the revised design when we came across them in later years!), a simple crystal oscillator 25/37.5Hz sinewave 16V single phase power supply with phase shift capacitors (47uF in series – 23.5uF) at each motor in the deck. The bearing was a relatively short PTFE sleeve conventional design and the sub-chassis made from separate anodised aluminium rails. The motors ran at half nominal speed – 750 rpm as this was deemed more appropriate in terms of potential vibration especially as there were 3. Also in order to limit heat dissipated in the motor at the lower drive frequency, the voltage was reduced, as specified by Papst, to 16Vac rms.

After the first 10, the drive hub was increased to 220mm, motors correspondingly moved outward, one piece sub-chassis, redesigned longer precision bearing with line bored bronze bushes, tapered/cone platter interface, redesigned suspension adjusters and larger power supply case with revised circuit design. Also the motors were fitted with a small thrust bearing to reduce end float.

The power supply was updated in early 1988 to actively drive both motor windings with a phase shifted sinewave in order to operate the motors closer to their ideal.

There was a final revision to the power supply where the size was reduced, recognisable by the black lid/base and red logo.

The Valdi

A 2 motor, pared back version of the 3 motor VOYD was developed in 1987 to provide a lower priced unit. 20mm thick platter (versus VOYD @ 25mm), simpler reamed brass bearing, U section chassis, split phase power supply built into rear of plinth (small external transformer), vacuum formed dust cover. Motors were run at 14V. Later on, the Valdi power supply was moved out into an external unit in the early 90’s, the same size at the VOYD with a green legend. This was driven by the fact the ST electronics M706B1 IC that divided a crystal by 2^16/17 to 50/25Hz became obsolete overnight. This was replaced by two 4000 series CMOS IC’s on a small daughter board mounted on the speed change switch.

We did produce a custom version for Audioplan in Germany – identical except for a square more ‘Teutonic’ plinth. 50 units

The VOYD Reference

Whilst based on the VOYD there were substantial upgrades and this was reflected in the price. Introduced in 1988. The plinth had a wooden inlay for the top plate and was piano lacquer finished (Mahogany, Black, White etc.) and a 12mm aluminium plate sandwiched underneath. The motors were Papst B282 – huge external rotor units driven by a large external power supply at 750rpm (25/37.5Hz 85V). These motors were discontinued after building about 20 units and we then sourced some slightly smaller B151’s but still substantial! The platter was polycarbonate (as opposed to acrylic) – much harder to machine as the stresses in the extruded raw material would cause significant distortion and the bearing was a tighter tolerance VOYD bearing. The suspension components were all braced/solid and the sub-chassis was a complex tapered, lightened design along with a one piece armboard for Helius arms. Overall just over 50 units were built.

The VOYD 0.5

This was a VOYD with a reference platter and bearing and motors running at 1500rpm and connected electrically in series as opposed all other units where they were parallel connected and 750rpm. The thinking behind this was that as magnetic flux is generated by current, connecting them in series forced each motor to generate the same flux. Also the higher speed resulted in a fourfold increase in stored inertia in the rotor but required a large brass motor damper to be fitted to absorb any potential small out of balance vibration. The power supply was similar to the large Reference but operating at 50/67Hz and 72V. Motor pulleys were small and had to be machined in situ on the shafts (requiring the shaft to be removed from the rotor) ~4.7mm dia compared to 9.45mm for 750rpm.

Upgrades

The polycarbonate platter and tighter tolerance bearing used on the reference was available as an upgrade to the VOYD 3 motor deck. Just adding this to a VOYD was an affordable upgrade but did not make the deck a 0.5 as can be seen above… I think this was dubbed a VOYD ‘Plus’.

Oddities

We did introduce a two belt approach – two pulley crowns were formed on the pulleys. It changed the sound – some aspects were better, some worse and so was a mixed bag.

Fitting the belt(s) under the one piece platter – I can’t deny this was awkward for some customers as it required a certain amount of dexterity!

The early single phase VOYD’s from 1985-1988 had 47uF/2 (23.5uF bipolar) phase shift capacitors (plus another series pair to damp the inductive switch off spike). In hindsight whilst the operating voltage was correctly adjusted down for the lower frequency, we did not alter the phase shift capacitor (as has been pointed out on the Steve Hoffman VOYD forum). In hindsight this does seem to be an error, albeit rectified and improved upon when the split phase supplies superseded from early 1988 on. I would add that torque was not a primary focus with the 3 motor, external rotor, configuration – the stored inertia was the focus as dynamic torque demand would require ‘slip’ which would then mean there was a potential for detectible slowing…. I will add a test in the motor section to provide some insights before confirming if there should be a retrofit.

Other Info

Belt size for all 220mm hub platters – 195dia, 5wide, 0.6mm thick Possible substitution 201dia 6wide 0.6mm thick. Clearly the 0.6mm thickness must be adhered to for speed accuracy.

Schematics – will post more when I get time…

Voyd + Later Valdi with full external PSU

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