Products- Turntables

iota-audio-design  “small things that matter”

**** New developments ****

The Phase 3 iota QT turntables !

  • iota jot
  • iota QT
  • iota QT Ultra
  • iota QT Ultra SP

Our current 2016 range of turntable products represent our third phase of product development, they offer an ascending level of engineering complexity, cost, and of course performance.

Design details and principals.

Since the beginning of 1990's we have produced a number of turntable models bearing the name of QT. These have varied in design, materials, and the performance levels. The original QT designs were conventional in appearance, with hardwood plinths and solid top plate.

Around 1999/2000 the QT Evolution range was launched with a hardwood support frame, or with aircraft aluminium tensioned side rails, and removable arm plates, and granite base board.

The 2016 phase three range now available are very different in both appearance and materials from the original, but the design goals remain the same, we aim to provide the maximum musical enjoyment from vinyl records with an accurate and honest portrayal of what was actually recorded.

The turntables.

iota jot

The starting point for this product was the aim to develop a turntable that despite its diminutive stature must still to be capable of producing excellent performance.

The iota jot represents a distillation of all our basic design principles that we have adopted in our other phase three products, and still using the same modular design principles, simply a smaller package.

When we set out to build a turntable that sells at a lower cost we made a conscious decision not to simply build a turntable down to a price, as this would inevitably jeopardize the project and result in a compromised turntable using low cost materials. In fact we have not had to compromise on the materials used in any way; we have simply reduced the scale and size of the components, rather than using cheaper and therefore less capable materials and design techniques.

iota QT (Ph3)

This is much more than simply a scaled up  version of the iota jot, in fact it includes many of the design aspects of our top models.

The iota QT (Ph3) is a full size free standing turntable, with an L shaped structure; in standard form it is not supplied with a base board. To form the "L" shape of the turntable it uses large super ridged, extruded aluminium support rails of a similar design to that used in our other models.

iota QT ultra & SP (ph3)

These turntables have been developed over a number of years using design principles from other products both in our current and previous model ranges as a basis for this development. Consequently many of the materials and techniques have been further tuned and defined to produce these.

The iota QT ultra & SP (Ph3) are full size turntables that use large, super ridged, extruded aluminium support rails of a similar design to that used in other models, to form the “H shaped” structure of the turntable, in  standard form they are supplied  with a base board constructed from either 18mm cross lapped birch ply, with radius edges and corners, finished in a durable textured black finish, or diamond polished granite on the SP version. Three support feet are fitted to the base board for levelling and the metal chassis is resiliently mounted from the baseboards.

The iota QT ultra (Ph3) uses the multi laminated material platter or MLM, and the SP version has our multi component Spindle platter .

Chassis, motor, and main bearing of 2016 range

To achieve our basic design goals it is desirable that the chassis of a turntable be a stiff, strong, resilient structure that offers excellent control of resonance and ringing. We have chosen to use an anodised extruded aluminium structure, that is immensely strong and stable under all normal conditions.

The complex external shape of the extrusion, as well as its internal stiffening ribs, increases the rigidity of the beam rails that makes up the main chassis components of our current range. This provides a structure that has enormous strength and stiffness when compared to a solid material while at the same time offering a lower mass, thus reducing the storage and release of unwanted vibrations.

To house the motor & main bearing we have created a module for which we have used a high quality rugged, die cast aluminium alloy box, this offers an enclosure that is both exceptionally rigid and strong and it also provides for improved EMI/RFI shielding, and its material structure is extremely consistent in all other respects. The main bearing of the turntable is made from bronze, this is rigidly mounted into this module, and it is then heavily damped and braced with a number of different damping materials and compounds used. In a separate section of the module the high quality AC synchronous motor is resiliently mounted and enclosed by damping materials. The whole module is fitted to the chassis with decoupling gaskets and then mechanically fixed to the rear and front chassis beams to form the basic  shape of the turntable.

The arm board module is again a similar high quality die cast aluminium alloy enclosure, this is mechanically secured to form a cantilever to the rear chassis beam of the turntable. The aluminium extrusion beams that make up the turntable chassis have “T” slots and the fixing mounts that hold the arm board module are located within this “T slot”, this allows arms of different effective lengths to be easily accommodated by simply loosing the arm board mount and then sliding the whole assembly along the chassis rail to the desired position, thus achieving the correct tonearm geometry, and then simply locking the arm board in place.

The arm board module uses constrained layer damping principals, with several different damping and resonance control materials used that are bonded to its internal structure. When using tonearms without height adjustment, and in order to accommodate cartridges of different dimensions non resonant spacers of various different dimensions ( dependent upon the cartridge height) are available to be used between the arm board and its enclosure body.

The whole turntable is supported on height adjustable feet, these are made from a combination of natural cork and polymer resin damping composites, faced with anti slip material. This combination provides a stable support with excellent acoustic properties, and the turntable can be easily levelled if the surface upon which is to be used is not level.
The MLM Platter

During development of these latest Phase 3 turntable designs we experimented extensively with alternative platter designs and materials, one of the solutions we have implemented here is the MLM platter. This is a combination of an external shell of an extruded synthetic polymer that is very close to the material properties of vinyl, and on the circumference of the platter shell are bonded two resonance control damping bands, to further enhance resonance limitation the internal structural core is made up of different materials bonded in the form of multi laminated materials (MLM), hence the name MLM Platter.

The structural core provides the dimensional stability and mass, whilst the multiple layers of different materials are bonded in such a way that resonance from the main bearing and acoustic feedback are controlled. As a standard accessory we supply a natural cork mat as the final interface between vinyl and MLM platter, as we believe when combined with the MLM platter it will produce a neutral combination of damping characteristics, however as the mat is not fixed the final choice of the most suitable combination is open to user preferences. The addition of peripheral mass weights to the base of the MLM platter aids rotational stability, as it adds mass where it will make the greatest difference, rather than simply uniformly adding mass to the platter, however the weights are fixed to the platter in a well damped & decoupled manner.

The top of the main bearing and its spindle on our turntables is manufactured from gunmetal alloy, and we supply a record clamp to flatten the vinyl record onto the surface of the cork mat, this clamp grips the gunmetal spindle and does not damage the vinyl in any way.

 Single or laminated composite material platter?

Why have we chosen a composite laminated material for the MLM platter? When considering  the fundamentals of vibration control & comparing singular and laminated materials we would cite the following:

A speaker cabinet is subject to large amounts of vibration within the cabinet from the music produced, this can result in colouration of the sound we hear. In an attempt to reduce these cabinet colourations in the music reproduction, designers often resort to using thick cabinet walls or heavy damping to try to control or reduce these cabinet vibrations. If two cabinets of identical external dimensions and 18mm section are assessed, one of MDF/ particle board, and the other made from cross-lapped birch Ply, when the results for panel vibration are compared, the cabinet panel made from cross-lapped birch ply will outperform the MDF enclosure, so much so you would need to increase the section of the MDF from 18mm to 50mm to get the same degree of vibration control.

Why is this? The cross-lapped Birch ply is made with an uneven number of layers of thin Birch wood that are laminated using resin bonding, with each layer applied at 90 degrees to the next, and with no additional damping. Whilst MDF or Particle board, is a uniform and consistent board made from wood dust & powder that is produced by bonding the dust into a totally uniform panel under great pressure. When energy attempts to excite and vibrate each of these panels, in the case of the Birch Ply as each layer of the laminated panel is so dissimilar to the next in its material make up i.e. Birch layer / resin bonding / Birch layer at 90 degrees and so on, as to offer a shift in frequency transition at each different layer boundary through the panel. On the other hand the MDF is totally uniform in its material content and make up, as a result it will uniformly vibrate at a singular resonate frequency, therefore allowing more energy and vibrations to pass straight through the panel.

Selection of Platter material

Over the years numerous different materials have been used by countless different turntable manufactures for the production of the platter that supports the vinyl record. The platter on a turntable not only acts as a suitable flat and even support for the vinyl record itself, it also has the body and tip of the main bearing in the form of the centre spindle embedded in the middle of the platter. As a result even with the finest main bearings there must inevitably be vibrations as a result of rotation of the platter and bearing, and these must pass into the body of the platter and therefore into the vinyl itself in addition there is also the noise of motor breakthrough transmitted to the platter through the belt or simply the structure of the turntable.

There is also acoustic feed back from the musical noise produced from the speakers that is also acting upon the turntable. Therefore the cartridge which is by design a device to produce electrical signals as a result of vibration will reproduce all these extraneous signals in the form of low level noise. Therefore a platter material that could offer good damping, and is to a greater or lesser extent an “inert” material may therefore be considered desirable.

Another factor often used to select the substance from which a platter may be fabricated is the mass of the material. Dense heavy platters although initially slow to get to accurate speed may be pitch stable as a result of inertia once up to speed. Unfortunately high mass also produces more strain on the main bearing, and hence more noise when compared to lower mass materials, and once noise has been induced in a high mass material it is released for a longer duration.

Previous platter solutions.

Previously our turntables like many others used either acrylic or similar materials for the platters, with the aim that using a material that closely emulates the mechanical properties of vinyl itself would offer a close to neutral support to the record surface.

A platter made purely from vinyl is impractical for many reasons. Vinyl itself lacks structural integrity and therefore many designers try to achieve a close match to vinyl, whilst avoiding the limitations of vinyl itself, and acrylic is a very good compromise material for the purpose.

However when the platter is made from a singular and uniform material (like acrylic) its response when excited by vibration will be uniform, and this will occur specifically at the materials fundamental resonant frequency. Simply making a platter of a greater thickness, and therefore higher mass, but still from a single uniform material will not change that characteristic, only the amount of energy stored. As vibration can only be dissipated in the form of motion or heat, and acrylic no matter how great its dimensions will still therefore be subject to resonance and unwanted vibration.

In the case of a metal platter this will produce a “bell like” ringing mode, and any manufacturer using such a material must add some additional damping to try to avoid this. Rubber mats were often used in the past for this purpose. However the many detrimental affects on the vinyl record of rubber and similar materials were found to be undesirable. The same is true for felt mats, felt is also attracted and sticks to the vinyl record due to the static charge in many records, and felt is not particularly effective material for damping a ringing metal object like a metal platter.

External Turntable power supply

The illustrated QT power supply is based upon a design that has been available & in service for many years, the original commercially available versions of this power supply were sold at the beginning of 1997, the prototypes having been developed by us and used for some years before that (1992)!

The power supply was developed in response to the large number of major manufactures T/T power supplies that were proving to be unreliable. Therefore reliability was a major factor that we considered when developing this product. Not only did we want maximum performance but did not want to sacrifice reliability, and this has proved to be the case. We invested in good quality components and the results and longevity of the product speak for them selves.

The unit acts as a mains regenerator and affectively isolates the turntable from variations in mains frequency, and voltage. Frequency stability is now crystal locked to +/- 30 parts per million. In fact in order to provide both 33 and 45 RPM for this two-speed model we commissioned specific crystals, these were ground to our exact specification, as we found the standard commercially available items (often used by a number of other manufactures) do not actually provide true 45 RPM! Speed change is now of course achieved by the "flick" of a switch.

The sine wave to drive the motor is generated by direct digital synthesis, and the output is defined for both source impedance and voltage. The unit has been designed to offer excellent "headroom" with regard to the applied turntable motor load. The output from this unit offers five times the maximum load on a continuous basis. With more than eight times the maximum load available short term. This of course ensures that the power supply can be used with a large number of other suitable turntables on the market. The unit is also available for all other international mains supplies. None UK/ EEC voltages P.O.A.
iota QT Ultra

How is the Ultra specification different from  QT turntable?

The QT Ultra builds upon the same essential elements used in the Phase 3 iota QT, in that it is constructed from the same style of exceptionally strong anodised extruded aluminium sections, however rather than being configured simply as an open frame “L” shape it is formed as a closed and massively double braced “H” where each side of the main bearing and motor module are attached to cross rails, and a front rail is added to form the “H”, this front rail is then also further braced by die cast aluminium 90 degree corner braces.

In addition to these changes to the chassis, the arm board that is still cantilevered from the rear rail as before, but is also firmly braced and attached by dual supports to the front rail chassis members of the frame that form the “H”. Despite this additional bracing the arm board is still able to be adjusted in position to allow tonearms of different effective lengths to be accommodated.

The other significant difference is that the turntable is resiliently mounted upon a baseboard, that is in turn fitted with height adjustable feet of similar construction to the
other QT designs.

iota QT Ultra-SP

The Spindle Platter & more!

There are two different versions of the QT Ultra one uses a baseboard manufactured from high quality birch lap ply, and on this version is also the MLM platter. Whilst the SP version has a 10kg diamond polished granite baseboard as well as our Spindle Platter, and a number of other options, including upgraded PSU & bearing, and many custom finish options....

The Spindle Platter was developed as an alternative improved platter design, and as such is substituted for the MLM platter. The Spindle Platter is made up from 126 individual components,  including eight centrifugal high mass weights in polished 316 stainless steel fitted onto eight internally damped 12mm polished support arms. The mass weights are fitted with silicon rubber outer “O”rings.

The central hub sits on top of a mass loaded and damped sub platter. Manufactured in aircraft grade aluminium and stainless steel, this has the central 100mm filled with a combination of constrained layer damping materials and is faced with sealed cork. The centre spindle fitted to the main bearing is machined from 20mm  gunmetal. This platter and its extra long gunmetal spindle allows the user to experiment with a variety of different platter mats.

The Spindle Platter was developed to extend further our ideas of reducing the impact of platter colourisations & the negative affects on the playback of vinyl. This Spindle Platter and its  126 individual components include a combination of highly polished stainless steel (type 316) high mass peripheral weights, and aluminium alloy components as well as natural cork, Acetal turned components and advanced polymer resin bonding agents.

Our aim was to create a structure that offers high rotational mass, but to position the majority of the mass at its extreme outer edge, therefore to gain the maximum benefit of centrifugal force. In addition whilst the structure is designed so that it supports the vinyl record where it is most required, at its outer edge, but also at the centre around the turntable bearing spindle. The result is this configuration also helps to control any influence or noise from the turntable main bearing.

The addition of a effective clamp then holds the vinyl flat to this damped area at the centre of the Spindle Platter. However the area of the vinyl that contains the groove from which all the musical information is extracted will be devoid of any platter reflections or interactions. The interface mat is left to do its job, and nothing else, and again as its not fixed, alternatives can be exchanged to the preferences of the owner if desired.

The design uses the high mass peripheral weights mounted at the extreme end of turned and damped support spindles, each weight is effectively decoupled as much as possible from its support mount, and wrapped around the weights are damping rings that are the only outer edge contact with the natural cork interface mat. The position of the eight high mass weights allows the full positive affect of centrifugal force to be applied to the Spindle Platter; this helps to maintain rotational speed stability, whilst at the same time reducing to a minimum the deleterious effects that would have resulted had we simply applied mass uniformly to the whole platter. The eight separate weight/supports ensure the vinyl is not allowed to deflect at its edge whilst the central record label area has total support and damping applied to the gunmetal centre spindle, this is further enhanced by the use of a suitable record clamp.

The iota QT Ultra and the Spindle Platter were also part of our development programme to produce our own somewhat unique Satori tonearm. This uses bearing and support techniques as well as materials not previously applied or used in other tonearm designs, so we believe a new and fresh approach to a set of very old and familiar problems?