Maybe from www.centurysprings.com.au

(A guy on another forum uses part no S-952 under his turntable, although these ones are much more heavy duty than you require).

However there appears to be a few places in NZ that sell compression springs.
e,g www.natspring.co.nz/gallery/
www.nzspringworks.co.nz/compression-springs-nz

And some selling the conical shaped ones too eg www.kingcat.co.nz/products/13060. For seats?

To keep the purists happy and retain Daves original design concept I have sourced some coil springs to be added to the suspension system.

These are maybe 50% softer than the one and only spring supplied with the turntable originally. One is added to each corner near the sorbothane pad with two in the rh rear corner with the heavy arm pillar.

I get the impression that Dave's original concept spread the suspension load fairly evenly between the collection of springs and rather soft sorbothane pads.

The way I have configured this suspension system ( due largely to the chosen sorbothane hemispheres being higher rating at 70D  ie stiffer ) has the pads supporting maybe 90% of the weight with the springs only 10%.

I feel the sorbothane provides a much more stable platform while still having enough give to act as vibration absorption. Coil springs in compression are very unstable offering very little lateral support particularly in this application with the centre of gravity being at least 75mm above them.

I don't think Dave would be unhappy with this slight modification or tweak of his brilliant design.

If a heavier arm is added at some stage in the future additional coil springs can be added in the rh rear corner to compensate.

Nearing completion now, just waiting for Cambrian Plastics to manufacture a lid for the motor pod and a longer armboard in case Paul cant resist installing his 12 inch Wand. !!

Cheers

From what I gather and all the variations in Aura designs, I'm sure Dave would be happy with any modifications to his original concept, if it offers better sound quality.

In correspondence with someone who knew Dave
"As you're probably aware through Owen, after the Whittakers returned to Auckland & built their house in Albany after some years in Australia, finances were extremely tight & subsequent development of the Aura was a mixed bag, mostly constrained by cost.

The most significant development was of course the intermediate flywheel, although I feel something of a band-aid as accurate drive always plagued the Aura, presumably stemming from the repurposed VCR motors & control circuit employed. Experiments with tape drive were also a mixture of cost-cutting (the round belts are / were Michell = expensive) & a further attempt to improve drive. The suspension was always Mickey Mouse in my opinion, & I think your own efforts to tame the bouncy castle are definitely a step in the right direction. I feel if Dave had lived on & had the resources to develop the turntable further, a more sophisticated motor / controller & a properly damped, rigid base would surely have followed.

The salient features of the turntable & its real claim to greatness lie with the stabilised unipivot bearing & the massive platter & flywheel. Those serious core components - aided by their modular construction - are crying out to be mated with a better drive & chassis, & considering the Aura was always a work in progress with no two the same, I think Dave would certainly approve of any such developments."

Hi Cliff. Interesting assessment of the Aura turntable.

I agree that the platter bearing and flyweight set up is the design strength and that the chosen motor and suspension system is not so great.

However the addition of the outboard flywheel IMO sorts out any motor vibration and on this turntable anyway the rpm is rock steady.

If it's a 'band aid' its a very good one.

The description of the suspension as 'Mickey Mouse' and a 'bouncy castle' is a bit harsh but is an area that can be further refined.

Eliminating the suspension all together is one option, as you have done on yours, but I feel the set up we have employed on Paul's has resulted in an excellent compromise between isolation and stability.

The sorbothane pads have enough give to still provide a degree of movement while holding everything in place. I guess we could describe it as semi- suspended.

I'm sure Dave would approve.

The 'intermediate flywheel' idea may have been conceived partially for additional isolation for the motor, but as the it developed, it became evident to Dave that other significant benefits could be had. The concept was just another evolvement from Dave's endless experimenting.

Anyone who knew Dave at the time (c. early 2000s) will recall that Dave had at the time an Aura with twin motors (see below, possibly inspired by TTs like the Voyds) - obviously not cost-cutting.

By that time also, they had already been residing in their completed new house in Albany, Auckland for some years (from around 1999).
(They were in Brisbane for only a couple of years, c.1990-92.)

The heavy auxiliary/Interm. Flywheel development, was something that had already appeared in TTs such as the VPI HRX - changing from brass to painted/plated steel however, WAS done for cost reduction reasons. (I think mine was the first & only Aura with a solid brass Large Interm Flywheel.)

Dave always found ways to pursue his hobby & audio developments, despite not having any paid employment since he lost his insurance job many years back.

Tape belts - are becessary to fully harness the benefits of the Intermediate Flywheel. In order to utilise the Interm. Flywheel to increase the 'angular momentum' of the platter, it needed to be rigidly coupled to the platter - ie. using a non-stretch belt. The sonic improvements of using such a coupling belt are obvious when heard.

Suspension - as said, the Sorbothane pucks/hemispheres/squash balls provided support for the mass of the TT & the springs were used to 'balance' the eccentric arm pillar weights. Vertical resonant freq. of this 'suspension' was probably way too high Hz & some sort of pneumatic air suspension would arguably have been better. Also, rotational stability (stiffness) was not ideal - but this is the achilles heel of pretty much all 'suspended' belt-drive TTs. (One reason why the non-suspended Rega TT sounds particularly good.)

DarkLantern blog - darklanternforowen.wordpress.com

Jan 29, 2020 21:06:36 GMT 12 Graham said:

When using the monofilament thread is it taking longer to get up to speed due to the thread slipping ?

If so I would have thought this negates the idea of coupling the platter to the outboard flywheel.

My understanding of the system Dave used was to have a flexible belt from motor to flywheel to absorb motor vibration, but a not flexible coupling from flywheel to platter using belts with little or no stretch such as Pyrathane or video tape.

Not arguing, just curious how it sounds better on your Aura.

With no helping hand, it takes 6 to 7 rotates to get to speed.

Changing armboards, or arms, or adding extra armboard pillars etc all changed the levelling.

And re-levelling via the sorbothane pucks, springs and footers was a right royal PITA, requiring MANY multiple painful re-adjustments. And then when apparently right, after a while, things would drift

Requiring more readjustments under the very heavy platter.

I am much happier with my current non-suspended setup!

with the advent of modern stand alone isolation systems, there's no need for turntables to have built in suspension.

especially springs, all they do is go BOING !

I've been experimenting with different combinations of springs and the sorbothane pucks that make up the 'suspension' of the Aura and have arrived at the combination that I feel works best for this particular turntable.

The sorbothane pucks are 50mm diameter hemispheres with a height of 25mm. They are rated at 70D which I'm sure is 'stiffer' than those originally used by Dave.

When the turntable is assembled the weight sitting on these pucks is 25kg in total which compresses them by 4mm each without the addition of any coil springs. In this configuration the turntable is quite stable but retains enough give to absorb vibration so I guess could be considered to be 'semi-suspended'.

The combined weight of the tonearm tower, armboard and tonearm are concentrated in the rh rear corner which naturally results in that corner being compressed lower by about 0.75mm. Fitting the one and only supplied spring at the rear next to the rh rear sorbothane puck helps to lift the rear and this combined with the  pull of the belts results in it being as near as dammit to being level. While the belt tension is not really that great it is concentrated 120mm above the top of the sorbothane pucks so due to leverage can have quite an effect on the attitude of the platter.

If at a later stage a heavier arm with a longer armboard is fitted this will have surprisingly little effect on the suspension as has been confirmed by highly scientific experimentation. Well actually I just plonked some additional heavy objects on the armboard !! A very slight adjustment of the motor pod position to increase the belt tension sorted it out. An additional spring could possibly be added at the rear but I don't think it really necessary.

To my way of thinking I feel this is an ideal set up for the suspension on this particular Aura as it eliminates any tendency to act as a 'bouncy castle' while providing enough support and vibration absorption.

All now good to go and ready for collection by it's impatient and eager owner.

Hi Michael and Cliff - I am sure you are right about the benefit of not using springs and moving to more modern methods, and I may well do that, but I set out for a "restoration" in the hope of restoring this Aura back to some semblance of its authentic and original state. I expect that if you are restoring old cars you might not use the latest tyres but look for something generationally fitting. So I'm not taking anything away from more modern solutions for the Aura's suspension (and it would be good to hear what people are now using), but wanting to have my cake and eat it - a restoration back to original as possible, and available for modern suspension as well. In that vein if anyone comes across an original record clamp going spare do please let me know

No such thing as an original Aura!
I keep telling you that no two Aura's are the same, unlike a classic car...

As an extreme example, I draw parallels to restoring an old villa. Do you restore to original - cold, dark and damp? Or put in insulation, a new kitchen, an indoor loo and laundry while keeping the character high ceilings, ceiling roses and Kauri floorboards?

Forget the period record clamp. Its useless and does nothing, soundwise or aesthetically.

Oh, and definitely forget the "authentic" platter mat in Graham's pics, no matter how "original" you want to be.

It robs the sound of any dynamics and rolls off the treble. But if you want to be authentic...go for it!

Did an experiment with video tape as a main drive belt.

I must say that it really is a bit crinkley, making a low level noise. And its very fiddly. Sound wise probably on par with the rubber belts I've been using.

So will stick with my ultra thin "invisible" thread, as its still the best so far!

There's quite a difference between mylar tape & the various rubber-type platter belts - in my experience.

Re. the platter mats, these are usually dependent on system & personal tastes, it seems.
I've used most of Dave's supplied mats (tissue-thin agricultural 'paper', 'drawer-liners'....) - whatever works for you.

DarkLantern blog - darklanternforowen.wordpress.com

Feb 4, 2020 12:26:25 GMT 12 paulsaints said:

 I expect that if you are restoring old cars you might not use the latest tyres but look for something generationally fitting.

actually in response to demand from the classic set you can buy brand new pireli p7, michelin xwx etc, that look like the originals but are made with modern compounds.

tyres only last abut 6 years so you really don't want '70s stock on your lambo countach or 911 turbo.

Feb 4, 2020 19:42:14 GMT 12 Owen Y said:

There's quite a difference between mylar tape & the various rubber-type platter belts - in my experience.

Re. the platter mats, these are usually dependent on system & personal tastes, it seems.
I've used most of Dave's supplied mats (tissue-thin agricultural 'paper', 'drawer-liners'....) - whatever works for you.

Not so much in my system, video tape cf rubber.

But with the polyester/nylon thread there was a noticeable increase in leading edge attack, more solid bass/less bloom. A definite improvement.

Yes, type of platter mat is a very personal thing, and I've found several that work well with the Aura.
Auditorium 23 Hommage mat
Boston Audio mat
Puresound Tenuto

paulsaints how are you finding the Aura a few weeks in?

Hi - Thanks for asking - it is home but not set up, so can't say. Just busy with work. Tried it out at Grahams last week when picking it up and very impressed. Got it home with no incidents. Looks even better in real life than in the photos. When it's up I will post a photo of it in situ - Kef LS50's, Prima Luna HP integrated and Dynavector P75 Mk3 - just to whet the appetite. All nice combo's of black / silver / bronze. I'll start with a Rega RB-300 and Denon DL-103 and go from there.

Come on Paul, the suspense is killing us

Right - here you go:

Its a beautiful thing

Looking good Paul.

I'm so glad to have been able to restore this masterpiece back to life and know how much it will be appreciated and enjoyed.

Dave would be very pleased to see it sitting there in 'pride of place'.

Cheers 

Any chance you can separate those speakers at least a few feet apart!? LOL:)

Graham how did you find the Aura compared to your TD125 or Oracle?

All things considered that was a very fast turn around getting it up and racing again. I bet youre very pleased...and you have every right to be so!

Feb 19, 2020 17:06:48 GMT 12 Citroen said:

Any chance you can separate those speakers at least a few feet apart!? LOL:)

Yep - waiting for someone to spot that. They are that way for "family reasons" ... But the actual sound has surprised me - not nearly as bad as might be expected, and in fact quite good. Tried out today with a good range of vinyl (J.S. Bach Julia Fischer Sonatas and Partitias, Paul Simon There Goes Rhymin’ Simon, The Lost Recordings Dave Brubeck Quartet Live at the Kurhaus 1967, Diana Krall wallflower) and I get the full range of good lows from Diana, decent rocky mids from Paul Simon and some beautiful clear highs from the Bach. So, yep a scary compromise, but it works better than it should. The pair of Mullard blackburn 12AU7 tubes in the preamp section of the PrimaLuna probably help quite a lot. Honestly, this TT has brought back the joy into playing vinyl. It is a keeper.

That really is the ultimate goal, joy in rekindling vinyl, no matter how mono your records now sound!

Feb 19, 2020 17:49:31 GMT 12 paulsaints said:

Feb 19, 2020 17:06:48 GMT 12 Citroen said:

Any chance you can separate those speakers at least a few feet apart!? LOL:)

Yep - waiting for someone to spot that. They are that way for "family reasons" ...

No problem, if they are KEF Wireless models, you might use the KEF Control app to still throw a huge soundstage & optimise sound balance, for a sub-optimal placement like that

DarkLantern blog - darklanternforowen.wordpress.com

Damn, found a tweak I think might just well be permanent.
Early days but signs are encouraging so far.

Increased clarity, due to more taunt bass?, more dynamic sounding, just a sense of easier to listen to. Downside so far is a perceived slight lessening of fullness/meat on the bones.

Washing machine anti-vibration pads. They look to be made of any old common man made rubbery/plastic compound.
I've put them where the sorbathane pads and springs would normally sit.

Instead of hard cones?

DarkLantern blog - darklanternforowen.wordpress.com

Instead of polycrystals, which I found far better than the original sorbothane pucks and springs.

www.listeningpost.co.nz/Products/Archives-Discontinued/Polycrystal-Iso-3-Reference-Isolation-Feet-__I.17969__C.50400__N.27756