[Listening Test] 40 mm Platter TPA for Michell Orbe and Gyrodec

Product: Machined acrylic 40mm platter for Michell Gyro/Orbe
Manufacturer: True Point Audio Ltd. - UK
Contact: Charles Melling info@truepointaudio.com (+44)78 40 377 019
Prices: TPA 40mm acrylic platter £670
Author: Mark Wheeler- TNT-Audio UK
Reviewed: Autumn 2024 to Spring 2025
Published: May 2025

Introduction: Tuning a Gyrodec

A popular upgrade path for Gyrodec owners is to replace the platter, usually with an Orbe platter/clamp kit. Such a seemingly Stage I hybrid is popularly known as a “Gorbe”. Your Old Scribe has heard almost every permutation and combination of Gyrodec and Orbe parts and would suggest that the Orbe platter should be a Stage III modification of a Michell Gyrodec. Within the Michell parts bins, Stage I should always be the bigger power supply for whichever motor you own. A Gyropower QC with an AC motor is a similar upgrade to the dc Orbetroller or Never Connected supply for the dc motor. Such motor power supply Stage I tuning affects PraT, soundstage and resolution.

A good turntable shelf is essential, wall or floor standing, depending on your house construction. Add Pete's Pylons and Pete's Pads or Audio Origami SpikePods to make for full fat Stage II tuning. Stage II affects resolution of the finer nuances of performance and by lowering various forms of noise and interference, Stage II really opens a wider window on the musicians' performances. Within that Stage II of tuning we might add the two layer plinth or spider. It is less obviously audible but still worthwhile. It reduces mechanical feedback from both the motor and the turntable support shelf. On the other hand, the Orbe platter removes the Gyrodec USP, the spinning weights, for only 1/3 of the total Orbe upgrade potential. What if there were an alternative product that avoids the brooding Darth Vader all black Orbe aesthetic but confers some of the acoustic benefits?

TPA 40mm Acrylic Platter

What we have here is an alternative platter upgrade for Stage III that preserves more of the silver Gyrodec aesthetic than the heavy black Orbe platter. A Gorbe loses the glorious hypnotic spinning gold plated cylindrical platter weights for a modest increase in soundstage scale and bass weight. Your Old Scribe believes that the Gyrodec's aesthetics are one of its biggest attractions so something closer to the original appearance should be an attractive proposition. The True Point Audio 40mm acrylic platter kit is just such an attractive proposition.

Comparative Platter Masses

Aesthetics and Theory

Wow & Flutter measures similarly for the Orbe and TPA platters with two belts and the Pete's Pylons. In theory extra platter mass should improve Wow & Flutter through increased rotational inertia. It may be a limitation of the accuracy of the phone apps we tend to use nowadays. To measure dynamic Wow, I chose a bass heavy outer track and using the Decca London cartridge (lowest vertical compliance cartridge in the Old Scribe collection). Here the extra mass of the TPA 40mm platter does confer an advantage over the standard Gyrodec platter but the peripherally concentrated mass of the genuine Michell Orbe platter is a further advantage. Both these differences are in the hundredths of one percent difference which is unlikely to be explicitly audible.

Sound Quality

Mdou Moctar's Funeral for Justice landed on the True Point Audio acrylic platter first. A lovely clean sounding red pressing, this amazing slice of fusion features takamba and assouf styled prog and blues motifs described as variations on desert blues, or Tishoumaren. Do check it out. As a first ever play on a freshly modified turntable it was refreshing to hear coherent presentation of upbeat material funking its way from the Euterpe Project active loudspeakers to my ears.

Despite being aware that many folks are sceptical about PraT (and your Old Scribe will contemplate why in a future editorial), this album is ideal to demonstrate it copiously. The time domain (pitch and phase) is well preserved atop this platter despite the dynamic load from the heavy 12 inch Audio Origami PU7Ti and low compliance walnut bodied Decca London cartridge.

Initial impressions with more familiar material are that the 40mm TPA acrylic platter has a slightly upbeat quality compared with the Michell Orbe platter, a bit like the characteristic Linn pace. This is at the expense of some of the Orbe's noted bass weight. Of course the Pete's Pylons do help with the bass definition and pitch stability. Listening to Frank Zappa's Them or Us and Tinseltown Rebellion, this presentation really suited the Doo-wop tunes, reminding me why the Linn Sondek is such a popular choice among Zappistas.

While swapping platters back and forth, it was worth experimenting with clamp tension and knurled nut tension, out of curiosity. The Orbe clamp behaves exactly as it does with the Orbe platter with similar audible effects. There is no reliably observed difference between the knurled nut finger tight and very tight with a soft-faced wrench. Omitting the knurled nut entirely was also inaudible if removed after being finger tight. Omitting the knurled nut entirely and simply plonking the platter over the bearing resulted in an obvious loss of detail and bass clarity. There were no measured differences. So the knurled nut is essential on both platter types but its tightness is relatively unimportant.

Having just put my whole Zappa modest collection through a cleaning regime, 6 of my Zappa albums were played before moving onto the Georg Solti/LSO 1965 recording (1983 Decca Jubilee reissue) of Bartok's Concerto for Orchestra. Again, competent PraT is essential for Bartok's 1943 composition. Recorded 20 years after its wartime genesis, its vigour and complexity demands a different kind of resolution that eludes many systems more suited to small ensemble rock and jazz. No system can recover what has been missed by the front end and this recording is a different test of information retrieval. The well documented immense soundstage of the Michell Gyro/Orbe family is maintained by the TPA 40mm platter while resolving the finer details of a complicated orchestral performance.

The Reference Recordings RR-23 original instruments take of Vivaldi and Bach quartets directed by Albert Fuller is one of those go to audiophile clichées capable of making any system sound better. For a reviewer this simply means establishing where lies the extent of the envelope with any combination of equipment. Again, the TPA 40mm platter reveals as much information as the original Orbe platter, but presented in a leggera style. Sonically, fans of ponderous power chords, power ballads, and grandiose musicals may prefer Michell's Orbe platter while those more fleet of foot may prefer the True Point Audio alternative.

Conclusion

For silver Gyrodec owners the True Point Audio 40mm acrylic platter is a no brainer upgrade compared with the Orbe platter kit being both lower priced than the Orbe platter/bearing set and being a better visual match for silver subchasses. Your Old Scribe is of the opinion that the lovely Gyrodec/Gyro SE platter is the final step in the Gyro upgrade path. The bigger motor psu will offer more gains in pitch stability and bass definition than a heavier platter and is therefore Stage I. The dual layer chassis isolation will reveal more low level detail and along with isolation feet (Pete's Pads or AO SpikePods for the max) and Pete's Pylons for Stage II. Once Gyrodec owners have reached Stage III there is now a choice of platter upgrades.

Your Old Scribe ordered and paid for a TPA 60mm acrylic platter and was supplied with both a 40mm platter and 60mm platter for comparison. There will be a review of the 60mm platter some time in the future. Your Old Scribe has happily lived with the 40mm version all Winter to get to know it well, in direct comparison to the genuine Michell Orbe platter on the adjacent all black Pedersen Orbe. One of these platters will be returned to the manufacturer after the review. That the True Point Audio platter has only been out of use for brief comparison purposes speaks volumes for its musicality. There, your Old Scribe used the word “Musicality” and expects to receive letters.

DISCLAIMER. TNT-Audio is neither a shop, nor a HiFi company or a repair laboratory for HiFi components. We don't sell anything. It is a 100% independent magazine that neither accepts advertising from companies nor requires readers to register or pay for subscriptions. If you wish, you can support our independent reviews via a PayPal donation. After publication of reviews, the authors do not retain samples other than on long-term loan for further evaluation or comparison with later-received gear. Hence, all contents are written free of any “editorial” or “advertising” influence, and all reviews in this publication, positive or negative, reflect the independent opinions of their respective authors. TNT-Audio will publish all manufacturer responses, subject to the reviewer's right to reply in turn.

Michell Gyrodec platter mass	3.3-3.5 kg depending on vintage
Michell Orbe platter mass	4 kg - 60mm thick
TPA 40mm platter	3.985 kg - 40mm thick

Further Aftermarket Michell Modifications