Project: Avenger Rim drive with BLDC motors & Class AB Amp

Re: New project: RIM drive with BLDC motors & Class ABamp

Postby Mr_Putty » Tue May 12, 2020 12:24 pm

Dorian
Thanks for the suggestion. I think I recall seeing the SOTA motor pulley had just one belt slot. Is that correct for a Prime upgrade or maybe that was for another table? I would definitely want more for testing.
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Re: New project: RIM drive with BLDC motors & Class ABamp

Postby vienna acoustics » Tue May 12, 2020 12:27 pm

Do not worry Mr. Putty I can send you Aluminum pulleys
I have fabricated many
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Re: New project: RIM drive with BLDC motors & Class ABamp

Postby Mr_Putty » Wed May 13, 2020 4:53 pm

vienna acoustics wrote:Do not worry Mr. Putty I can send you Aluminum pulleys
I have fabricated many

VA,
That would be awesome. Can you confirm the new pulley would be the correct diameter and fit on the SOTA motor upgrade? (I have yet to contact them)
Thanks for the efforts you are making,
JTA
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Re: New project: RIM drive with BLDC motors & Class ABamp

Postby vienna acoustics » Thu May 14, 2020 1:10 am

I will be in a position to advise you, if you will find out from SOTA the motor model they are using as well as the operational RPM and the Motor’s shaft size.

I know that they are using a different BLDC motor from Anaheim Automation but I am not sure which one. For my project the Anaheim Automation BLWR172S-24V-2000 Motors were used of which the shaft is 4mm. During operation they are completely noiseless.

In any case the pulley and belt shouldn’t worry you. I have read very positive feedback for their stock aluminum pulley and their flat belt. I also know that they have great experience with this modification and they will be able to support you
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Re: Project: Avenger Rim drive with BLDC motors & Class AB A

Postby vienna acoustics » Sun May 17, 2020 12:58 am

I have been listening to the BLDC Rim Drive with the Class D, three channels, amplifier for about a week now. During this period I am listening mostly, to familiar for me, albums.

The sound aspects which are completely and definitely improved are: the timing, the sound accuracy in all frequencies, the clarity, the details and dynamics.
I think that the smooth operation of the BLDC Motors, with no EMI, vibration and noise, has dramatically lowered the noise floor and this is the reason of experiencing the above improvements. The ambient and spatial sense are surprisingly improved too in a very high degree together with the sense of three dimensionality and palpability.

It is amazing how the increased noise floor was hiding so much sound information.

This extremely positive experience with the BLDC motors, made me investigate and read more about them.

They are a Hybrid type of motors which they behave like AC synchronous motors with the frequency determining the speed, when they will be fed with three signals with 120 deg phase shift between them.

At the specific project, Bill has designed the controller to provide absolute control over the frequency, amplitude and phase angles thus the motors are being controlled with extreme speed accuracy, stability, high torque, and no noise or vibration. As a result, besides the above mentioned improvements, the measured wow levels are really low. All the measurements (wow/flutter and vibration were cross checked with the Analog Magik, Test vinyls and software too)

The specific RIM drive is providing 33.33, 45 and 78 rpm and is maintaining the advantages of frequency determined speed.

Specifically the Anaheim BLWR and BLWS Motors are providing three times more torque than the Hurst motors. At start up, the BLDC rim drive starts with 5 rpm and speed is gradually increased to reach the 300 rpm. This eliminates the rim’ s fly wheel slippage over the platter.

The BLWR motors are incorporating precision sealed ball bearings at shaft’s both ends, this fact is providing zero , radial and axial, play during operation (thus no apparent vibration and noise). The sealed precision bearings need no lubrication and they are handling high radial loads like those which are witnessed with a RIM drive.
Hurst motors’ weakest point is the the fact that they are equipped with only one bearing at the shaft’s top end by leaving the rotor completely free to move uncontrolled at the other lower end. The bronze collar below the pulley is used to balance this uncontrolled motion but induces further noise.

With the drive not powered, when I am spinning the motors by hand I feel no cogging at all.

A friend of mine with a Prime Signature was so impressed with the improvement that ordered the Sota Total Eclipse Package and extra Anaheim BLWR Motors.

I can’t think of how someone who will listen to a BLDC motor once, will go back to Hurst motor. Also can’t understand how turntables of this level and cost are not equipped with such sophisticated motors and controllers from the manufacturer. the moment that the involved costs are not that much.

The benefits of the BLDC motors are recognized by many reputable turntables’ manufacturers and have adopted the use of BLDC motors, for example Dohmann, TW Acoustics, Sota is using Anaheim Motors, Kronos is using the Swiss made Maxon alike (I think) Acoustic Signature and Brinkmann, Kuzma is using Papst BLDC etc.

In my humble opinion, all VPI customers would be very surprised to experience what their turntables are capable to offer with a better drive. I am also sure that they would appreciate more and would definitely buy such a drive (With sophisticated controller, precision pulleys, improved belts and BLDC motor) which would offer them such a sound improvement, rather than a mere tachometer or a new expensive turntable with outdated motor and controller.

I will be listening to the BLDC Rim Drive with the class D amplifier for one more week before trying it with the Class AB.

P.S. With this post I don’t want to degrade or insult VPI in anyway. I own an Avenger Reference and I am loving it, I have auditioned many turntables and I could have gone easily for another, cost no object manufacturer. however during all the recent auditionings I was missing the sound and pace of my Avenger. This is the reason I have opted to spend on my current turntable rather than replacing it.
However I believe that such an important fundamental element, as the motor, is overlooked by VPI.

P.S. 2 I don’t know any turntable other than the VPI Avenger (and perhaps HRX with the magnetic drive platter and oil bath) that is providing such a platform for experiments. On this platform the user can easily test different thrusts, bearings, motors, transmission methods (belts or rim drive), Tonearms, shafts, lubricants etc

P.S. 3 another bigger, completely new Project is under consideration right now
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Re: Project: Avenger Rim drive with BLDC motors & Class AB A

Postby vienna acoustics » Tue May 19, 2020 12:08 am

I am copying here too my response to another thread, because I am realizing that besides the low noise, low vibration, speed accuracy and speed stability my current controller and BLDC Rim drive Is providing the right timing which I believe is the fundamental element responsible for my current amazing Listening experience.

QUOTE:
A sophisticated well designed speed controller besides the speed accuracy and stability, is providing the most important factor ....the timing.

Music from a turntable with the right timing is live, coherent and palpable. A turntable with the right timing will provide the right instruments sustains, articulation, more detail, musicality and resolution. With the right timing the spatial information and ambience of the live event is successfully transferred to the listener.

@J_Perkins, with his Upcoming upgrade will experience soon the accurate timing feeling and together with the low noise, low vibration BLWS motor will also experience the effortless flow of music.

The moment I had experienced the effect of accurate timing, I was amazed and I couldn’t believe the improvement degree of my turntable and the unbelievable improvement of the listening experience and feeling. Since then I have listened to many turntables but none that could replace my current Avenger Reference and what the Rim drive is providing.

UNQUOTE
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Re: Project: Avenger Rim drive with BLDC motors & Class AB A

Postby TravisBickle » Tue May 19, 2020 1:20 pm

Dear VA- Greetings and this sounds like quite the project. Have you and Bill discussed helping other owners of the current rim drive model make this upgrade?
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Re: Project: Avenger Rim drive with BLDC motors & Class AB A

Postby edw » Tue May 19, 2020 8:12 pm

Excellent! I may have to try the BLDC motor via the SOTA Eclipse package on my Prime.

VA, did you try the vibration measurement on AnalogMagik? It would be interesting to compare. I would assume the usual peak at 120Hz would be gone due to the BLDC.
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Re: Project: Avenger Rim drive with BLDC motors & Class AB A

Postby vienna acoustics » Wed May 20, 2020 4:06 am

Hi Edw,

the 120 Hz peak is common with single Hurst 300rpm syncronous motors. With the RIM drive where two Hurst motors were installed the measurements were different, with more peaks at different frequencies see the photo below. Later I will post the measurements results with the new BLDC motors.

B67785E3-0841-48CE-86F4-BF03530E56EB.jpeg
B67785E3-0841-48CE-86F4-BF03530E56EB.jpeg (1.18 MiB) Viewed 478 times


I had noticed that althought the original Hurst 115V 300RPM motors are marked with the desired value of capacitor (0.68MFd), the original VPI PCBs are equipped with capacitors of different value (0.47MFd). Perhaps this is done to reduce vibration but i undrestand that this also affects the motor at start up and the amount of torque it will develop.

capacitors.jpeg
capacitors.jpeg (2.02 MiB) Viewed 509 times
Last edited by vienna acoustics on Wed May 20, 2020 12:21 pm, edited 2 times in total.
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Re: Project: Avenger Rim drive with BLDC motors & Class AB A

Postby vienna acoustics » Wed May 20, 2020 12:06 pm

And the measurements with the Rim drive with the BLDC motors

7FBAAE34-A225-4159-95FE-77C6586EA779.jpeg
7FBAAE34-A225-4159-95FE-77C6586EA779.jpeg (1.57 MiB) Viewed 482 times
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