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Wave Kinetics NVS Reference Turntable Review on Positive Feedback
Some people prefer the sound of SET with 0.5% distortion. What's your point? My post was not about opinions it was about facts, measurements and published specs. The encoder is solidly coupled to the platter and provides feedback to the controller. It is the most reliable indication of the...- Phoenix Engineering
- Post #130
- Forum: Turntables
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OMA on turntables
That was punishing to watch; i couldn't make it past 11:00. I think Johnathon likes the sound of his own voice. Six minutes of that monotone delivery before he even mentioned anything about the K5, then no real details. You could condense the 14 min video down to 5 seconds: The K5 is a...- Phoenix Engineering
- Post #2
- Forum: General Analog Audio Forum
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John DeVore on the Grey Market and OCD Mikey
When I was still in high school, my father once said to me: "Most people are honest, but if you make it easy enough for them to steal, even the most honest of people will be tempted to do so". When I started selling synthesized mains PSUs for turntables in 2014, I was a start up in this...- Phoenix Engineering
- Post #170
- Forum: General Audio Forum
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Esoteric Grandioso T1 turntable arrives; G1X Master Clock coming.
Cogging will not be affected by the drive signal; in fact, PWM is the preferred way to drive these motors as it allows smaller changes and slower speed where sinewave drive does not. A good analogy is model trains; if you use DC voltage to control the speed, the train stops moving at a much...- Phoenix Engineering
- Post #492
- Forum: Turntables
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Esoteric Grandioso T1 turntable arrives; G1X Master Clock coming.
You've posted that before, but it doesn't show a measurement; Fremer used to show the actual data results in the form of a graph with actual readings. What exactly does "comparable" mean quantitatively? It's really more of an opinion. Even the graphs he used to post can be suspect as they...- Phoenix Engineering
- Post #482
- Forum: Turntables
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Esoteric Grandioso T1 turntable arrives; G1X Master Clock coming.
It does appear to be some form of cogging, but the rate of oscillations doesn't look right. If it were the rotor/platter interface cogging, it would occur at every "tooth" which would be much more often than what I see to be ~20° per oscillation. If it were the motor cogging, it would be even...- Phoenix Engineering
- Post #480
- Forum: Turntables
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Esoteric Grandioso T1 turntable arrives; G1X Master Clock coming.
Peter- I've seen this video before and the back and forth at start up that you called attention to. I don't think that is cogging. Originally, I thought it was a phenomenon that occurs with 3 phase motors at start up due to the position of the motor's rotor being unknown, but that is usually...- Phoenix Engineering
- Post #476
- Forum: Turntables
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Esoteric Grandioso T1 turntable arrives; G1X Master Clock coming.
Mike- Allow me to correct some misdirection on your part: I do not mfr TT related products; I closed down commercial operations at the end of 2016. I retired from my first company in 2010 and regretted coming out of retirement in 2014 to mfr power supplies for TTs. Since then, I have...- Phoenix Engineering
- Post #473
- Forum: Turntables
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Esoteric Grandioso T1 turntable arrives; G1X Master Clock coming.
It might be worth trying the Amazon offering; there is little downside at $17. It would be interesting to see if any listeners could tell the difference in a blind A-B-C-X test (Internal osc/G1X/Amazon).- Phoenix Engineering
- Post #432
- Forum: Turntables
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Esoteric Grandioso T1 turntable arrives; G1X Master Clock coming.
Just saw the price on the G1X, YIKES! $30K for a frequency reference seems a tad steep. Amazon is selling 10MHz OCXOs with frequency accuracy of 1PPB (1 x 10-9) for $17: Amazon OCXO That's 10x more accurate than the G1X (@.01 PPM). For $4K you can get a lab quality reference that is locked to...- Phoenix Engineering
- Post #430
- Forum: Turntables
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Esoteric Grandioso T1 turntable arrives; G1X Master Clock coming.
Measurements are just tools; just like hand tools or power tools, if they are used incorrectly, you get bad results. That doesn't (and shouldn't) diminish the listening experience, it should compliment it. Each has its proper place; even an artist uses tools. :)- Phoenix Engineering
- Post #428
- Forum: Turntables
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Esoteric Grandioso T1 turntable arrives; G1X Master Clock coming.
Another view of the same phenomenon as above. This is the audio spectrum of the open loop Condor controller; if the motor was perfect, you would see a single peak at 3125Hz with no sideband, but because of the speed (frequency) modulation, you have numerous peaks every 20Hz: This is the...- Phoenix Engineering
- Post #425
- Forum: Turntables
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Esoteric Grandioso T1 turntable arrives; G1X Master Clock coming.
The "motor resonance" you feel is the cogging I referred to in my previous post. All PM motors with iron cores will have it. Some motors are better than others; the BLWS 3 phase motors that SOTA uses are easily 30dB lower vibration than most common (Hurst) AC sync motors, but it is still...- Phoenix Engineering
- Post #424
- Forum: Turntables
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Esoteric Grandioso T1 turntable arrives; G1X Master Clock coming.
Mike- Beautiful table and interesting design. I'm glad it is meeting (exceeding?) your expectations. Their website is heavy on marketing fluff and light on details, but several items I was wondering about have shown up in reviews and other sites. The MagneDrive system is synchronous so the...- Phoenix Engineering
- Post #422
- Forum: Turntables
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Do Mobile Fidelity Vinyl Re-issues Have a Digital Step in the Process?
I don't think this scenario of misrepresenting information and products is limited to Music Direct, although it seems to be singularly ubiquitous in the audio industry. According to the FTC, there are 3 criteria that should be met before they will investigate deceptive advertising: 1. Was a...- Phoenix Engineering
- Post #428
- Forum: General Analog Audio Forum
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VPI HW19 Mk3 Motor speed issue
OK, I'm confused. If the actual OD of the 33 RPM spindle is 18.2mm, then it would need to be 500 RPM. I forgot about those pulleys with only a single groove. With a speed controller, you do not move the belt, the controller changes frequency to move between 33/45 RPM.- Phoenix Engineering
- Post #21
- Forum: VPI Turntables and Tonearms Forum
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VPI HW19 Mk3 Motor speed issue
I believe with the dimensions you posted it would be a 12 pole motor running at 500 RPM (600 US)? Also, I would not measure at the bottom of the groove as the belt will ride somewhere in between the groove bottom and OD of the pulley. The 500 RPM pulley is tapered and the lower grooves will...- Phoenix Engineering
- Post #18
- Forum: VPI Turntables and Tonearms Forum
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VPI HW19 Mk3 Motor speed issue
It's easy to compute: (Pully Dia + T/2)/(Platter Dia + T/2) = 33.333/Motor RPM. Where T= belt thickness Rearranging: Motor RPM = 33.333 * (Platter Dia + T/2)/(Pulley Dia + T/2) The line voltage in Sweden is 50Hz, correct? So the motor speed will be 250 RPM or 500 RPM (RPM=120*Freq/# motor...- Phoenix Engineering
- Post #6
- Forum: VPI Turntables and Tonearms Forum
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The language of Reproduction and the language of Music.
"Demonized" may be a bit strong, but I have been attacked on another site for using the acronym "PRaT" (Pace, Rhythm and Timing). While technically incorrect in the way it is often used, it enjoys a certain cachet among audio enthusiasts and IMO has some utility. Reading this thread, I've come...- Phoenix Engineering
- Post #120
- Forum: General Audio Forum
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What's Everyone Reading
Fascinating book, I could hardly put it down. This edition is from 2018 but it perfectly describes what is happening in our society currently. I highly recommend the 2018 edition, there are 2 additional chapters vs the 2014 edition; hopefully, he updates the book again soon. It is about as...- Phoenix Engineering
- Post #951
- Forum: Novels, Recommended Reading
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List of Turntable Manufacturers
@Amr- Unfortunately, I've never auditioned the FnR table. I did some work on a motor controller for them, but ultimately they chose a different solution.- Phoenix Engineering
- Post #148
- Forum: Turntables
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List of Turntable Manufacturers
Hi John- Great job putting together the list. How about adding Fern and Roby: https://www.fernandroby.com/products/details/the-tredegar-turntable-1- Phoenix Engineering
- Post #146
- Forum: Turntables
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Natural Sound
This was theorized, but was audible speed "hunting" ever proven or measured? A tachometer would not measure it but demodulating a 3150Hz tone from a test record might show this, depending on the amount frequency shift and the rate of shifting, by looking at the amplitude of the demodulated...- Phoenix Engineering
- Post #2,286
- Forum: Members' Systems
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Natural Sound
Categorize them as far as what? Speed accuracy and stability? It all depends on the implementation. DC motors require compensation (current feedback) or there will be a negative torque/speed slope. AC synch motors have constant speed, but a belt driven platter does not because of belt creep...- Phoenix Engineering
- Post #2,279
- Forum: Members' Systems
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Natural Sound
Yeah, that makes sense. Most of those aren't frequency agile or very limited if they are; not a lot of utility if you want to control speed with it. That explains your comments about wave shape and frequency. It's easier and cheaper at low voltages and chip amps are readily available...- Phoenix Engineering
- Post #2,267
- Forum: Members' Systems
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Natural Sound
I'm OK with everything in your post except this. I've dissected dozens of designs and none of them are synchronized to the mains; stable frequency is the most important factor, it is their raison d'etre. I've designed many of these supplies and all of them use a crystal reference, as do most...- Phoenix Engineering
- Post #2,264
- Forum: Members' Systems
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Natural Sound
IME, there is a correlation. It's not the only determining factor, but it is one of many components. Mains accuracy can vary considerably, not only with geography, but with time of day. I don't agree with your assessment and apparently, neither do a lot of users and mfrs. Regenerative power...- Phoenix Engineering
- Post #2,261
- Forum: Members' Systems
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Natural Sound
A wee bit ** of sarcasm professor? Touché! ;) ** I think even Sheldon Cooper would've caught that one...- Phoenix Engineering
- Post #2,258
- Forum: Members' Systems
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Natural Sound
I did read the first posts and do understand the main point. Your points were simple and I addressed them directly. I didn't systematically change or misrepresent your points, I quoted them verbatim. You were disparaging the use of anything other than a strobe disc as a "gadget" with little...- Phoenix Engineering
- Post #2,257
- Forum: Members' Systems
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Natural Sound
So how do you quantify speed instability with a strobe disc? The spots or lines move, but what is a "good" reading and what constitutes "bad"? What is the "needed" level of accuracy using a strobe disc? Perhaps you could enlighten us on how to interpret the results of looking at a disc...- Phoenix Engineering
- Post #2,249
- Forum: Members' Systems
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