Wow and Flutter measurements like you've never seen before! Maybe...

[Balle Clorin]

@Balle Clorin What is the actual IMU chip in the Shake'n'spin? The data sheet will tell all.

The 'data' captured is most likely in the noise/error/minimum floor of the A/D converters in the IMU and all you are doing when filtering is looking for a 'trend', not an absolute indicator of true wow or flutter.

Minute turntable variations in rotational velocity are at the absolute bottom end of the most sensitive ranges of these chips- they aren't designed or capable of accuracy or repeatability in measurements- they are mass produced for phones, tablets and drones, not precision turntables.

Do not know what IMU, anyway it clearly show different and repeatable results for all the 30 turntables I have measured. I do not always trust the calculated DIN W&F though

 

[Speedskater]

In another mode, could the Go Direct Sensor be used to measure turntable isolation devices?
Maybe on a DIY shaker table (a cheap subwoofer).

 

[Balle Clorin]

You already have that. Rest your cartridge on a stationary record and do a recording ..

 

[Luca Sorrentino]

@Balle Clorin Can the shakenspin acquire an arbitrary amount of data/samplerate?
For example 5 minutes and save it in cvs in your pc?

 

[restorer-john]

I do not always trust the calculated DIN W&F though

Did you get a copy of the 6 NAB calibrated flutter files I uploaded a while back? They can be used to cross-check your app for flutter accuracy across two standards.

 

[Balle Clorin]

Skaknspin cannot interpret sound. I did post some ovelay of phone app and test record in The Fun with vinyl measurements thread., the shape was quite similar, but the inherent record WF is at the same level as a good turntable and makes comparison difficult in any case

 

[Luca Sorrentino]

In addition to my previous calculations, I've "reconstructed" speed variation and polar plots from the FFT spectrum, this permits to complete filter out the white noise of the sensor.
It's a work in progress. Two turns are represented.

 

[livinon2wheels]

While much of what you guys have posted here is over my heads, I have a couple of questions regarding some of the vintage turntables and their comparison to currently produced models. The first question is: Have the measuring methods changed for measuring W&F since the days of the Technics SL1 DD turntable? The reason I am asking is it seems that many TT produced today if they offer a W&F spec at all appear to measure much worse than the SL1 did. That particular model was one I used to own back in the day and it was considered pretty darn good for the time. What I do not understand is the apparent poor performance of modern TT models in the under $1000 class. So is this disparity in performance due to a different measurement standard being applied today as opposed to 1985's approach or an actual performance degradation in that price class?

 

[morillon]

While much of what you guys have posted here is over my heads, I have a couple of questions regarding some of the vintage turntables and their comparison to currently produced models. The first question is: Have the measuring methods changed for measuring W&F since the days of the Technics SL1 DD turntable? The reason I am asking is it seems that many TT produced today if they offer a W&F spec at all appear to measure much worse than the SL1 did. That particular model was one I used to own back in the day and it was considered pretty darn good for the time. What I do not understand is the apparent poor performance of modern TT models in the under $1000 class. So is this disparity in performance due to a different measurement standard being applied today as opposed to 1985's approach or an actual performance degradation in that price class?

2eme....
(often just tinkering to feed the "revival" fashion of the LP.... like many recent records "lp"..DDA etc)

 

[Balle Clorin]

While much of what you guys have posted here is over my heads, I have a couple of questions regarding some of the vintage turntables and their comparison to currently produced models. The first question is: Have the measuring methods changed for measuring W&F since the days of the Technics SL1 DD turntable? The reason I am asking is it seems that many TT produced today if they offer a W&F spec at all appear to measure much worse than the SL1 did. That particular model was one I used to own back in the day and it was considered pretty darn good for the time. What I do not understand is the apparent poor performance of modern TT models in the under $1000 class. So is this disparity in performance due to a different measurement standard being applied today as opposed to 1985's approach or an actual performance degradation in that price class?

No change, same standard, it it just that most present TT have crappy speed performance , I have a cheap low end Sony PS-212 plastic player from approx 1980 it measures better than most TT sold today. I have the proper tools to do correct measurements and compare.

note most phone apps do a kind of maximum variation value , and do not show a DIN w&f weighted number. And the Japanese JIS number is RMS to make the value look better/lower than DIN even when the variation is the same.

Anyone can use the phone app on old DD from the. 70-80s and compare with present offerings , I can tell you that in 4 of 5 times the old garage sale DD TT will beat a random new TT made today.
The rule is measure and compare before you buy.

Price of TT have no correlation with speed performance. A 500 usd TT can have better speed performance than a 50 000 usd TT. I know since I have measured many …

 

[Luca Sorrentino]

Have the measuring methods changed for measuring W&F since the days of the Technics SL1 DD turntable?

In my understanding the watershed was measuring with a test record or use directly the tacho signal. The former is less precise because includes the irregularities, warps, click and pops, tonearm resonances and so on, the second permits to isolate the platter rotation alone.
Nowadays, like I did at home, we have plenty of low cost accelerometers to deep dive any subtle periodic speed variation like never before.
Anyway, this thread was just to have fun, and I have no clues on whether certain amount, or type, of W&F is audible or not.

 

[livinon2wheels]

No change, same standard, it it just that most present TT have crappy speed performance , I have a cheap low end Sony PS-212 plastic player from approx 1980 it measures better than most TT sold today. I have the proper tools to do correct measurements and compare.

note most phone apps do a kind of maximum variation value , and do not show a DIN w&f weighted number. And the Japanese JIS number is RMS to make the value look better/lower than DIN even when the variation is the same.

Anyone can use the phone app on old DD from the. 70-80s and compare with present offerings , I can tell you that in 4 of 5 times the old garage sale DD TT will beat a random new TT made today.
The rule is measure and compare before you buy.

Price of TT have no correlation with speed performance. A 500 usd TT can have better speed performance than a 50 000 usd TT. I know since I have measured many …

Many thanks for your thorough explanation. If I ever replace the two turntables I lost in last April's fire I suspect I will buy something used, though the 1500ish dollar Technics made today looks pretty good. Good equipment is getting frightfully expensive, especially if you are talking about surround processors and turntables. Its crazy what a good high end cartridge costs now...upwards of a $1000 just for a cartridge....that's nuts!

 

[LewisWaddo]

Excellent work! I, by chance, grabbed a GL75 for £30 years ago. I performed a few upgrades on it, and it performed way better than I expected, even better than my far more expensive turntables. Would love to see more of your analysis on other setups.

 

[livinon2wheels]

That old Lenco sure looks good. I appreciate the 'vintage' experience. Maybe not as a daily driver, but the ability to spin a few platters when the urge materializes is satisfying. For now that remains an unrealized experience.

 

[Luca Sorrentino]

Excellent work!

Thank you!

Would love to see more of your analysis on other setups.

Here you have ie a Sony PS-X800 compared with the same Lenco that in the meanwhile has slightly increased it's nominal speed:

Two different Sony PS-X800 compared:

One of the Sony before motor trimmer adjusting:

An interesting Mitsubishi DP-EC7, a DD without quartz PLL kindly send me by another user that decide to use my same method:

A Thorens TD-160 from same user, at that time it wasn't still implemented auto scaling function in polar plots:

Cheers,
Luca

 

[LewisWaddo]

Do you have access to a technics 1200g? Haha that’s my main TT. I wonder if the price is justified..?

 

[Luca Sorrentino]

Do you have access to a technics 1200g

I don't unfortunately. If you're in the US you could buy a sensor and measure by yourself, it's relatively inexpensive, I could guide you.
I would be curious to check the speed of a modern tt moved probably by a sensorless FOC inverter or something like that, different technology respect to the old hall sensors quartz PLL.
Today cheapest Hampin use that principle too in my understanding.
Hope build construction of your Technics is aligned with it's price tag, especially for the tonearm and the chassis that have same importance of speed stability.

 

[LewisWaddo]

I don't unfortunately. If you're in the US you could buy a sensor and measure by yourself, it's relatively inexpensive, I could guide you.
I would be curious to check the speed of a modern tt moved probably by a sensorless FOC inverter or something like that, different technology respect to the old hall sensors quartz PLL.
Today cheapest Hampin use that principle too in my understanding.
Hope build construction of your Technics is aligned with it's price tag, especially for the tonearm and the chassis that have same importance of speed stability.

I’m based in the U.K., and definitely up for sourcing a sensor.

 

[JP]

I would be curious to check the speed of a modern tt moved probably by a sensorless FOC inverter or something like that, different technology respect to the old hall sensors quartz PLL.

It's principally all the same - sensors for rotor position for commutation (hall, variable reluctance, etc.) and a speed sensor. Those used to be magnetic frequency generators, and on 'tables like the GR it still is, while their "high end" tables like the G and 10R use an optical encoder.

 

[Luca Sorrentino]

It's principally all the same

Uhm, this is a Reloop RP4000 and effectively have same principle of the old ones, I'm quite sure I've seen a pcb picture of a modern Technics and that one was moved by a Renesas mcu, that in some manner synthesize waveforms to feed the motor coil.
I hypothesize something like an inverter with FOC control, but at the same time I'm perplexed about EMI and audible effect of such a solution in a turntable, maybe instead of driving the motor with the high frequency squares wave exiting from the inverter, they put a LPF before.