Turntable speed

[John]

I downloaded the RPM app and checked my three turntables.

Initial readings LP12 = 33.54
Technics SL-1200 Mk2 = 33.56
Rega Planar 2 = 34.17

I adjusted the LP12 and now have it pretty much spot on at 33.35 if the RPM app is to be believed.

I’m surprised the Technics is off as the strobe at the Zero setting is sitting steady so I’m thinking there might be some type of speed calibration that is possible. Both the Rega and Technics are 1988 vintage, not sure if there’s a way to calibrate the speed of the Rega but I’d appreciate any input.

 

[hifi-dog]

Have you calibrated the app to the gyro in your phone? You may have to pay for the full version to do this but it will give better and consistent results.

 

[Tony L]

Here’s my TD-124:

That’s with the built-in strobe set, so calibrated from mains frequency. The wow and flutter is the interesting thing IMO. That’s a key part of what separates the good turntables from the less good ones. iPhone 13.

PS There’s another thread somewhere, maybe one of the blue-belt ones.

 

[John]

Have you calibrated the app to the gyro in your phone? You may have to pay for the full version to do this but it will give better and consistent results.

I ran through the 10 free uses of the app so I maybe forced to get the full version. I’m not surprised the Rega was running fast as that seems to be the norm but I’m surprised about the Technics running fast. My thought was that DD decks ran spot on.

 

[myles]

I'd be looking to cross reference against a strobe disc or something regarded as reliable.

 

[John]

Here’s my TD-124:

That’s with the built-in strobe set, so calibrated from mains frequency. The wow and flutter is the interesting thing IMO. That’s a key part of what separates the good turntables from the less good ones. iPhone 13.

PS There’s another thread somewhere, maybe one of the blue-belt ones.

What app is that?

 

[Tony L]

What app is that?

Turntable Speed (App Store).

 

[John]

Have you calibrated the app to the gyro in your phone? You may have to pay for the full version to do this but it will give better and consistent results.

So I went ahead and purchased the full version and calibrated it to my iPhone 8. The calibration was needed.

Numbers went down so I needed to re-set the speed on my LP12, it’s now 33.34 +0.01%, w/f = 0.10%

The Technics went from 33.56 to 33.44 +0.32%, w/f = 0.11%

The Rega went from 34.17 to 34.1 +2.29%, w/f = 0.25%

 

[Nagraboy]

Here’s my 124. I had to place the phone next to the spindle so not 100% accurate. The deck is being fed 200V via an external PSU:

 

[John]

Turntable Speed (App Store).

I downloaded the Turntable Speed app and the numbers agreed with the pre-calibration numbers I was getting from the RPM app. Didn’t see anyway to calibrate the gyroscope on the phone to the Turntable Speed app. At least the pre-calibration numbers agree which gives me some confidence in these iPhone apps.

 

[myles]

Turntable Speed (App Store).

That is a good app.

 

[tpetsch]

Don't forget to account for stylus drag, it's true, test the speed with the stylus playing in the groove and then again without an you'll get different results depending on the resistance of track you play. Find an average.. FWIW, I use a Timeline SE Turntable Speed Strobe and it's easy to see any speed inconsistencies with it on the fly.

 

[John]

Just watched a YouTube video where they replaced a capacitor inside an older Rega. There’s only two parts to the power supply with no adjustment for the speed. That takes care of that. Still wondering about the Technics and wondering if mine is the only one not running at 33.33.

 

[Darren]

I’m surprised the Technics is off as the strobe at the Zero setting is sitting steady so I’m thinking there might be some type of speed calibration that is possible. Both the Rega and Technics are 1988 vintage, not sure if there’s a way to calibrate the speed of the Rega but I’d appreciate any input.

Is there a reason why these apps are better/more accurate than a strobe disc/platter? Its not as though your smart phone was ever meant for this role.

 

[Big Tabs]

Is there a reason why these apps are better/more accurate than a strobe disc/platter? Its not as though your smart phone was ever meant for this role.

That is what I was thinking

 

[John]

Is there a reason why these apps are better/more accurate than a strobe disc/platter? Its not as though your smart phone was ever meant for this role.

Are you saying the Technics is showing a true 33.33 and the two apps which pre-calibration agree with themselves are off?

It’s an interesting thought because my initial readings with the app showed the Technics at 33.56 and the Linn 33.54, very close to one another.

 

[Tony L]

Is there a reason why these apps are better/more accurate than a strobe disc/platter? Its not as though your smart phone was ever meant for this role.

With the minimal error I got that could well just be me not dialling it in perfectly, in fact I’m pretty sure this is the case. It isn’t something that bothers me in the slightest as it is so easily adjusted on the fly (the 124 has a strobe and easy fine speed adjust). All I was interested in is the wow and flutter figures, which are exceptionally good (i.e. not that far off things like a SME 20, SL1200G etc, and with some real torque too).

PS I’d be interested to see a figure for the Rega actually playing a typical record. They may well have factored-in some stylus drag. The SL1200 will have more than enough torque not to care in the slightest, but I’d expect it to effect low-torque belt drive decks, albeit to a fairly minor degree.

 

[Darren]

All I'm saying, I guess, is that being 'electronic' or 'software driven' in no way equates to any level of inherent accuracy to me. Are the accelerometers used in phones calibrated in in any way to a fine degree of accuracy? I bet not.
No expert and happy to be proved wrong.

 

[John]

With the minimal error I got that could well just be me not dialling it in perfectly, in fact I’m pretty sure this is the case. It isn’t something that bothers me in the slightest as it is so easily adjusted on the fly (the 124 has a strobe and easy fine speed adjust). All I was interested in is the wow and flutter figures, which are exceptionally good (i.e. not that far off things like a SME 20, SL1200G etc, and with some real torque too).

PS I’d be interested to see a figure for the Rega actually playing a typical record. They may well have factored-in some stylus drag. The SL1200 will have more than enough torque not to care in the slightest, but I’d expect it to effect low-torque belt drive decks, albeit to a fairly minor degree.

Here you go from Turntable Speed app. What numbers are you interested in?

 

[Tony L]

Here you go from Turntable Speed app. What numbers are you interested in?

Curious if the actual speed slows when playing a typical record at a typical tracking weight (I’m assuming your 34.12rpm is unloaded). If you use a reel of packing tape or whatever on the record label you can position the phone right over the spindle thus keeping the playing surface free. My suspicion is the drag will slow it to something closer to 33.3 rpm.