platter speed, test disk & strobes

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nilsatisnisioptimum
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platter speed, test disk & strobes

Unread post by nilsatisnisioptimum »

Given my insatiable curiosity its a surprise its taken me so long to want to check the speed of my Planar 8. I have the RPM app on my android phone which suggests its in the right area but my ears had already confirmed that. This has not stopped me wanting to know what it truly is and make adjustments if required.

eBay & Amazon have no end of stroboscopic test disks, ranging from £10 to well beyond however the choice of test disks with a strobe light is tiny and far the most part the strobe light is the expensive part of the equation --- that being the case is it possible to accurately calibrate my platters speed with only the test disk or with some other form of light source instead of the strobe light (I have no end of LED lights for camping, fishing, cycling, running etc) plus UV torches for another hobby. Thanks Paul
Airlink BPS 3110S with LDA DC filter, Rega Planar 8 with Apheta 3, LDA MCJ3 phono, NVA P90 SA MK2, NVA A70 X 2, Cambridge Audio CXC, Denafrips Ares2 DAC, Meridian 204 FM tuner, Audio Technica ATH 70 cans, NVA Cubix & LS6 & Oppo 2 cans and Activo CT10 with Tidal on the move

Daniel Quinn
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Re: platter speed, test disk & strobes

Unread post by Daniel Quinn »

I use a laser tachometer. £18 from China. Its as accurate as it gets.
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nilsatisnisioptimum (Tue Jun 30, 2020 7:18 pm)

Geoff.R.G
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Re: platter speed, test disk & strobes

Unread post by Geoff.R.G »

You have a strobe in every room of your house, domestic lighting flickers on and off 100 times per second (Once on the positive half of the wave and once on the negative). A camping LED, driven by a DC supply will be useless.

The accuracy of the UK mains frequency is generally accepted to be very good so a simple strobe disc is really all you need. However, if you have a spare oscilloscope hanging around you could hook up a high quality signal generator set to 1KHz to the X input and play a 1KHz test tone from a test record and put the output on the Y input, the resulting display should be a circle any speed irregularity will be shown up as distortion of the display. Look up lissajous figures on Google.
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nilsatisnisioptimum (Tue Jun 30, 2020 7:18 pm)

nilsatisnisioptimum
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Re: platter speed, test disk & strobes

Unread post by nilsatisnisioptimum »

Cheers Geoff, my mains supply which I have tested over about a week is ok, it tends to dip at peak times to 233/4 but for the rest of the time its usually 237/8. I will look up the your suggestion and report back 👍
Airlink BPS 3110S with LDA DC filter, Rega Planar 8 with Apheta 3, LDA MCJ3 phono, NVA P90 SA MK2, NVA A70 X 2, Cambridge Audio CXC, Denafrips Ares2 DAC, Meridian 204 FM tuner, Audio Technica ATH 70 cans, NVA Cubix & LS6 & Oppo 2 cans and Activo CT10 with Tidal on the move

Geoff.R.G
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Re: platter speed, test disk & strobes

Unread post by Geoff.R.G »

nilsatisnisioptimum wrote:
Tue Jun 30, 2020 2:06 pm
Cheers Geoff, my mains supply which I have tested over about a week is ok, it tends to dip at peak times to 233/4 but for the rest of the time its usually 237/8. I will look up the your suggestion and report back 👍
The turntable speed is measured using the mains FREQUENCY, the voltage has nothing to do with the way the strobe operates. The suggestion of using an oscilloscope was slightly facetious, but it does work.

nilsatisnisioptimum
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Re: platter speed, test disk & strobes

Unread post by nilsatisnisioptimum »

Its ok. I should have put my mains voltage comment in the context of once its set, the speed should be relatively stable because of the minimal voltage fluctuations.
Airlink BPS 3110S with LDA DC filter, Rega Planar 8 with Apheta 3, LDA MCJ3 phono, NVA P90 SA MK2, NVA A70 X 2, Cambridge Audio CXC, Denafrips Ares2 DAC, Meridian 204 FM tuner, Audio Technica ATH 70 cans, NVA Cubix & LS6 & Oppo 2 cans and Activo CT10 with Tidal on the move

nilsatisnisioptimum
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Re: platter speed, test disk & strobes

Unread post by nilsatisnisioptimum »

Daniel Quinn wrote:
Tue Jun 30, 2020 1:12 pm
I use a laser tachometer. £18 from China. Its as accurate as it gets.
Thanks for that, this sounds very interesting, do you by chance have a link ?
Airlink BPS 3110S with LDA DC filter, Rega Planar 8 with Apheta 3, LDA MCJ3 phono, NVA P90 SA MK2, NVA A70 X 2, Cambridge Audio CXC, Denafrips Ares2 DAC, Meridian 204 FM tuner, Audio Technica ATH 70 cans, NVA Cubix & LS6 & Oppo 2 cans and Activo CT10 with Tidal on the move

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Re: platter speed, test disk & strobes

Unread post by Hannes-Gregor »

Geoff.R.G wrote:
Tue Jun 30, 2020 7:05 pm
nilsatisnisioptimum wrote:
Tue Jun 30, 2020 2:06 pm
Cheers Geoff, my mains supply which I have tested over about a week is ok, it tends to dip at peak times to 233/4 but for the rest of the time its usually 237/8. I will look up the your suggestion and report back 👍
The turntable speed is measured using the mains FREQUENCY, the voltage has nothing to do with the way the strobe operates. The suggestion of using an oscilloscope was slightly facetious, but it does work.
Geoff is right. You only need a strobe disc. The rest will do a lamp of your choice.

Daniel Quinn
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Re: platter speed, test disk & strobes

Unread post by Daniel Quinn »

Just look on ebay, there are loads to choose from, some more expensive but in the UK.

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Latteman
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Re: platter speed, test disk & strobes

Unread post by Latteman »

Vinyl engine has a free download- I printed it and laminated onto a 7” single.
I then use a strobe app on my phone for 50hz
Analogue- DIY turntable from Thorens TD321, ARB unipivot Arm; Nagaoka SB mp200- phono 1
Digital Sources- Denon CEOL streamer/Cdp; iPhone Xr; Airport Express Cat7 & 8
Amplification-NVA P20 (modified) & A20LE (👍🏼)
Speakers- Diy Cubes; Ls6
Mini BMU to dc blocker

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