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Old 3rd January 2018, 03:46 PM   #841
billshurv is online now billshurv  United Kingdom
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Turntable speed stabilty
I guess you haven't read back many posts. see post 823
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Old 3rd January 2018, 04:00 PM   #842
super10018 is offline super10018  United States
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There may be some confusions. My bad. However, putting anything between cartridge and head shell won't do the trick.
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Old 3rd January 2018, 04:07 PM   #843
billshurv is online now billshurv  United Kingdom
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Turntable speed stabilty
This is very true. Hasn't stopped people who should know better selling devices to do this though.

The Cartridge Man Isolator for example

Edit: And I am ignoring your comment about pivoted damping at the bearings as I really cannot afford this . SME FDIV Damper kit

Last edited by billshurv; 3rd January 2018 at 04:23 PM.
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Old 3rd January 2018, 07:25 PM   #844
diyrayk is offline diyrayk  United States
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Quote:
Originally Posted by diyrayk View Post

In designing and building my own unipivot arm, I put most of the damping in the vertical direction for warp damping, and less damping in the horizontal direction, instead relying on the zero offset angle of my linear tracker to reduce FM from horizontal scrubbing.

Ray K
Quote:
Originally Posted by Hans Polak View Post
Hi Ray,

Thanks for your contribution.
One question: How exactly did you put damping in the vert direction to your own arm ?

Hans
Hans,

Damping is at the pivot, not especially different from the way damping has been implemented on other unipivots. In my case it was done by selecting the dimensions of the cylindrical bearing cup (part B in the photo) thatís submerged in a silicone oil bath in the pivot base (part C in the photo). For vertical motion the cylinder sloshes the silicone bath and sees significant damping effect. For horizontal motion the cylinder rotates axially in the silicone bath and the damping effect is less. The design was done empirically, so I am unable to offer any design calculations. Basically seat-of-the-pants engineering that worked out eminently well.

Ray K

http://www.diyaudio.com/forums/attac...1&d=1515010686
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File Type: jpg Parts Breakdown.jpg (142.2 KB, 110 views)
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Old 3rd January 2018, 09:53 PM   #845
Hans Polak is offline Hans Polak  Netherlands
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Quote:
Originally Posted by diyrayk View Post
Hans,
Damping is at the pivot,
Ray K
Impressive Ray,
thanks

Hans
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Old 4th January 2018, 09:14 AM   #846
gpapag is online now gpapag  Greece
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Turntable speed stabilty
Default Re M97xE brush effect

Shure M97xE (on Pro-ject Debut Carbon arm) resonance test.
Brush up vs brush down
Shure TTR117 test record.
Source:
YouTube

Apply your analysis tools

brush up
Dropbox - Brush up.wav

brush down
Dropbox - Brush down.wav


George
Attached Images
File Type: png Brush up.PNG (124.6 KB, 78 views)
File Type: png Brush down.PNG (124.9 KB, 75 views)
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Old 4th January 2018, 01:43 PM   #847
scott wurcer is offline scott wurcer  United States
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Quote:
Originally Posted by gpapag View Post
Shure M97xE (on Pro-ject Debut Carbon arm) resonance test.

Apply your analysis tools
George the analysis tool seems to have trouble labeling the low decade(s)? Getting flawless plotting of log axes especially with partial decades at either or both ends is a special exercise.
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Old 4th January 2018, 01:46 PM   #848
Hans Polak is offline Hans Polak  Netherlands
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Here is the first output, 5 Hz modulating 2989 Hz and 2380 Hz.
With Brush Up, waving is considerable, almost exclusively vertical resonance (not separately shown here).
Taking the brush down, suppresses the resonance and waving because of that to a great degree.
IM distortion becomes 2.5 dB less, not as much as expected when looking at the waving.
More to follow.


In the spectra below, light green is the IM spectrum and cyan the spectrum of the input signal waving caused by hor and vert resonance.

Hans
Attached Images
File Type: jpg Brush up 1.jpg (250.9 KB, 71 views)
File Type: jpg Brush down 1.jpg (230.2 KB, 68 views)

Last edited by Hans Polak; 4th January 2018 at 02:03 PM.
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Old 4th January 2018, 02:00 PM   #849
Hans Polak is offline Hans Polak  Netherlands
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George,

What's the lower -3dB point of your recording chain, from TT to digital.
My question is because it effects the waving of the signal in the .wav file.

Hans
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Old 4th January 2018, 04:28 PM   #850
Hans Polak is offline Hans Polak  Netherlands
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Now for 6 Hz plus both carriers at 2.4 and 3 KHz, brush up and brush down again showing IM for 3 LP revolutions.
Waving of LP input signal is again considerably lower with brush down, but with brush down IM at 5Hz is only 2.8 dB less, and still above the critical threshold of 0.1%.


Hans
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File Type: jpg Brush 2.jpg (640.7 KB, 21 views)
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