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Wow and flutter 'meter', etc

It's possible that it's the machining of the sub-platter as it does have a strong ringing mode. However, it would be at a much higher frequency than this and I did check it with a dial gauge at the time and found no issue. I'll see if I can check it again.
 
A sticky patch on the platter, giving the belt a "twang" every revolution could excite the turntable resonance, looking like this
 
Just to let people know that I have now put up a ROX-Filer/Linux version of my wow and flutter program which can be got from the links on
http://www.audiomisc.co.uk/software/index.html

The source code is provided as usual, and it can be run as-is on other Linux systems in the usual ways. A Help.txt file is provided.

Note for anyone wanting to port or improve. Start with this rather than the RISC OS version as this is based on using GCC. The RO compiler I use has some subtle quirks which can affect results if you don't correct for them when converting the code. In this case the significant one being that RO assumes a 'char' is unsigned by default, but GCC needs you to be specific about an 'unsigned char' for some of the conversions to work correctly!

At some point I will add 'veusz' file generation to make plotting results easier.
 
I've still got that inductor box that I used to run in-line with my Armageddon. I haven't tried it with the new power supply but could do easily enough. Worth a try do you think?
 
I did a bit of looking into it, the Analogue productions test lp was cut on a Neumann VMS 80 at sterling sound.

On here:http://sterling-sound.com/mastering/vinyl/#3

And I quote "The VMS 80 computer divides each rotation of the platter into sixteen increments"

16 increments works out to be 8.88hz, visible on most the spectrums, particularly the Yamahas. It also showed up on my DIY turntable plot.

It seems the source of the 16 bumps has been located as this plot was made using the Analogue Productions test record.
 
I guess I'll have to get hold of a copy of the 'clearaudio' test LP.

Apart from that, the HFN LP, and the AP one, anyone know of other test LPs current available new that have test tones?
 
Dunno. But by a weird co-incidence I spent yesterday helping someone to use the program I wrote to get the results they needed! Looks like not only turntables can employ synchronisity! :)
 
FWIW there was a design for a W & F meter in Electronics World around 2000 ish.... it will be available on the interweb thingy.
 
I vaguely remember Ortofon making a box back in the late 70’s maybe early 80’s
that when used with their test disc would give a turntable speed print out (maybe a W&F print out as well).
 
I used to have one of those when I was a kid. Great fun, it was.

il_fullxfull.285261139.jpg


With a bit of practice you can make nice patterns, like Paul's.

Joe
Damn , you beat me to it !
 
I assume that these days no developer needs one of the old meters when a suitable ADC and computer can do as good a measurement or better via software.
 


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