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Turntable Masterclass by Mark Doehmann

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A heads up for any one going to the Australian Audio & AV show 2013.

 

http://www.chestergroup.org/chester-group-news/australian-audio-av-show-13/australian-show-main-page/turntable-masterclass-by-mark-doehmann.html

 

I think this would be a very interesting seminar picking Mark Doehmanns brain, I hope this is going to be tape recorded and posted for all of us not being able to make it.

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I attended his presentation on Friday and it was very informative especially the info around the cutting lathe. He went into relative detail about the lathes limitations where specific signals were injected into the cutting head to counter the heads resonant frequency through to the bearing and vacuum noises which can also make it onto the cutting groove.

 

Also  a revelation for me was his method of setting up VTA using a microscope on the needle to determine the correct 92 degree angle instead of using the arm as a reference in which he also showed examples of high end carts where the diamond was attached at incorrect angles onto the cantilever. Cannot remember the exact math but think it was something like every degree the diamond is incorrectly angled necessitated in a18mm adjustment at the arms pivot point!

 

Also went into detail with azimuth adjustment (use a oscilloscope or multimeter) and how adjusting this also affects VTA.

 

Would have been nice if a handout was available at the end as there was a lot to take in but that aside it was definitely the show highlight for me (Krispy's funky SOTA table coming a close second)

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Thanks for the feedback Tubularbells, sounds like it was an interesting seminar with the development of the caliburn he has probably forgotten more technical knowledge than most designers have learnt. I take it it wasn't recorded which sounds like it would have been a good reference even for people who attended. Interesting comment about azimuth i wasn't aware that it changes with VTA/SRA adjustment?

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TB, you sure you aren't getting mixed up with VTA affecting VTF? Azimuth is a completely different plane of motion, don't see how it can affect anything else.... ?

 

Did anyone attend it over the weekend?

Edited by tal

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Could be wrong but I'm sure that's what he said. To be honest I'm also puzzled by this as I also cannot see any correlation between the two. (kicking myself for not confirming with him later)

Just remember him saying it was a juggling act between these two settings. Hopefully others who attended can confirm.

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i think it was VTA will effect Azimuth, so you would adjust azimuth by test record and voltmeter or oscilloscope  only after precise VTA.

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I attended his presentation on Friday and it was very informative especially the info around the cutting lathe. He went into relative detail about the lathes limitations where specific signals were injected into the cutting head to counter the heads resonant frequency through to the bearing and vacuum noises which can also make it onto the cutting groove.

I was there for about 2 minutes and that was the bit I heard. Just lucky I guess!

 

Also  a revelation for me was his method of setting up VTA using a microscope on the needle to determine the correct 92 degree angle instead of using the arm as a reference in which he also showed examples of high end carts where the diamond was attached at incorrect angles onto the cantilever. Cannot remember the exact math but think it was something like every degree the diamond is incorrectly angled necessitated in a18mm adjustment at the arms pivot point!

by quick calc I reckon it might have been about 4mm

 

Also went into detail with azimuth adjustment (use a oscilloscope or multimeter) and how adjusting this also affects VTA.

After changing azimuth, the measured VTA would change by a tiny amount, but maybe the 'best sounding' VTA setting changes a bit more?

 

Would have been nice if a handout was available at the end as there was a lot to take in but that aside it was definitely the show highlight for me

After he bent my ear off in his room, preventing the playing of music on exotic gear I will never see again, I wasn't going to sit for a second serve!

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