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| Author: | Pelliott321 [ March 28th, 2016, 8:22 pm ] |
| Post subject: | Re: Cartridge adjustment |
I read the article and did not see anything about Vta, just antiskatin, resonance, and others |
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| Author: | SoundMods [ March 29th, 2016, 9:56 am ] | ||
| Post subject: | Re: Cartridge adjustment | ||
The attached White Paper is capable of inducing a major head-ache after reading it, but it can shed some light on the recording end of the LP to help with the playback adjustments.  After all is said and done it still comes down to adjusting for the best sound in your particular system.
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| Author: | tomp [ March 29th, 2016, 11:20 am ] | ||
| Post subject: | Re: Cartridge adjustment | ||
Good paper. The interesting thing about VTA error is how it is frequency dependent which makes sense if you think about the grooves. As the frequency goes up the radius of the groove goes down to the point where a stylus even of the most correct shape vs the cutter has difficulty following it. If you then have the angle of the vertical edge of the stylus at an angle different from the cutter the stylus cannot follow the groove properly and will tend to run across the groove. It will also induce a vertical modulation which is mentioned in the paper that will further distort the signal. It just goes to show what a miracle it is that a properly set up system can sound so good. Tom
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| Author: | SoundMods [ March 29th, 2016, 11:51 am ] |
| Post subject: | Re: Cartridge adjustment |
A miracle is a gross understatement. I've put a lot of DIY work into CD playback and am quite proud of the results I am getting. Yet -- the same level of attention to LP playback results in playback quality that the CD gets close in some instances but no where near the sound quality of a superb well-recorded and pressed LP. Even some old "vintage" LPs can be exceptional -- I expect that some of those 40 to 50 year-ago efforts were not even appreciated given the playback equipment available back then. I have many gee-wiz moments with LPs, but few with CD. As a note on cartridge alignment -- stylus rake angle is a starting point, but all bets are off if the cartridge manufacturer creates a cartridge with the tracking angle (the angular path of the stylus/cantilever) not matching cutter standards. You read cartridge reviews where they go through the measurement drill and the tracking angle range seems to run from the "God given" 15-degrees to as much as 28-degrees. So much for standards. |
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| Author: | Pelliott321 [ March 29th, 2016, 11:59 am ] |
| Post subject: | Re: Cartridge adjustment |
Yes its is amazing that a boulder dragging through a trashed filled alley makes music at all. I also know that standards at the cutting stage do not exit, as well as the thickness of the LP, so all this care of setting up is a bit like chasing a chicken around the yard. I am just after a system to get close. Using set up protractors still seem a bit loose to me. Instruction say to line up so cartridge body is parallel to lines but they really mean cantilever which is hard to see. This is why I am trying to use the digital microscope. My Alphason arm does not have VTA calibration, just a support tube in a mounting collar with set screws. Before I move anything I need to figure out a measuring system, that is repeatable. I am very jealous of arms that allow adjustment on the fly, but just as curious if such a system is rigid. Peter Riggle does not think its necessary. His VTA adjustment mod is just one threaded tube inside another with no locking. |
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| Author: | SoundMods [ March 29th, 2016, 12:11 pm ] |
| Post subject: | Re: Cartridge adjustment |
Probably more trash with some people. I cringe when I see someone handle a LP with their meat-hooks all over the groove area. Or see an LP at an audiphile's house with enough grime on the LP where it sounds the cereal Rice Krispies. UGH!!! Anyhow -- the protractors are fine using the front edge of cartridge body as a reference. Japanese turntable manufacturers as well as other provide either a template or specs for overhang adjustment. As far as SRA and tracking angle is concerned -- if your arm does not allow enough vertical height adjustment you can manufacture a shim that fits between the cartridge and the head shell to tilt the mounted cartridge to an acceptable angle. I've done that with the expected success. Some cartridges even come with "tools" like that. AKG comes to mind. Or -- you can manufacture an adapter to raise the arm for a more effective arm height. I did that with my previous TT with success. |
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| Author: | Pelliott321 [ March 29th, 2016, 12:53 pm ] |
| Post subject: | Re: Cartridge adjustment |
I did not say my arm does not have an adjustment just that it is troublesome. And gee, I do have enough grey matter left to figure out that shims will work. I did witness with eyes and ears the other day of the advantage of ultrasonic cleaning and will be building one soon. |
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| Author: | tomp [ March 29th, 2016, 2:49 pm ] |
| Post subject: | Re: Cartridge adjustment |
Also rember that if you are adjusting the tracking angle by moving the arm up or dows you are also changing the posiition of the stylus fore and aft in reference to the optimum tangent point. If the arm were totally parallel to the record surface that change would be minimal. As the angle of the arm gets greater to the record surface the changes get larger faster. I'm not sure but it is probably a sine function. The protractor or set up guide will help with that as you can slide the cartridge back an forth to reposition the stylus. The ideal way to adjust tracking angle would be to have a headshell that could rotate the cartridge with the center of rotation around the stylus point when under tracing force load. I seem to remember an arm that had something close to but not exactly that. Tom |
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| Author: | SoundMods [ March 29th, 2016, 3:30 pm ] |
| Post subject: | Re: Cartridge adjustment |
I get the troublesome adjustment -- I have the same issue here -- it is a royal pain-in-the-ass. I threw the shim idea out there presuming that you (Paul) didn't consider it.  I have an ultrasonic record cleaner that is worth every penny I paid for it. The guy that built and sold it used readily available equipment to complete it. The only custom part was the mounting for the motor that he fabricated out of HDPE. You (Paul) could easily duplicate the effort with wood.  Unless an LP has groove damage from misuse, the ultrasonic cleaner has provided me with vintage records that play like new. Putting math and theories aside, it still comes down to sound quality and making adjustments based on "ear testing" still gets you where you want to be. 
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| Author: | Roscoe Primrose [ March 30th, 2016, 9:03 am ] |
| Post subject: | Re: Cartridge adjustment |
tomp wrote: Also rember that if you are adjusting the tracking angle by moving the arm up or dows you are also changing the posiition of the stylus fore and aft in reference to the optimum tangent point. If the arm were totally parallel to the record surface that change would be minimal. Tom The change is going to be too small to measure with any stylus protractor I've ever seen. If you start with a standard 9" arm, which has a typical stylus-to-pivot distance of 224mm and is parallel to the record surface, moving the pivot point up or down 5mm (which is a HUGE amount when adjusting VTA) you're only moving the stylus back .056mm. Good luck measuring that, or adjusting your cartridge in the headshell by such a small amount. Of course, if you're using a longer arm the differences would be even smaller. Roscoe |
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