Doug,
What method do you use to adjust azimuth in measurable and repeatable increments of less than 1 degree? I understand how VTA and VTF can be adjusted to that kind of resolution, but azimuth has me stumped. Please describe your SOP, and how it might be applicable to all tonearms or whether it's something specialized to your Triplanar. Thanks!
David |
James,
The filter is not needed if you have an oscilloscope to measure the channels. You will need the filter if you use a DMM to take the measurements. I don't know exactly how steep the slopes need to be, but 12 dB should be ok as a start. If you search the web there are filter calculators to help with the component values. If you go this route just find a bread board and put the filter together that way. Use the cheapest components you can find. |
Very interesting.
Dan_ed, I have always wondered how to get around the surface noise issue, seems like surface noise alone adds quite a bit of 'variability' to the signal from what I have seen. A bandpass filter makes perfect sense. But I don't know how I would implement one, I will have to research that a little more.
Doug, I would agree on ultimately using your ears to make calibration adjustments. I have an over hang tool that came with my Technics turntable, I find the tool to adjust the needle relative to the over hang mark will put the cartridge in in the neighborhood of where it should be, but further adjustments by ear is far more precise.
Thank you both,
best,
James |
James1969,
When I adjusted azimuth with this method I used the Wally Analog Shop, same as Jtimothya. It works exactly as he described and you can DIY as he also described, subject to Dan_Ed's provision that you use a narrow bandpass filter centered on the frequency of the test tone. Without that, surface noise makes readings highly variable and difficult to interpret.
I actually haven't bothered with the Analag Shop for at least a couple of years. As the resolution of our system grew we learned to adjust azimuth by listening, just as accurately, faster and while playing music rather than test tones. Besides, our current cartridge, when properly azimuth-ed, produces crosstalk below the resolution of my multimeter. Using Wally's chart it's somewhere below 0.3db, which makes the whole rigamarole ineffective without investing in more sensitive equipment. It's easier to just play music and fiddle!
The thing to listen for is the tightest possible sonic images (from L to R). The narrower and better focused an instrument or vocalist sounds, the closer you are to minimal crosstalk. Intruments and vocalists with pure tones in the higher registers are best. Our hearing system is most sensitive to directional/spatial clues at higher frequencies.
BTW, I wouldn't say the measuring method isn't worth trying. You'll learn something, including how remarkably tiny adjustments to azimuth can have a measurable and audible influence. From your baseline starting position (which probably should be "stylus appears vertical while playing in the groove", not "headshell appears horizontal") changes of less than 1 degree will make a difference. Go very gently with this adjustment.
Best,
Doug
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Be sure to read on down that thread on the importance of using a bandpass filter at 1kHz, or you won't get the desired results. |
Tim, excellent thread, thank you. |
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I have been playing with this PureVinyl software in combination with using the HiFi-News test record. There is a real time Input Balance measurement that gives you a +/- 0.00 measurement. So this would be a differential offset of channel balance.
I would guess that to measure crosstalk, one would have to find a test track for left and a test track for right channels to see the bleed over onto the opposite channel? The idea is to have minimal bleed over into the disabled channel of the test track? |
James1969, as Shure once had a record and meter that allowed you to adjust the channel outputs by changing Azimuth, so Denon once had a meter that allowed you to minimize crosstalk. I think I remember that you could also get a Denon product that reduced crosstalk. I have had and sold all of these and rely on my ears. |
Stringreen, thank you for the tip on the search, I found what I was looking for in this thread:
http://www.audioasylum.com/audio/vinyl/messages/74644.html
Dougdeacon, how do you measure crosstalk? |
Azimuth alignment is what I meant to say. I have been adjusting the azimuth adjustment on my headshell seeing the impact on channel balance using the various test tracks on the Hi-FiNews Analogue Test LP. Sorry for my confusion. |
No one I know uses channel balance to adjust cartridge alignment.
"Channel balance" means the relative strength of one channel vs. the other. If that's what you meant, it's unclear to me that measuring channel balance would be useful for adjusting any cartridge setup parameter.
"Cartridge alignment" usually means the combination of a cartridge's position along the headshell slots ("Overhang") and its angle in the headshell slots when viewed from above ("Zenith Angle"). Neither of these parameters affects channel balance in any meaningful or useable way.
Gross changes in Antiskating can sometimes affect channel balance, but measuring channel balance would be an ineffective method for adjusting that IME.
Azimuth angle (the angle the stylus makes relative to vertical when viewed from the front) effects inter-channel crosstalk. Many people, including me, have measured that to adjust azimuth and it's an effective method. Azimuth may also effect channel balance, but using that measurement to adjust azimuth would be far less precise than measuring crosstalk.
The other major cartridge setup parameters, VTF and VTA/SRA have no effect on channel balance that I'm aware of.
Doug |
Check the posts regarding Azimuth adjustment. Use DVOM |
