Yeas ddk is known as the kindest most patient contributor to WBF
As long as you don't piss him of
The importance of VTA, SRA and Azimuth - pics
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As long as you don't piss him of
Yeas ddk is known as the kindest most patient contributor to WBF
As for the WallySRA, I’ve lost interest in it. It is a jig for the cartridge to be mounted into for microscopic analysis. I came to the conclusion that the added benefits it provides don’t offer enough value given what I’d have to charge for it to make it worthwhile. I may change my mind later but other developments have my interest now.
I don’t use a USB scope for static SRA measurements but I’ve learned a good deal from working with compound objectives and much of the tips and tricks to make it easier and more accurate are usable with USB scopes. I’ll be sharing these soon
VTA change also changes VTF but that generally happens on static balance tonearms, not on dynamic balance ones.
As far as Azimuth, I've done the eye ball thing, CD thing and by ear. I was using the TruRTA Analyzer playing a 1KHz tone off AP Test LP, I was never really satisfied with the testing and results, I knew I was close but could do better. So I bought a Foz Meter and that just made the process so simple and quick, super easy. I always make sure I have a fresh 9V battery as well calibrate with the Foz with test tones from a CD.
As someone mentioned the tick marks on the analog meter mean nothing, I too thought originally they were dB but quickly realized no. Your just trying to adjust for a balanced output L and R, the needle in the same spot for each channel signal, using L and R tracks. The the 2-channel mono signal you want a 0 reading. But I wanted to see how to minimize the output in the non signal channel (1KHz tone in L channel only and vice versa). So I tried using a DVM, man that is just too hard trying to read the digital readout, jumps around too much. The Foz has filters to keep signal in check.
So what I do (someone tell me if this is wrong...), I play track 2 and 3 of AP Test LP and disconnect the interconnect that has the signal so the Foz is only giving me a reading of what's in the non signal channel, cross talk/bleed. Then other channel and I adjust for same reading as close to zero as possible. The challenge was to get these both to 0 as well same channel readings when adjusting for highest reading.....I am spot on with L to R readings and the cross talk/bleed to less than a half space, one channel is at about 2 ticks, the other is like 1.75 ticks.
Fill in all the normal audio adjectives we use when things are as lined up as possible, and you play a record.......
As someone mentioned the tick marks on the analog meter mean nothing, I too thought originally they were dB but quickly realized no. Your just trying to adjust for a balanced output L and R, the needle in the same spot for each channel signal, using L and R tracks. The the 2-channel mono signal you want a 0 reading. But I wanted to see how to minimize the output in the non signal channel (1KHz tone in L channel only and vice versa). So I tried using a DVM, man that is just too hard trying to read the digital readout, jumps around too much. The Foz has filters to keep signal in check.
So what I do (someone tell me if this is wrong...), I play track 2 and 3 of AP Test LP and disconnect the interconnect that has the signal so the Foz is only giving me a reading of what's in the non signal channel, cross talk/bleed. Then other channel and I adjust for same reading as close to zero as possible. The challenge was to get these both to 0 as well same channel readings when adjusting for highest reading.....I am spot on with L to R readings and the cross talk/bleed to less than a half space, one channel is at about 2 ticks, the other is like 1.75 ticks.
Fill in all the normal audio adjectives we use when things are as lined up as possible, and you play a record.......
That’s wrong (sorry) cause Fozgometer is doing it for you in normal operation. the problem with fozgometer is that it can mislead you if other alignments are not perfect. it tries to compensate improper channel balance due to other alignments such as vta, zenith etc. additionally, achieving a proper channel balance does not mean you have correct azimuth.
I recommend you to use a good usb microscope and try to align stylus perpendicular in the groove. If you can achieve perfect channel balance at the same time that’s great but if not stick with the stylus being perpendicular in the groove and check zenith, vta, antiskating etc. I believe that full frequency response achieved by a properly set stylus in the groove is more important than channel balance or phase. Furthermore consider getting a software based aligning tool for better results.
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Fozgometer uses a multivariate environment to lock in the ideal setting for a single variable - azimuth. This is FAR from ideal but it is the only reliable method I know of to measure azimuth since azimuth isn't only a function of the alignment of the stylus on the cantilever but also the alignment of the coils on the cantilever. This is why the visual alignment method for azimuth is not a reliable way to tell the whole story of ideal azimuth alignment.
All worthwhile azimuth measurements methods use a multivariate environment of the stylus scraping through the groove and throwing off an electrical signal. But, just like all software methods of measurement, it is fraught with problems. I am NOT a fan of multivariate environment testing (such as the software solutions) since they cannot detect a stylus mount flaw and achieving perfect alignment on all parameters is never a certainty since no parameter setting can be determined in isolation.
However, if you know the ideal angle of ONE of your parameters independent of the the influence of other parameters, then it acts as a sort of Rosetta Stone. Case in point: yesterday I analyzed another very high end cartridge ($11,000 retail) that had nearly a 5 degree zenith error. When I measured the azimuth for even crosstalk with the cantilever aligned normally at the null points (prior to zenith correction) I was getting 26.1dB/26.2dB crosstalk. Musical performance was decent. After correcting for the nearly 5 degree zenith error, the musical results were fantastic but the azimuth results had changed to 36.9dB/25.5dB. So, I refined azimuth again and landed at 29.2dB/30.3dB.
There is no way I could have arrived at this perfect alignment had I not known with certainty where at least ONE of my targets was and aligned for it. Univariate tests are absolutely necessary (e.g., microscopy for dynamic SRA) in order to have a touchstone when you have no other choice than to use a multivariate test (azimuth)
Catcher10, forget about "aligning" for channel balance. That can't be done mechanically. When you use the Fozgometer, you are aligning for "crosstalk balance" not channel balance. I suggest you keep working at it.
I'll have an at-home solution for zenith error measurement this year. I simply can't believe what I am seeing on the bench and it is not acceptable to me that one needs an industrial microscope to measure it reliably. There is a way, but not without the solid inclusion of univariate test methods.
Thanks J.R. for this post and feedback. Maybe it is semantics but I suppose I do mean crosstalk balance vs channel balance. I've always looked at these adjustments as "the best possible scenario" and so far the Foz meter gets me there quickly and easily. I don't care for the software adjustment offerings, they just don't seem accurate enough for me but that could just be my ignorance, but a bubble level does not seem accurate.....
As I said I have done the visual thing with scope and set the stylus as perpendicular to record surface as possible but one does not know how the rest of the generator was built, so you could be wayyy off and not realize it. And again after using the Foz the sonic difference was pretty overwhelming, the things we look for is what I experience.
Using the Foz and adjusting for crosstalk balance seems to have given me a better performance than simply adjusting for my L and R signal to be the same. If I do that then check how close I am to zero it's within 2 clicks, but if I adjust to get to zero then that is where I get improved dynamics, soundstage and especially resolution. I think for my Delos its as good as I can get it what I need to get better at is SRA, the krappy USB scope I have does not get close enough image so I can measure the angle. So I simply set the cart parallel to surface due to the Lyra New Angle design, but still would like to know that SRA is where it should be.
Looking forward to your in-home solution!
Thanks again
José
Ask and you shall receive! ;-) Are you not planning on joining our SRA webinar tomorrow? See analogplanet.com for the news.
Did not know about that....dang it!! 11am PST I'm busy with HS coaching.......maybe it will be recorded??
So here is a thought- If the physical alignment aspects are all dialed in should there be a phono standard for equalizing ( adjusting ) levels at the preamp for a certain frequency or frequencies ( by means of test record ) for calibration purposes? Since perfection is not to be found...
My old Neumann VMS70 rack had some such adustment at the playback module; this is the only time I have seen such.
My old Neumann VMS70 rack had some such adustment at the playback module; this is the only time I have seen such.
I was under the impression that equalization should occur before measuring azimuth - which does not invalidate your suggestion. Maybe it's a chicken and egg thing where one equalizes then sets azimuth then repeat until achieving the smallest difference between channels.
I raised this question in my thread Calling Adjust+ Experts ...: how far from perpendicular are you willing to go with your own stylus and records? How many degrees?
If I am more than 3 degrees off on any of the three parameters (SRA, zenith, azimuth), I am beyond the tolerance parameters for any stylus/cantilever assembly manufacturer that I know of. I don't know them all, but I cannot imagine that more than that would be tolerated by the cartridge manufacturer. HOWEVER, your CARTRIDGE can have an ideal azimuth angle of 4.5 degrees and still be within tolerance. How? Say you have an Ogura assembly on your cartridge that has a 3 degree STYLUS azimuth error and the COILS have a 1.5 degree error and those are both the limits of tolerance and the error for both was in the same direction, you could end up with a 4.5 degree ideal azimuth angle.
Thanks for your follow-up. Three degrees is a lot.
Can you measure coil error separately from azimuth error?
I suppose I could by first analyzing the azimuth angle of the stylus via some very high end microscopy and then taking the difference between that angle and the angle the cartridge is at once it is at its ideal azimuth angle.
Watched the podcast recording......Very well done, one of the better ones for sure!! I need to really spend time with the USB scope I have, it's an AmScope 20x-800x and yea very suspect on the specs. But it is so wonky to operate, I need the stand/holder you have that should help a lot to stabilize the image. All the suggestions you gave were excellent, especially taking dynamic images and measurements, never thought about that.
Appreciate the time in doing that!
Cheers
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