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Dear Bruce: The SRA monitoring procedure is as Mofimadness stated.
However, as I recently wrote in Stereophile, the construction of every tonearm that I am aware of (with the sole exception of the Eminent Technology linear trackers) guarantees that altering SRA will simultaneously cause the effective length to change, along with the tracking force.
To make sure that any SRA-induced audible changes are truly attributable to SRA rather than sundry alignment shifts that came along for the ride, you must recheck the overhang and tracking force and "put them back" to what they were prior to the VTA change.
At the end of the day, you may ponder about the real value of "VTA on-the-fly" mechanisms (grin).
kind regards, jonathan |
Bruce, you will note that in the first photo of the analogplanet link that Mofi posted, Mikey is also using the digital microscope to set up a Lyra Kleos cartridge, just like yours.
Great links Mofi!
Cheers,
John |
VTA depends on the cantilever angle, angle of stylus A_N_D what kind of Diamond is used. The side walls have different cuts (and more...) and they track the information. So it is logical that every change in that "angle" will give you different results. some record collectors say, you simply have to dial it in, until it "settles". You can hear it. Another chapter is the cutting angle from mastering...
The VTA adjustment is necessary when you listen to older records (until the end of 60's), when you use an old Mercury/London/RCA ... you can hear how the soundstage gets wider and deeper.
The SRA explanation is another - different - chapter and also has influence to VTA adjustment. But the VTA adjustment is only the way to get the angle the older records were cut for proper reproduction....
What you have done to find a good result is right, but to repeat it again, a VTA at a "given angle" is wrong, the given angle is for SRA and a statement from M. Fremer which sounds important in discussions but is totally overrated in reality.
It is ok when someone uses an Arm which can't be adjusted in the height, when he also uses an arm which is perfectly aligned from arm board to record surface distance (level) and when he listens only to records which were done after 1980 and when the cartridge height overall fits also for level adjustment with the given cantilever length, angle...and there are some more...it may be ok when someone uses a table AND a matched Arm from a Manufacturer ... anyway, forget it and do it the way you did before |
Thanks guys, esepcially for the terminology lesson. I always thought that VTA and SRA are flip sides of the same adjustment. That is, VTA and SRA change as a result of raising or lowering the tonearm.
Jonathan, I can visualize that raising the tonearm geometrically changes the effective length of the tomearm. And, the VTF force vector will correlatively change as well. However, I find that these variables change only slightly. Maybe it's because my tonearm is 10.5 inches long.
In my earlier days of vinyl OCD, I actually remeasured alignment, VTF and even azimuth after changing VTA/SRA. The changes were very, very slight. Too much OCD for me now to mess with it. But ... I am able to detect changes in the acoustic presentation when I raise/lower the tonearm.
So, as I mentioned above, I start out by setting the arm to be horizontal/level based on an eyeball look-see. Then I raise/lower the arm until it subjectively sounds best to me.
I'll check out the links provided. Thanks for that information.
That leaves me with a question or two though, perhaps best addressed by Jonathan Carr. Could my methodology damage my "beloved" Kleos cartridge/stylus or my LPs? Relatedly, is my "eyeball" method resulting in degraded sonics, qualitatively speaking? Is it worth investing in a USB digital microspope?
Thanks again guys!!
Bruce
P.S. -- Jonathan, would you kindly repeat your advice about sending my Kleos cartridge back to Lyra for an inspection and adjustment (if needed). I'd like to have it checked to ensure that it is operating within spec. |
J Carr's comments are spot on. If you look at the original paper Michael Fremer cites re: SRA, it is not an exact measurement; rather it indicates a range. You are correct in assuming that it is difficult to measure SRA with precision and accuracy. Dave Slage has pointed out how small parallax effects can significantly influence SRA measurements and reproducibility. Fortunately, we are not listening to a measurement. By all means, if measuring gives you a degree of confidence that you are in the ballpark of optimal set up; get out your computer and USB microscope and measure away. Ultimately, your ear will be the best guide for SRA/VTA parameters. And don't forget to recheck all other set up parameters once you've got SRA/VTA spot on. Yes, it's an iterative process that may require mutliple listening sessions. |
Dear Bruce: I've used 10.5 inch (and longer) tonearms, and my experience was that the VTF and overhang errors introduced by SRA changes were significant enough that correcting the VTF and overhang did alter the sound. The real PITA is that you need to repeat the cycle a few times in a series of gradually diminishing spirals before you can be reasonably confident that you have accounted for all variables, but that can't be avoided.
If you go to Stereophile's website, you will be able to find Mikey's review of the Etna. In the Manufacturer's Comments, I have added a wee bit about SRA in general, which I think you will find worth reading.
Ultimately you listen with your ears rather than your eyes. The visual method is simply intended to get you into putting range quickly, but you will still need to do the final tweaking by trial and error and ear.
Regarding possible cartridge damage... There was one dealer who thought that he wasn't able to lower the back of his Kleos sufficiently, so he ripped off the protective washi cover to give himself extra room. Please don't ape this (smile).
I recommend that you get in touch with Alasdair Patrick at Audioquest, and have him tell you when and where to send in the Kleos. Please stick a memo on the outside of the box to the effect that you don't think that there is anything outright wrong with the cartridge, but in consideration of how long you have used it (provide purchase date, please) that you would like to have it inspected for wear, suspension ride height and alignment.
At the time that you send the Kleos to Audioquest, you could also email me the cartridge serial number and perhaps a slightly more fleshed-out version of the memo that you attached to the outside of the box.
kind regards, jonathan |
Thanks J Carr!! :)
I will be sad until I get my Kleos back. :( :( |
Bif,
I just got my Delos back from Lyra in Japan and here is how
you do it.
Send an email to apatrick@audioquest.com and tell him why
you need to send your Kleos in. He will email you a RMA
form that you fill out and email back to him. You will get
a completed RMA form in pdf to print out and send into
Audioquest with your cartridge. All the return info will be
included with the RMA form.
It took less than two hours from the time I started this to
get all the stuff I needed to send it back to Audioquest.
Actually I had the cartridge in the mail,(via Priority Mail)
in less than two hours. The only cost incurred to me was
the shipping from me to Audioquest, which was all of $5.00.
I got my Delos back six weeks to the day I sent it in. It
had a collapsed suspension and Lyra fixed it, cleaned and
polished the cartridge, replaced the Washi paper with a new
one and even supplied new mounting hardware...all at NO
COST!
Alasdair was PHENOMENAL to work with. He really took care
of me and I have the highest regards for both
Alasdair/Audioquest and Lyra. Two absolutely WONDERFUL
companies!!!
I need to also give a big THANK YOU to Jonathan. He
answered several questions for me and always had the time
and guidance to give me. We really couldn't ask for better
people in the high-end business to deal with. |
OK, I've read Michael Fremer's comments regarding SRA and VTA and am still confused about the difference. Perhaps someone here can put this in perspective for me (and maybe a bunch of other folks)!
As I understand it, you change the VTA by lowering or raising the pivot point of the tonearm, which also changes the SRA. I had always thought of it that way since making those changes alters the angle at which the stylus contacts the record surface, hence trying to immitate the angle at which the record was cut. So, what's the difference between the two???
VTA/SRA can also be changed by lengthening/shortening the effective tonearm length, also called overhang I believe, but it still affects both of these parameters so, again, what's the difference?
Raising or lowering tracking force also changes the angle in both cases. I'm missing something here and would sure like to know what? Anyone else confused by this? |
IMHO there is nothing wrong with the OP's procedure.
If you can't hear the difference it is not important, if you can hear, then you have done the alignment. The USB microscope may give you a closer starting point, but that all folks! |
In reality, everything affects everything. You aren't done when you change the height of the arm..you must recheck how the raising/lowering affects the downward pressure. Once that is adjusted, you must make sure the stylus still sits in the absolute correct spot of the alignment gauge,...and then understand that all of that has to be checked and adjusted again, and then again, until gradually you are satisfied and can walk away (for a long drink and well deserved rest). |
Excellent post by Jcarr. As usual.:)
"However, as I recently wrote in Stereophile, the
construction of every tonearm that I am aware of (with the
sole exception of the Eminent Technology linear trackers)
guarantees that altering SRA will simultaneously cause the
effective length to change, along with the tracking force.
To make sure that any SRA-induced audible changes are truly
attributable to SRA rather than sundry alignment shifts that
came along for the ride, you must recheck the overhang and
tracking force and "put them back" to what they
were prior to the VTA change.
At the end of the day, you may ponder about the real value
of "VTA on-the-fly" mechanisms (grin).
kind regards, jonathan"
I would just like to add that IMO overhang should be the
last adjustment done after changing the other parameters. We
could argue the order but I think it should be SRA first,
then VTF, and finally Overhang last.
Then there is Azimuth. If you have a linear tracker or a
pivoted tonearm that adjusts Azimuth in the same plane as
the offset angle then adjusting Azimuth should not effect
the other settings much at all. On the other hand most
pivoted arms adjust azimuth at the back of the arm.This
adjustment is not in the same plane as the offset angle.
When this is the case, changing azimuth will effect all of
the other settings (VTF,SRA, and overhang). In this case I
would do it in this order. SRA, Azimuth, VTF, and then
Overhang.
As said above, this needs to be done multiple
times by ear to dial it in.
Sean |
I might add my tuppence here.
Firstly, Adjusting SRA/VTA makes a huge difference to tracking force on most arms. What you hear is the alteration in tracking force predominantly, unless you reset this after each adjustment....which defeats the purpose of VTA on the fly. Just try it out.
Second point is that to make a substantial difference to SRA you will need to change the base of the tonearm some 10mm to achieve 1 degree change in SRA (depending on the length of the tone arm, 15mm on a 12 inch).
My final point is I took a lot of brilliant photos of my stylus on the record, and measured the SRA repeatedly. I did it so often, I damaged the suspension, and required a cartridge rebuild.....and never managed to achieve 92 degrees. So now I set tone arm level, play around a bit from there, until it sounds right, compensating for tracking force with each change, finally I reset overhang, and alignment.
As illustration, just putting my record weight on my ClearAudio CMB, increases the tracking force by 0.02 grams (it compresses the magnetic bearing and lowers the whole platter), so I can see how a thinner record will see a greater tracking force than a thicker record, the change in SRA will be much < 0.1 degrees. Since not all records are cut at precisely 92 degrees, I'm not sure that this is the holy grail.
I'm sure the debate will go on but after much trouble, I have concluded that the changes in tone arm base height relative to the change in SRA are too great to make a meaningful difference in SRA, but what they do do very effectively is change the tracking force. The change in overhang is tiny, just check geometry with different systems Baerwald/Lofgren/Stephenson, and see the differences are not that small, which to me means a range is acceptable?
I must conclude that I am not an "expert" by a long way, but have had a painful and costly experience with this question, and read just about everything I could lay my hands on, and then did some basic trig on the angles. |
I thought I read that M. Fremer wrote that with a 9" arm, a 4mm change in height amounts to a 1 degree SRA change. I have a 12" arm and adjust my SRA for different LPs. I move my arm up and down in a 3mm range which amounts to about a 1/2 degree SRA difference. That sounds tiny, but it is audible and worth the effort to me. I don't then also adjust VTF and overhang, though I know they are effected.
I mark my LPs with the best setting height for reference and this does not correspond to the varying record thicknesses. For example, I have lots of LPs that are say 160g and they cover the full 3mm range of best VTA. Same for my 180g LPs. |
Dinster, Baerwald is the best compromise for the records I play. I like to stay as close to that as possible. YMMV.
It is not an issue on my Schroder LT. With this linear tracker I can easily dial alignment in by ear. |
Apologies Peterayer, you are correct. I redid the calculations and 5.3mm change in base height on a 12 inch arm (304mm), changes the SRA by 1 degree. Sine theta = vertical change in height (opposite)/length of tone arm (hypotenuse). This adjustment will decrease the overhang by 0.046mm, and change the tracking force a variable amount depending on where the centre of gravity of the tone arm is. My SRA was consistently 95-96 degrees, and I suspect the 15mm came from me thinking that is what I would have to do to get the SRA correct....sink the base in to the plinth!! |
Dinster, another way to change SRA is by placing a shim between the cartridge and headshell. Placing the shim behind the cartridge screws will have the same effect as lowering the back of the arm. Of course if you have to lower the back of the cartridge so much that it drags on the record then there is something very wrong.
Using a shim is not an ideal solution but it will at least let you hear if achieving 92 degrees with that cart is a good thing or not.
I find it hard to believe your calculations for overhang change are accurate. They don't jive with my experiments. Could your decimal placement be off? |
I use a Mint LP arc-type protractor and looked at the alignment with slightly different SRA angles. The stylus tip basically shifted from the center of the inscribed arc line to the outer or inner edge of that line, and it is a very thin line. I can not really hear a difference in that small a change to overhang. |
Peter, that sounds about right with small changes in SRA. With a 1 degree change in SRA the difference will be large enough to worry about. |
Folks, I make this post with a smile and a frown. Based on the good advice from Jonathan Carr and a few others, I've made arrangements to send my Kleos back to Lyra for a check up. The smile is that I am taking the advice of people who know what they're talking about. This way I'll know that my Kleos is in tip-top working order when it comes back in 6 to 8 weeks.
And that's why I am sad. :( I won't be able to use my Kleos for 6 to 8 weeks.
IMHO, this is one super-duper cartridge. I still have my S-S VPI Zephyr, but the Kleos is in another league.
What else can I say? :( I suppose, if this is the worst thing that ever happens to me, thank G-d.
Bruce |
I am confused which SRA angle I should actually. In the original article and subsequent articles measuring SRA with a microscope by Michael Fremer the angle is measured between the horizontal record and and line which runs theough the middle of the stylus. On the other hand, in a recent article in TAS on tt setup by Andre Jennings and other articles/posts in the internet the SRA is measured as the angle between the record surface and the backside of the cartridge. Depending on the cartridge I would estimate thag the difference between the two ways of measuring are approx. 7-10 degrees. Am I misunderstanding something or is the correct angle to measure depending on the type of cartridge (in my case Dyna 17D3)? |
It depends on the stylus type. I think that the Ortofon Replicant stylus is meant to be measured along the rear edge of the stylus while most other stylus shapes are meant to be measured along the center shank axis. MF discusses this somewhere. You may find it in his Ortofon A90 review. |
Gemini05,
Expanding on Peter's response, if you're obsessive enough to visually measure SRA, what needs to be measured is the vertical contact line of the stylus. That's what actually interfaces with the modulated grooves of an LP.
As Peter implied, whether this line falls at the front or back face of the stylus or somewhere in between depends on the stylus shape.
FYI, on some styli the contact line is easy to see, on others it's difficult or impossible.
Measuring anything other than the stylus's vertical contact line would produce a number only randomly related to its playback characteristics, not a measurement in any meaningful sense.
P.S. For completeness it should be noted that conical (aka, spherical) styli have no vertical contact lines, just two contact points. The lack of any vertical dimension in their contact surfaces makes SRA mathematically meaningless for conical styli. This explains why SRA changes with such styli are inaudible, which confirms the concept stated in my first paragraph by negative example.
***
So much for theory. As others have stated, visual measurement of SRA is largely a waste of time. The most it can do is put you in the ballpark prior to final adjustment by listening. There are faster, easier and less expensive ways to do that than visual SRA measurement.
You can get in the ballpark in about 30 seconds with no measuring tools, magnification or special lighting. Just eyeball to make the cartridge top surface or (second best) the tonearm visually level to the record surface. That's almost always close enough. Fine tune by listening.
In an unfamiliar system with an unfamiliar tonearm and cartridge, I can optimize SRA for a particular LP in 2-3 minutes. In my own system it's even less, since the roughing in by eye has already been done. USB microscope geeks are still hunting for their tools while I'm listening to music, with SRA optimized at least as well as theirs will ever be. ;-)
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Ditto what Doug said. Life is short. |
Thank you for your quick comments, which I read with some relief as I was not really looking forward to buying a microscope + stand and spending a day or, as I am not really handy with computer programs and all this, several days learning to handle it. \
I think an underlying reason for my question may have been that I am not quite sure what to strive for in my system, i.e. what sound could be achieved in my room with my gear when everything is set up just right and thus form the reference. I get a lot of compliments for the music from friends and other visitors but am sure that considerable improvements could be achieved by someone more proficient than I am.
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Thanks Doug.
As usual, Doug explains it as it is, or as it should be. The key is to know what to listen for. Doug explained that in another VTA thread.
I've got a USB microscope, but I use it only to take close up photos of the cartridge to confirm things I can't see quite as well with my naked eyes. eg. stylus shape, cantilever alignment, etc. It is a fun tool, but I no longer used it for SRA angles.
For a quick guide, I use a 10X loupe to confirm that the stylus is just past vertical, which is close enough to get started. Then, from there, I adjust by listening. |
"I need to also give a big THANK YOU to Jonathan. He
answered several questions for me and always had the time
and guidance to give me. We really couldn't ask for better
people in the high-end business to deal with.
Mofimadness "
++++1
Pradeep |
What type of sound you want will depend on your preferences and to some extent on the types of music you listen to.
In terms of what is possible, you have a very capable setup. Every adjustment (and our TriPlanars have many!) makes its own unique differences to the sound. Tweaking VTF sounds different than tweaking SRA, etc. Learning what to listen for takes time and hands-on experimentation with ears and brain fully engaged. I can fire up my system, spin an LP an know within a minute or less if VTF, SRA or some other frequently adjusted parameter needs tweaking. But that kind of awareness took years to develop, at least for me.
Read posts on this forum and others that describe what to listen for when adjusting this or that parameter. Different people hear differently, so some explanations may speak to you more than others.
And practice, practice, practice...
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The Walker method is a good place to start. It makes quite a bit of logical sense too:
http://walkeraudio.com/lloyd-walker-on-fine-tuning-your-turntable/ |
