Ketchup, I was not aware of that feature on the ET arms. Very interesting It is pretty cool. I don't know of any other arm with this feature. After I posted above, I realized that the height of the ET2 arm can also be adjusted to compensate for vinyl of differing thicknesses without moving the bearing housing in an arc (which you would not want to do in this case because that would effect overhang). To do this, you move the arc block up and down on the post. So, you can either move the bearing housing up and down on the arc block to adjust SRA without effecting overhang or move the arc block up and down on the post to adjust arm height for vinyl of varying thicknesses, also without effecting overhang. Moving the arc block on the post is not as easy and can't be done on the fly like moving the bearing housing on the arc block, but the capability is there. Bruce Thigpen thought of everything when designing the ET2! |
Sarcher, That's better. Maybe it was use of terms, not sure.
Anyway, "The people that try to get the perfect SRA for every record must believe that it's more important than perfect alignment. I doubt there are many people that would go to the trouble of adjusting overhang for every record as well."
I know that's taken out of context, but that perception was what I was addressing by statements about percentage of records needing correction, and viability of resultant alignments. If SRA is set for 92, then additional SRA angle results in less overhang from raising the arm. It's true that angle changes slightly but less overhang would put a Baerwald alignment a hair closer to Stevenson. A small change in height results in a much smaller change in overhang, depending on eff length, plus most records don't need correcting.
After many thousands of records, it's a trade-off I might make to optimize SQ. Hence the popularity of on-the-fly adjusters. The only problem with some of them, is they compromise mounting integrity. Some linear arms are a particular problem with respect to changing SRA, those with a short arm tube.
Regards, |
Ketchup, I was not aware of that feature on the ET arms. Very interesting.
Some say that the tracking error of linear arms is actually more than pivoted arms because of the higher horizontal effective mass. This causes the cantilever to deflect more than is optimal and creates tracking error.
I don't own a linear tracker so I have no personal experience with that. At the last RMAF I spoke with Peter Ledermann of Soundsmith. With his new Hyperion cartridge there is an option for a suspension optimized for linear trackers. Horizontal compliance is lowered while the vertical compliance stays the same. This stops the cantilever from deflecting too far. This in turn lowers distortion. This sounds like a good idea. I'm not sure if that option is available for his lower end carts though? |
Fleib, I'm not confused. Yes Lofgren B has the least average distortion. But Lofgren B also has the most max distortion. Meaning that at the beginning and the end of the LP the distortion is higher than the other alignments but in the middle of the LP the distortion is lower than the other alignments. It's a compromise.
We are not really saying different things. We are just expressing it differently.
From what I've read the distortion gets higher towards the inner grooves because of the tighter radius. It seems to me that you want to minimize distortion at the end of the record. Lofgren B has the most distortion at the inner and outter grooves. I would think this should be avoided unless you are playing discs that have no music on the inner gooves. Like most of the newer 12" 45's I have gotten. I also have some double LP's that don't use much of the inner grooves either. |
Sarcher30, I didn't mean to imply that you took a position, that you really didn't. I should have addressed my last comment to "anyone who". Sorry.
As far as the various alignments, you still have them mixed up. Baerwald goes for even error at beginning, middle and end. Loefgren B has least total error. Maybe description on VE is confusing, but nevertheless.
Regards, |
Sarcher30, the mat I'm referring to is not the "Way Excellent" mat; it's the "Donut" mat found at the bottom of the Herbie's Turntable Mat web page. It's basically the elastomer wafer of the "Way Excellent" mat without the silicone foam base. The "Donut" is not intended to absorb vibrations so it's sonically inert for the most part. That's why I found it to be a good method to adjust for LP thickness and SRA on the Gyro SE.
Theo, I'm not familiar with the Linn 12 platter so cannot say if it will work the same as for the Gyro SE. But I will add that I also use a "Donut" on a Music Hall mmf-7 turntable, which has an acrylic platter, and the results are similar. The main difference is that I use a Way Excellent mat on the mmf-7 and it compresses slightly so I use the 0.81mm "Donut" to account for the compression.
Regards,
Tom |
I view perfect alignment if the stylus touches the inscribed arc at any point on the Mint protractor |
Theo, The Herbies Way Exellent II Mat is what I think Tom is referring to. I have one and have used it on a LP12. They are fairly light and work well on the Linn. They do make them in many different heights.
On my current TT I prefer a harder mat though. |
Fleib, I'm not sure where I wrote that SRA does not matter. I don't feel that HTA is necessarily more important than SRA. It's all important and all we can do is optimize all the dimensions the best we can. I also do not think that small adjustment of VTA without resetting HTA is wrong. I was just pointing out its effect on HTA.
As for Stevenson or Baerwald you gotta go with what sounds best to you.
I just looked at the vinyl engine calculator again and it shows Baerwald as having the least max distortion and Lofgren B as having the most max distortion. Lofgren B has the least average distortion though. Baerwald has less max and average distortion than Stevenson so I can understand why it is popular. |
Tom
Thanks, I didn't realize the "donut" excisted. And i gatehr from what you are stating that you have found it to have no effect on sonics? I wonder how it would perfom on a suspended table like my LP12. I guess I should research this as an option. |
The only way the offset would not move when adjusting VTA up or down is if the tonearm post was curved. The Eminent Technology ET 2 tonearm has a curved post for this exact reason. The part is called the arc block or VTA block. The arc block is stationary and the bearing housing rides the arc of the arc block as VTA is adjusted to keep overhang dead on. |
Hi Searcher, Actually, Baerwald (Loefgren A) is least average error across the entire record i.e. even amount beginning, middle, end. Loefgren(B) is least total error. That's because nulls are closer to the middle where error is the greatest, but error is a little higher at the beginning. Stevenson puts the inner null at the lead out groove to help with inner groove problems. There's no right/wrong. I've aligned many arms designed for Stevenson with nulls between there and Baerwald. IMO it worked out better.
Why only consider horizontal aspect? Tracking is 3 dimensional. If SRA is off, it effects playback of the entire record. If someone finds occasional height adjustment to sound better than not, how can you question that? |
Fleib, I can't really argue with what you're saying but what I mean by perfect alignment is least distortion. For pivoting arms this means least max and/or average distortion for horizontal alignment. Have a look at the alignment calculator on vinyl engine. If you play with the null points and or different alignment such as Stevenson or Baerwald it will show the maximum and average distortion for each choice. For least maximum distortion Baerwald is the way to go.
Can you hear it if it's a little off? I think so if your system is resolving enough.Is it a big difference? Not really. |
Theo, adjusting for differences in record thickness (weight) is exactly what I do using a Herbie's "Donut" mat. I use a 0.5mm mat to compensate for the thinner 120g-150g LPs. Actually, I'm compensating for the heavy 180g-200g LPs that I started purchasing a few years back; I noticed that SRA was changing slightly with the thicker LPs. So now I set up my cartridge alignment and tonearm height for proper SRA using one of my best 180g LPs (even thickness and flat) and then use the "Donut" mat to raise the thinner LPs up off the platter. It's not an elegant solution like the VTA adjusters on some tonearms, but it works.
The 0.5mm mat was a compromise because it actually works for a small range of LP thicknesses. (Refer to chart below.) I tried using a 0.8mm mat for the thinnest LPs (100g-120g) and used the 0.5mm mat for 130g-150g LPs but found that dealing with two mats wasn't worth the additional benefit for the lightweight LPs. They comprise a minority of my LPs so I can live with it. I'd rather set things up to optimize for the majority of my records and the high quality heavy vinyl.
Thickness/Weight
1.00" / 100g
1.27" / 120g
1.52" / 150g
1.77" / 180g
2.02" / 200g
I found the "Donut" to be sonically neutral using it with a Gyro SE platter. I'm not sure about other platter materials and construction.
Regards,
Tom |
Where did the notion of perfect alignment originate? It is only tangent at 2 points throughout the record side, whatever alignment you choose. Wax poetic about your wonderful alignment, but it is only choosing one set of errors vs another.
What about the null throughout the record, when the stylus is or is not vertically aligned with the angle/cut of the groove undulations? Why is that unimportant, because Roy Gandy can't hear it, or it's cheaper to make an arm without height adjustment?
In reality, if your arm height is set so SRA is right for the "average" record, it won't have to be changed for every one. The majority of records will sound right. But for the occasional record that is obviously off (assuming you can hear it), a small change in height will have little affect on horizontal alignment, and great affect on vertical alignment.
Regards, |
Reading these posts made me break out my MINT protractor and check the alignment again....its still perfect. I adjusted the arm so that it is absolutely level and I leave it that way, no matter the thickness of the record that I play. I know that it may sound better with the back end up or down, but I don't really care. I depend on the cartridge manufacturer (Benz) to provide the proper angles of the stylus. The sound is excellent to these ears. |
I adjusted the VTA today by lowering the back of the tonearm. I then checked the overhang, and the adjustment in the VTA did indeed appear to change the overhang, but too insignificantly to take notice. Admittedly, I changed the VTA very slightly, and I acknowledge that bigger changes might indeed affect the overhang to a more significant degree.
I find it curious that this is never mentioned when the VTA is discussed. As I mentioned in my previous post, you have to wonder about the utility of the VTA on the fly adjustments. To me the entire idea was that it allowed real time adjustments while keeping other variables constant. I suppose if the changes are minuscule, I can still see the benefit, but this does seem to warrant at least some discussion.
Btw, is Doug on vacation? This thread begs for his input. Doug, chime in! |
Peter, The people that try to get the perfect SRA for every record must believe that it's more important than perfect alignment. I doubt there are many people that would go to the trouble of adjusting overhang for every record as well.
I'm sure someone could design an arm with a curved VTA tower with on the fly adjustment. It probably would not be worth the effort as I imagine it would be quite difficult to accomplish. It would be allot of work for a little gain in accuracy. |
Sarcher, you are absolutely correct that raising or lowering the VTA the same amount as the LP thickness difference will preserve the original alignment. There, I knew I would learn something and this is so obvious.
However, some of the people I know change SRA for different records by listening and trying to duplicate the original cutting angle. This is independent of record thickness as there is/was no standard cutting angle, though most I guess were around 92 degrees. For these people, changing SRA does indeed alter alignment. Perhaps to such a small degree that it is not an issue.
And as Audiofiel wrote, life is too short. I set SRA with a 150-160g LP and leave it, obsessing no more. However, I do spend 20 minutes per side cleaning an LP, because it sounds better to me, so we make our choices, even if they are inconsistent. |
One thought I have that has crossed my mind a few times in the past when thinking about LP's varying thicknesses. Why hasn't someone come up with either a shim or different thicknesses of mats. Then one could place a thicker shim or mat on the platter for standard pressings and revert back to the standard mat for the 220 gram recordings and have one of each for 120,140,180 gram etc.
I realize there may be different sonic signatures for each mat or shim, but would it be that noticable if they are all the same material. I am curious from a mechanical point of view that over time the constant changing of the tonearm in such a small incremented area of the adjuster, what wear will eventually reveal itself. Just a though and love to hear the shortcomings of this idea. |
The problem is twofold, overhang changes with arm height and SRA varies from 91 to 95 degrees. Even Jon Risch* (the guy whose work this is based on) said that 91 degrees is right for 80% of all records. In reality, I think most people who occasionally change arm height for a record, usually change it a small amount. A 9" arm requires 4mm height adjustment for 1 degree change. Who set up the alternatives of changing for every record, or not at all?
If you use a Loefgren A or B alignment set at 92 degrees, then raising your arm slightly won't do much to alignment. Any two set of nulls between 60 and 121 mm, is a "good" alignment. Look at the nulls for Loefgren A, B, and Stevenson. If you're skeptical, get a straight line calibrated grid, raise your arm 2 mm and see where the nulls are. IMO SRA errors can be much more audible. Some people don't seem to hear it, but some people are nearly oblivious to speed variations.
Put a UHQR on your table, and in order to maintain your orig alignment the arm must be raised the same amount of extra record thickness. Look at the record and arm pillar as 2 sides of a right triangle. The arm tube to stylus is the hypotenuse. The alignment change is very small and SRA goes negative, Sound a little bassy?
*Audio magazine March 1981 |
Actusreus, The only way the offset would not move when adjusting VTA up or down is if the tonearm post was curved. Lets use your fork as an example. If you lift your fork without moving the front at all it will trace an arc in the air. Turn the fork on it's side and put it on a piece of paper. If you attached a pencil to the end and rotated it keeping the tongs centered, it will trace an arc. Unless the tonearm post can trace that same arc it will effect overhang when adjusted. |
Audiofeil, I'm with you there. I don't personally adjust VTA for every record either, but I think it is important to know how different adjustments effect things. Especially when setting up a cartridge.
If you don't adjust VTA for different height records then make sure you set your alignment on a medium thickness record. Unless you mostly listen to 120 or 200 gram pressings. This is what I do.
All that said I can understand why someone might want to adjust VTA for different record heights. Most people don't have the time or patience to fiddle with it. Myself included. |
Sarcher30
Actusreus, your fork analogy does not work. If you could lift the rear of the fork straight up without letting it move forward as you lift it would pull the front back. This is quite easy to test with your tonearm. Just setup your alignment protractor and play with VTA. It's easy to see. Sean and Peter, Remember that you're not actually moving the tonearm, but the VTA tower or essentially the column that is supporting the tonearm. So in my fork example, if you threaded the back of the fork and inserted a screw that would allow only vertical motion, you could move the back of the fork without pulling it in or out. I will adjust the VTA today on my table just of out curiosity. I know Doug adjusts the VTA for each record so it'd be interesting to hear his opinion on the matter. |
Peter, What happens when you use a taller record than the one you used to set your alignment? A taller record will push the stylus forward a bit. By adjusting VTA up the correct amount you compensate for that. So adjusting VTA for different height records preserves the correct overhang as long as you adjust it the correct amount.
Sounds like you just made a case for VTA adjustment not against it. ;0)
Unfortunately there is no way to account for record warps as they will surely change overhang as well. Even clamping and or vacuum hold down will not remove all the warps.
Sean |
Good topic Peter. I have noticed this effect as well.
Actusreus, your fork analogy does not work. If you could lift the rear of the fork straight up without letting it move forward as you lift it would pull the front back. This is quite easy to test with your tonearm. Just setup your alignment protractor and play with VTA. It's easy to see.
Now as long as you only make small changes in VTA it may not be necessary to reset your alignment. It depends on how anal you want to be.
When setting up a cartridge I rough in the weight first then rough in the SRA. That way when you set the alignment it won't change as much when you dial in VTF and VTA. It does make sense to readjust overhang as a last step. If you change VTF and/or VTA significantly afterward you should also reset overhang. Most people don't take that into account though.
Sean |
I'd rather listen to music and compromise on "ideal playback" than adjust my tonearms for every record.
Life's too short IMO. |
Theo, You can refer to my system page. I have an SME 12" arm. As such, it requires a greater increase or decrease in VTA to effect the SRA than it would with a 9" arm. Similarly, the offset angle at the headshell is less than with a shorter arm, so skating force is not as great. Also, SRA changes during warped records are not as great.
Actusreus, I believe you are mistaken. As mofimadness pointed out above, changes in VTF, even very slight, do change overhang and thus alignment as the effective length of the system (pivot point to stylus) is altered as the cantilever changes angle due to the greater or lesser tracking force. Your fork analogy is a good one. As you raise the end of the fork the teeth will indeed move in or out. Remember, your lifting hand must move vertically only. Imagine a very short fork and movement up or down of one inch.
Even though a small VTA adjustment only changes overhang very slightly, and it may not be audible to all, overhang does indeed change, changing cartridge alignment. I believe this is a geometric fact.
I'd like to hear from those who change VTA for different LPs if and how they account for the change in overhang. Mofinmadness understands the issue. I'm trying to learn if it is more theoretical than practical. |
Peterayer,
I don't quite understand your triangle illustration, but you seem to be making an assertion that as you move the arm up or down, you pull the stylus in or out. I just don't think this is correct. Perhaps large VTA adjustments might result in stylus displacement, but I just don't see why small changes in VTA should result in overhang changes. The simplest illustration I can think of is lifting a fork that is placed teeth down on a flat surface. You can certainly move the back of the fork up and down without bringing the teeth on or out; you only change the angle at which the teeth and the surface interface.
If you were correct, any tonearm designer who offers VTA adjustment on the fly would not understand the basics of cartridge alignment, which is absurd. My guess is you're doing something else to the alignment as you adjust the VTA that would explain the overhang changes you noticed. |
Peterayer as it appears, I tried to edit my secon post to which you refer, and it vanished! But what I wanted to add is that I had omitted from my thoughts that you are working witha 12" arm whereas mine is a 9" arm. Those changes would be more dramatic in the geometric sense than I was thinking. I appreciate your response, although it may not make sense to anyone that hadn't read what I had said before as it is gone now. Maybe someone who has actually made these change and adjustments in compensation for each album thickness can enlighten us to their personal
experience. It will be interesting to read and learn although I for one will probably make some minor adjustments to my arm now that the SRA has been set to bring it to the sound I like and settle on it as a happy medium. But my arm is a Ekos and it isn't as accomadating for frequent adjustment. Someday if Graham ever does develop a proper spring for the LP12 to support at Phantom properly, I will look into that, budget permitting. So maybe it was a good thing my second post vanished as I was in error. But thank you for your reply and the explaination. By the way you didn't mention what arm you are using, just to satisfy curiousity at this point. |
As one who has set-up hundreds and hundreds and hundreds of tables/arms/cartridges, I can attest to the fact that as you change VTA/SRA, it will also change the overhang.
As Peter states above, as the back of the arm goes up, the tip of the stylus moves in. As the back of the arm goes down, the tip of the stylus moves out.
That's why if you make a change in one, you must recheck the other. Just like VTF will affect VTA/SRA.
I agree with Peter that if a user is changing the VTA/SRA for each record, they should also check/change the overhang.
I've always kind of thought that the changes one hears by adjusting the VTA/SRA, might be due to the overhang change as much as the change to the VTA/SRA? Just my take... |
Certainly no offense taken, Theo.
Let me try to explain my point again. Here's my thinking: Imagine that the following three points form a triangle as viewed from the side. The first point is center of the arm tube intersecting the arm bearing point or line. The second point is the stylus tip. The third point is at the center of the arm tower at the plane of the record. Now imagine raising the VTA. Point #1 moves up. This pulls point #2, the stylus tip, slightly in toward point #3. An extremely short arm tube helps to illustrate the figure. The fact that the stylus tip moves relative to point #3 means that overhang changes as VTA changes.
If viewed from above, the stylus tip is now inside the original arc that the stylus traced across the LP. Or if it were possible to swing the arm all the way in toward the center of the LP, the stylus's relative location to the spindle changes as VTA changes. This is overhang, or Horizontal Tracking Angle (HTA).
I confirmed this effect tonight by observing the relationship between my stylus tip and the arc on my MINT LP protractor as I raised and lowered my VTA. When I increased (raised) VTA, my stylus tip moved inside the arc (more at the outer groove). When I decreased (lowered) VTA, my stylus tip moved outside the arc (again more at the outer grooves than at the inner grooves).
Now, I'm talking specifically about VTA. I recognize the importance of trying to match the SRA to the original cutting angle. Fremer recommends 92 as the closest compromise for the most LPs. I also understand that altering VTA effects SRA. I also agree that HTA which I think you refer to as Tracking Angle may not be as important as setting the correct SRA.
For the purposes of this discussion, I'm only looking at the relationship between VTA and HTA.
I'm just trying to make the point that as one adjusts VTA, overhang changes. This effects cartridge alignment and is quite audible. The closer my stylus is to the arc traced on my protractor, the more information my stylus extracts from the grooves and the less distortion there is.
Once the arm and cartridge are properly aligned, all should be fine. I'm just wondering what if anything those who adjust SRA by lifting or lowering their arms for each LP do to address the change in overhang which results from the change in VTA. I hope this clarifies my original post and like you, I'm just trying to learn something. |
Why would the overhang change when you adjust the VTA? It seems to me the only other setting that should be affected is the SRA. |
Theo, I think you are referring to an SRA of 92 degrees. I have met MF and listened to him discuss this topic and it makes sense to me and I have viewed my stylus through a USB microscope and tried to calculate the angle. I do my final adjustment my ear.
My point is that I was surprise by how much the overhang changed when I adjusted my VTA/SRA by lifting the back of my arm. I have settled on one height and corresponding SRA angle and leave it at that. I don't plan to adjust my VTA for each LP.
My questions is really for all of those analog guys who purport to adjust THEIR VTA depending on which LP they have spinning on their platters. I am wondering if when they raise or lower their VTA (on the Graham, Tri Planar, Durand, whichever arm makes this easy) they are taking into account the resulting change in HTA or overhang. The cartridge's alignment changes with changes in VTA and I'm not aware of audiophiles realigning their cartridges with each change in VTA, that is with each LP.
Thanks for the suggestion to contact Rick, but I'm all set with alignment and settings. |
If your read Fremers article a few months back in Stereophile he emphasizes that the Rake Angle is more crucial to the playback of lps. I recently had mine adjusted and I will attest that Fremer is correct. I attended the Music Matters gathering at Audio Alternative in Fort Collins he refers to in this months Analog Corner. And he touched on this subject that night as well. It makes perfect sense to me that we strive to approach the groove with our stylus at the same angle as it was cut or scribed when the orginal stamper was made. So I would suggest, and this is only intended as food for thought, that you look into that setting as your reference point and adjust from there. If you are in Colorado or nearby give Rick at Audio Alternative.com a call and make an appointment. He has mine TT and Cart working at peak performance. |
