[Sonny]

Hi there, I was wondering if any has an alignment tool that they think could work with a VPI jmw 10 arm, which has the following characteristics:

Spindle to Pivot = 250mm
Overhang = 15mm
Headshell off-set angle = 22 degrees.

I'd love to borrow it if possible.  I know the Wally Tractor is great, however, being just laid off from my job, I can't afford to buy it.

Any help is appreciated.

Thanks
Tuan

PS, I am located in the SF bay area!

[planet10]

http://www.vacuumstate.com/index.tpl?rubrik=4&lang=2&a=v%25C9%25D5%2508%25A4%2508%25AE%258C&b=733795.2837762678

dave

[GBB]

Hi there, I was wondering if any has an alignment tool that they think could work with a VPI jmw 10 arm, which has the following characteristics . . .

I'd love to borrow it if possible. 

Tuan,
There are some good and cheap alignment gauges out there.  The Turntable Basics gauge looks pretty good and only costs $20.
http://www.turntablebasics.com/


The tricky part is getting the gauge aligned / sighted with the pivot of your tonearm.  If you do that accurately then the alignment will be as good as anything out there.  The use of a mirrored gauge is really helpful since it lets you align the stylus of the cartridge directly and accurately as opposed to aligning the body of the cartridge and assuming that the stylus is perfectly aligned to the body.  I've got an alignment tool called the Cart-a-lign which is similar but it's no longer manufactured.

One can buy pre-made tools that are optimized for a single tonearm geometry that eliminate the need to "sight" the gauge to the tonearm and people seem to really like these.  I've not used one.  The Wally tractor is the best known version but it seems to be unobtanium.  MintLP makes a similar gauge and they seem to be in business and easy to work with.  But their tool costs $110 which may not be the best option for you right now.
http://www.mintlp.com/best.htm

Let me know if you want to borrow my alignment tool.

---Gary

[Wayner]

Those are horrible numbers. They make my Baewald calculator go off the chart. First null point is probably on the spindle, the second null point is 145mm and the distortion is 1.114%. I'd recheck your arm specifications. Something wrong.

Actually if you used 265mm (250 spindle to arm), 15mm overhang, and 20.5 degrees offset, the calculator looks great. Distortion is down to .414%

Wayner 

[Sonny]

Those are horrible numbers. They make my Baewald calculator go off the chart. First null point is probably on the spindle, the second null point is 145mm and the distortion is 1.114%. I'd recheck your arm specifications. Something wrong.

Actually if you used 265mm (250 spindle to arm), 15mm overhang, and 20.5 degrees offset, the calculator looks great. Distortion is down to .414%

Wayner 

Thanks Wayner...
Yes, it's very strange, the VPI Jig... But I do think that the right distance is the 250mm plus the 15mm overhang...it's really a matter of cartridge alignment.

The strange thing is, my original VPI jig, the older white one, has a null point of 66mm from spindle but when I asked for a new one, VPI sent me one with a null point of 68.5mm.

Anyways, I am playing with a jig made by Seb on the Vinyl Engine, will give feedback on that over the weekend. 

the idea of the Cartridge Alignment tool from Turntable basics is intriguing and I may have to try that.

Thanks guys...keep the feedback coming!

[Sonny]

http://www.vacuumstate.com/index.tpl?rubrik=4&lang=2&a=v%25C9%25D5%2508%25A4%2508%25AE%258C&b=733795.2837762678

dave

Dave, have you tried this?  moving the cartridge / stylus back 1.27mm from the spec?
If so, how does it sound?
T

[Wayner]

The only real problem is the offset angle. 22 degrees is bad, 20.5 degrees is good.

20.5 degrees puts null points at 63.3mm and 121.4mm

Wayner

[Sonny]

The only real problem is the offset angle. 22 degrees is bad, 20.5 degrees is good.

20.5 degrees puts null points at 63.3mm and 121.4mm

Wayner

Hm...
well, that makes sense to me.  But if I use the classic baerwald and the mounting distance of 250mm, I should get the right effective length and cartridge angle, no? using the Seb Protractor...from Vinyl Engine
I am going to try the Guru as well this weekend.
T

[BobM]

I'm a little confused with the Guru instructions. I don't think you are actually moving the cartridge back in its mounting to the head. That would change the overhang and effective length. I think you're just using that slight offset to then align the cartridge sides. I too plan on trying this this weekend and see if I notice much of a difference.

My cartridge is a HOMC (20X-H) and is far less finicky than most LOMC's, so I'm not sure that I'll hear much of a difference. But then, I still have a hard time believing I hear a difference between different kind of stings used to spin the platter, but I do.

We'll see.

Thanks,
Bob

[Wayner]

No. There is no such thing as one protractor fits all. It is geometrically impossible. You can hit 2 points on an arc with a different arc, but that is it. Distortion values increase, tracking errors increase. The distance between spindle (center) and tonearm pivot (center) can't be changed (in most machines) therefore you can only adjust overhang and offset to mimic a close likeness to the original theoretically perfect curve.

Wayner

[Sonny]

I'm a little confused with the Guru instructions. I don't think you are actually moving the cartridge back in its mounting to the head. That would change the overhang and effective length. I think you're just using that slight offset to then align the cartridge sides. I too plan on trying this this weekend and see if I notice much of a difference.

My cartridge is a HOMC (20X-H) and is far less finicky than most LOMC's, so I'm not sure that I'll hear much of a difference. But then, I still have a hard time believing I hear a difference between different kind of stings used to spin the platter, but I do.

We'll see.

Thanks,
Bob

bob,

The Guru IS suggesting that you move the cartridge back to the Guru's recommendation, which is 1.27mm back from your alignment...and then, if done perfectly, you should not have to adjust (align the cartridge).

[Wayner]

This is a hard thing to explain. let me try harder. There is a geometrical relationship between 3 values. They are pivot (center) to tonearm (center), overhang (these 2 values give you the effective arm length) and offset angle.

Next, you have to understand that all tonearm and turntable manufacturers made their stuff with these specifications all over the place. I think most of it was because of marketing, or maybe they thought their numbers were better then the next guys.

As the distance between the tonearm pivot and the spindle increase, the offset angle decreases. Lets say your tonearm was 10 feet long. The offset angle wouldn't hardly bee anything, because that huge arc started to mimic a straight line (that is how the record masters are cut, on a linear cutting lathe). As the distance between the spindle and the tonearm center get shorter, the angle increases, so does the distortions because a short arc doesn't match a straight line very well at all.

The 2 null points are spots on the record that a few guys like Baerwald, Lofgren and others, figured out. With their respective theories and formulas, they determined where these 2 spots are. What is so amazing about the 2 spots? That is where the arc crosses the straight line path and the stylus is perpendicular to the straight line. When your cartridge is aligned properly, it crosses the straight line at these 2 points. The known distortion values for tracking (error and distortion) are the least. If you have a linear tracking table, you don't have to worry about this 'cause the arm  travels in a straight line. All you  have to do then is get the stylus in line with the center of the spindle (centerline).

As different values are used from spindle center to tonearm center, the 2 points start to shift one way or another. If the first null point is out of the groove area and onto the label area (like Rega likes to do) then the distortion raises at the beginning of the record, cause the 2nd point is closer to the label. However, the distortion is less at the end of the record.

So as you can see, there are an almost limitless number of positions the null points can be at (within a range) and that will affect your offset angle.

The problem with the one protractor fits all now becomes obvious. If your table hasn't been designed to the same parameters as the protractor, you will be miss-aligning your cartridge. Some tables are very, very close and then this is not a problem. Some are very far away and this will cause bad distortion and undue record wear.

Whew!

Wayner  

[Wayner]

The 2 spots where it says 90.000 degrees are the only 2 spots where the sweeping tonearm and the cutting lathe tonearm crossed paths. The rest of any spot you pick is not 90.000 degrees.




Hope this helps, more.

Wayner 

[Sonny]

http://www.vacuumstate.com/index.tpl?rubrik=4&lang=2&a=v%25C9%25D5%2508%25A4%2508%25AE%258C&b=733795.2837762678

dave

Hi there,
just wanted to say that Seb, at Vinyl Engine has graciously sent me his protractor with the mounting distance of 250mm and Baerwald method.  I have tried to hone it in as accurate as possible and will have to play with it this weekend, but here's what Seb wrote about the Guru's method.... http://www.vinylengine.com/guru-protractor-analysed.shtml  Remember, he did mentioned that with the Guru's method, the calculus doesn't make sense, but it's about faith.
T

[GBB]

There's an interesting article describing the effect of different alignments on the JMW 9", 10", and 12" arms over at the vinyl engine.  Take a look at:
http://www.vinylengine.com/vpi-tonearm-geometry.shtml

For the 10" arm, the geometry of the different alignments are shown:



And then the effect of the different alignments on the distortion is shown:



All of the alignments seem to show an offset angle close to what Wayne predicted.  So perhaps your original angle of 22 degrees is in error.

---Gary

[bacobits1]

This is interesting.
I'm using a Rega RB300 arm on a Basis 1400.
I do not know the pivot to spindle distance or any other measurements.

I use the db protractor and a small old card printed Protractor by Stereophile for quick setting up.
Now, I printed the Guru/Vacuumstate protractor and checked the alignment for kicks.
My cartridge sets exactly on the Guru alignment by chance. I did not move a thing.
I have to say my table never sounded better. Is it because of this alignment I didn't even know about?
I'm not going to question it. I have to say it sounds friggin' good since I set it up 2 months ago and not messed with it.
I have to keep tell myself not to mess with anything.


D

[Wayner]

The distance for a RB300 on Rega tables has a design intent of 222mm spindle center to tonearm center. (223 according to others). 222mm = 8.740", 223 = 8.779". You can roughly measure it that with a tape measure to see if your table/arm combination is in the ballpark. Rega chose a different route than most by putting the first null point out of reach of the stylus (like in the label area). That raises the distortion at the beginning of the record, but reduces it at the end (which kind of makes sense) where there is music compression anyway.

Wayner 

[BobM]

Tried the Guru method over the weekend and it sure does sound nice. I can't say that there was any significant difference between the regular setup and the Guru method for alignment, but it certainly didn't cause a problem.

The nicest thing about the Guru link and paper was the description of setting anti-skate. I've never seen anyone describe what to listen for and how to go about figuring out what is proper. This is the first time I've seen ANY method at all for this setting. Well, it did work for me as described. I was able to identify a range where the sounds they describe came more into focus dynamically, so I guess I can say that it works as described.

In any case, the adjustments over the weekend playing with the Guru methods helped me to readjust my cartridge alignment, which I needed to check anyway. So it was a good use of a 1/2 hour anyway. It's all good.

Enjoy,
Bob

[Sonny]

Tried the Guru method over the weekend and it sure does sound nice. I can't say that there was any significant difference between the regular setup and the Guru method for alignment, but it certainly didn't cause a problem.

The nicest thing about the Guru link and paper was the description of setting anti-skate. I've never seen anyone describe what to listen for and how to go about figuring out what is proper. This is the first time I've seen ANY method at all for this setting. Well, it did work for me as described. I was able to identify a range where the sounds they describe came more into focus dynamically, so I guess I can say that it works as described.

In any case, the adjustments over the weekend playing with the Guru methods helped me to readjust my cartridge alignment, which I needed to check anyway. So it was a good use of a 1/2 hour anyway. It's all good.

Enjoy,
Bob

Good to hear Bob, so all you did was place the Guru's protractor on your platter, put your cartridge on the green arrows, then moved it back the 1.27mm, and viola!

Sounds easy...enough.

I actually got my rig running nice as well, finally and played the new re-issued Rickie Lee Jones LP POP POP and it was great!  Listened to Sonny Rollins' Way Out West on Analogue Production's re-issue, and that was wonderful!  Dynamics were amazing!  Don't know if I should try the Guru as things sound good right now.

In regards to Anti-Skating, unfortunately, w/ the VPI arm, there is limited adjustments...

T

[BobM]

Actually, it's more of twisting the body to align with the lines on the Guru protractor. It's not moving the cartridge backwards (thereby affecting the overhang and effective length, which you don't want to do). It's just a realignment of the cartridge squarely to the groove.

Bob