Tracking error distortion audibility

I would argue that an arc protractor produced on thick paper is superior to the best two point protractor produced on mirrored plexiglass, laser etched stainless, etc. I won't name names to protect the guilty.

Is a paper protractor as good as a precision tool like the MintLP? You'll have to answer that question for yourselves.

I checked the above site and took a look at the excellent FAQ he wrote (the readme file). He points everyone to the fact that his protractor should be in perfect agreement with John Ellison's spreadsheet. He strongly recommends playing with the Ellison spreadsheet, so we're in complete agreement here as well.

I need to play with this a bit. Don't get confused by his inner groove radius and outer groove radius entry boxes. He is NOT talking about the null points (i.e. 66.0 and 120.9 for Baerwaald). I'll play with this and verify it against the the ones I've drawn for the Tri-Planar, and of course, against my MintLP.

I encourage everyone to play with this program. Read his excellent FAQ, and play with the Ellison spreadheet as well.

Another nice stiff paper you can use in place of photo paper is called "card stock". You can pick it up at places that sell an assortment of printer paper (e.g. Office Max).

Hint about cutting a nice record spindle hole. Use a straight edge razor and cut pie shaped wedges (8 of them) to form the record hole.

Start slicing from the circumference of the spindle hole and work your way toward the center. Cut 8 radial lines to form 8 "pie slices".

This will not only get you real close to "nuts on", but the hole will also be self centering if your spindle is a bit wider than the circumference of the hole.

After I sent samples made this way to many of my customers, they became true believers.

The only risk you are taking is that you might learn something (grin).

Cheers,
Thom @ Galibier

Just to make it clear, I wasn't trying to undersell the MintLP. The fact that we go round and round on this and it gets contentious is a bit silly - especially in light of the voluminous comments on several threads archived in this forum over the past 6 months.

All of the doubters (experienced audiophiles) became true believers, and it's not because they drank the Kool-Aid. They opened their mind to the fact that they may not be as skilled as they might have thought - that a better tool yielded better results.

My take is that it's simple for anyone with a printer to test this for themselves for the cost of a piece of paper.

To date, the only person I've encountered who can achieve the same audible results with a two point protractor as I can with an arc protractor is Frank Schroeder.

So, stop debating this, get off yer duff and prove it for for yourself. If you like what you hear, you can decide for yourself whether it's worth the $$$ to try a MintLP.

Cheers,
Thom @ Galiber

Hi Raul,

You may be one of the exceptions, and that would put you in Frank Schroeder's class of setup wizards. I was of the same opinion that you were before I started experimenting with this last Spring.

I have an old Ortofon, mirror-backed acrylic, two point protractor that I never let out of my sight. I dreaded losing it because it had very fine lines which gave me great insight into correcting for parallax when aligning at the two null points.

It now sits in my historical archive (a.k.a. "junk bin").

Cheers,
Thom @ Galibier

Gosh Feathed,

You initiated this thread asking if any of us find substantially improved tracing in the area around the null points. Well, for me, the answer is no. Distortion does not noticeably increase as the stylus departs from the null points.

So, let me get this straight. You very possibly have a sub-optimal setup, or at a minimum should find a means of eliminating this from consideration. Still, you have categorically decided that debating the choice of tools to verify this is not a topic for conversation.

No one drills the arm board where the tonearm maker specifies do they?

Why would a dealer not mount the arm according to the manufacturer's spec? I can think of two reasons: (a) Incompetence, and (b) a conscious decision based on selection of an alternate alignment.

As an example of (b), I mount both the Dynavector DV-507 as well as the Artisan tonearm to Baerwaald and not to the manufacturer's specified alignment. Of course, I communicate this to my customers as well as my reasons for doing so. Now, with a Galibier, this pivot to spindle distance is easily changed at any time due to the articulated armboard, but I do this for individuals with fixed mount turntables as well.

My reasons are that most people do not have a protractor for other than Baerwaald or Loefgren, so I derive the Baerwaald (typically) pivot to spindle distance appropriate to the effective length of the tonearm.

If you have slotted mounting holes one should always mount your arm further from the spindle so as the maximize effective length and minimize tracking error. I've not read about this but I just assumed everyone did that.

Not so ...

(a) the increase in effective length is trivial as is the reduction in distortion. You can verify this by plugging the numbers into the Ellison spreadsheet

(b) even if there were a reduction in distortion, you run the risk of compromising cartridge mounting surface's contact with the headshell and have problems with energy transfer - not a good tradeoff.

(c) assuming a fixed mount turntable/armboard, why paint yourself into a corner the next time you mount a cartridge with a "short" cantilever one whose stylus is closer to the cartridge bolts (yielding a shorter effective length) that might not allow you to achieve the alignment you intend?

You are technically correct, - that you can establish your favorite geometry around any effective length (and therefore pivot to spindle distance) as long as you have enough headshell slot length to achieve the geometry you're after. Of course, with a fixed mount turntable you've hopefully selected a pivot to spindle distance that will allow you to achieve this.

I suspect you misunderstood Brooks Berdan's intent when he explained this to you. I'm sure he was arguing that small mounting errors could be compensated for at the headshell, which is of course true. I'd have great difficulty believing that someone with his fine reputation would argue in favor of stretching the effective length of a tonearm by some 3-4 mm to reduce distortion (see points above).

Regarding alignment tools that require input of pivot to spindle length, I can't accurately measure that because of my arm's pivot design.

The MMT was made by Jelco - a company I'm quite familiar with. The bearing tower's center is fairly easy to find on these arms: http://www.vinylengine.com/library/sumiko/premier-mmt.shtml.

Assuming you want to draw an arc protractor for your arm (I maintain faith that I can "reach" you), you can back your way into your effective length using the p-s that you measured. Using the Ellison spreadsheet - set your precision level to 3 or 4 decimal places and plug in effective lengths until you arrive at the pivot to spindle distance you're after.

Again, if you play with an arc protractor printed on paper, you can make up protractors that bracket around this effective length - to compensate for a measuring error on your part. One of them will be "right". Given the opportunity to produce an arc protractor on a laser printer for any effective length, why would you not go through the exercise of trying this?

What about alignment of the stylus to the cantilever? A misaligned stylus renders all methods discussed above (except maybe listening) null and void. They are utterly and completely useless.

Bingo! You have made yet a further argument in favor of an arc protractor. With a two point protractor, you're trying to line up the cantilever at the two null points. If you try to deviate from a lined up cantilever with slight clockwise and counterclockwise rotations, you'll go crazy trying to keep it straight in your head.

With an arc protractor you can vary your offset angle in both directions, knowing that you've maintained the correct effective length because you have the arc for verification. In other words, you can separate the variable of offset angle from overhang.

You have just (again) argued in favor of using an arc protractor.

Cheers,
Thom @ Galibier

Hi Feathed,

I'm sure any competent person would not make the errors you cite above

Well, that leaves the other possibility - that they are misinformed. It's no crime, and I surely have a lot to learn as well as the next fellow. Frankly, this is one reason I post on this forum. No one can know everything, and collectively, we are all better for the exchange.

OK, I'll do some work for you and for Brooks. Based on the Ellison spreadsheet, here are the distortion numbers for 239mm and 243 effective lengths:

Effective length = 239mm:

at 57mm = 1.16%
at 146mm = .62%

Effective length = 243mm:

at 57mm = 1.14%
at 146mm = .61%

As far as references are concerned, I primarily use the two appendages on the side of my head along with all of the other individuals who,like myself thought that years of working with two point protractors yielded as good results as you could reasonably expect to achieve. I don't know of a single individual in my listening circle who still has this opinion.

I'm going to be in So. Cal in a couple of weeks' time, and had planned on visiting Brooks. This thread gives me one more topic of conversation. Brooks is someone I've admired for quite some time. If indeed your memory of your conversation with him is accurate, then I'll take the opportunity to set him straight.

Cheers,
Thom @ Galibier

Feathed,

Your longer effective length calulations show lower distortion and there is NO downside. You just proved the point. You claim to respect Brooks and you don't know everything yet you will "set him straight".

.02% (that's .0002) is not audible, and even if it had some marginal effect, all other variables need to be taken into account in order to understand the cost (if any) of this small gain. One needs to remember that this is a sub-system and not a single isolated parameter.

As Raul correctly points out, all design and implementation parameters of a cartridge/tonearm sub-system are interrelated with each other. I pointed out one potential downside to extending the cartridge to the very front of the headshell in my point (b) above - the possibility of compromising headshell/cartridge interface.

Because I respect Brooks does not mean that he is any more infallible than I am. I walked a fine line in my comment, and gave you the benefit of the doubt that you understood Brooks when I wrote: "If indeed your memory of your conversation with him is accurate, then I'll take the opportunity to set him straight."

Can you help me understand why I should believe that you are accurately conveying Brooks' explanation any better than you are assimilating Raul's and my comments?

Thom @ Galibier

Hi Pryso,

The forward position of the stylus relative to the cartridge mounting holes is more of a statistical norm than an industry standard. Frank Schroeder has observed this norm to center around 9.25mm.

I know the ZYX (Airy-3 and Universe) come in at 9.00mm, and the Dynavectors vary, but in general fall into the 8.00 to 8.25mm region. I haven't compiled as large a database as Frank has, but don't doubt his 9.25 number.

SME's assumption is that you can compensate for these small differences in effective length by moving the arm for and aft in the track, to arrive at a workable combination of effective length (as dictated by your cartridge) and overhang/pivot-spindle.

In my early days at Galibier, I advocated this as well, using the articulated armboard to adjust pivot to spindle distance. To a certain extent, I trivialized the importance of offset angle as does SME.

While I now advocate the use of an arc protractor (certainly for precision in setting of effective length and overhang/pivot to spindle parameters), the importance of offset angle is still one that I would like to explore further.

In a conversation with Yip at MintLP, I posited that offset angle might be considerably less important than dialing in the effective length/overhang parameters (tracing the arc perfectly). Yip has been thinking the same thing.

Both of us however have been respecting all three parameters, and need to experiment with the effect of screwing this third one up (offset angle). Of course, with an arc protractor, it would be a simple matter of separating offset angle from the other two variables (e.g. tracing the arc) in order to observe the effects.

I'm thinking out loud here, but as I visualize the solution, a clockwise rotation of the cartridge (relative to that dictated by Baerwaald for example) would have the effect of shifting both your null points toward the record spindle. So, with a Baerwaald arc, you'd have an alignment that slightly favored the inner grooves as does Loefgren.

I need to both think this through as well as play with this a bit.

This concept of optimizing for the inner grooves at the expense of overall higher distortion in the majority of the record is an odd one to my way of thinking, yet I understand why the fellow who listens to large, romantic works with big climaxes might make this choice.

Back to our old friend, the SME ... Of course, there are two reasons for having a bit of play in the holes in the headshell holes - both of them relating to adjusting the offset angle: (a) due to an alternate effective length dictated by the fore/aft position of the stylus relative to the cartridge holes, and (b) to correct for "out of true" cantilevers resulting from normal production variances.

It's been too long since I owned an SME (an original Model V), but I don't recall much play in the cartridge holes in the headshell. I recall one poster commenting on this forum that he opened up the diameter if his holes a bit in order to play with offset angle.

Cheers,
Thom @ Galibier