Hi all,
As far as using the designer’s intended alignment, this is one of the few areas where I say experiment (ignore the designer) and see what works for you.
Assuming a fixed mount on your tonearm (meaning that you can’t change your pivot-spindle distance), then the overhang difference between Baerwaald and Stephenson is less than 4mm.
The offset angle difference is minimal, and given the variance in cartridges’ cantilever alignment, the stars might just align and result in your having a cartridge whose body is "square" to the headshell ... or not. IOW, I don’t view twisting a cartridge mount to be a big deal.
You might find it entertaining to download the John Ellison spreadsheet on the Enjoy the Music website (I maintain a link on my main support page to it) and look at the distortion numbers generated as well as the geometric parameters.
Personally, I look at the Stephenson approach (optimizing for the inner groove at the expense of increased average distortion) to be less preferable than Baerwaald, but everyone is different, which is why I agree with Raul’s advice to play and see what works for you.
As far as Stephenson and optimizing symphonic playback is concerned (i.e. it's all about the crescendo at the end of the record), I view this in the same way that I view people who don't play half of their records because they don't sound good.
Why would you sacrifice the delicate section(s) over the bulk of the record to improve the last part?
This is somewhat like a mother saying to her kids: "finish those terrible tasting peas on your plate, and then you get to have dessert". I'd rather cook vegetables that my kid likes ;-)
Cheers,
Thom @ Galibier Design
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That's a good point about 7" records. They're a bit off my radar.
Funny thing is, that I've not seen anyone develop math around smaller formats. Stevenson would likely be the closest to an ideal alignment.
Frankly, I don't find distortion increasing across the record with Baerwald, so if I started collecting 45's, I'd likely stick with it - only because I'm not going to get out the protractor for every record ;-)
Cheers,
Thom @ Galibier
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Hi Lew,
I was basing my comments on the fact cartridges are not perfectly manufactured, and the more expensive ones are by no means immune to this. They very frequently have cantilevers that are misaligned to some degree (not perpendicular to the two mounting screws holes).
So, you’re frequently twisting the cartridge in the headshell to achieve an alignment with any geometry you choose.
One’s altered alignment could have the effect of "fixing" this square-ness relative to some reference point on the headshell or alternatively making it worse.
Ultimately however, I think this goes to the greater point - that one’s preference for a distortion profile of a particular alignment will be more noticeable to the listener than any potential stray resonances resulting from going off the reservation by choosing an alternate alignment.
I just don’t know how one could separate all of the variables to test the stray resonance hypothesis, so in the end, it becomes a try it and see (different alignments) sort of thing.
I’ve been wrong before, and by no means am stating gospel here, but regarding your hypothesis, one could argue that a slight additional skewing of a cartridge (we’re talking a fraction of a degree) could break up standing waves.
I just ran through the Ellison spreadsheet (I only have Baerwaald and Loefgren sheets set up - not Stephenson). I hate to call anything trivial, but in this example, we're looking at an offset angle difference of 0.0402 degree difference between the two alignments.
I worked off the assumption that anyone doing this has a fixed mount armboard - that they cannot change the pivot to spindle distance, so this will be held constant. Here's how the numbers play out for a tonearm with a nominal 250mm effective length:
Baerwaald:
Pivot-spindle: 233.0331 (held constant)
Effective length: 249.5657
Overhang: 16.5326
Offset angle: 21.9891
Loefgren:
Pivot-spindle: 233.0331 (held constant)
Effective length: 250.0000
Overhang: 16.9669
Offset angle: 21.9489
Cheers,
Thom @ Galibier Design
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I'm generally in the same camp as Lewm on this one: I align the
cartridges based on the alignment the tonearm was designed for. Since
most of my tonearms use removable head shells and were designed for a
52mm distance from the head shell connection to the stylus, this has the
added benefit that the cartridge needs minimal if any realigning when
put into another tonearm.
I may be missing something here. I've had a long night on my CAD software and I'm a bit dimensionally challenged at the moment. If you have two tonearms using universal headshells: - Tonearm-A with
effective length A
and cartridge-A: the tonearm is designed for Baerwaald and this cartridge/headshell is aligned for Baerwaald
- Tonearm-B
with effective length B
and cartridge-B: the tonearm is designed for Stevenson and aligned as such.
If you swap the cartridge-B/headshell-B combo over to tonearm-A, you would absolutely need to perform a new alignment. I guess I don't get the concept of minimal realignment. It either needs a new setup (alignment) or it doesn't. Even if both arms were aligned for the same geometry (e.g. Baerwaald), the different effective lengths would mandate a different offset angle.. The whole concept of effective length is a dangerous one, because, two tonearms specified (for example) to have an effective length of 250mm would have different pivot-spindle specifications if one was intended for Stevenson or Loefgren and the other for Baerwaald.
I'm having problems visualizing any scenario where you could make any cross arm swapping work, but I'll ponder this one ;-)
Cheers, Thom @ Galibier Design |
If the cartridge is aligned as designed by manufacturer, then the
cartridge is straight in the headshell. Now move it another tonearm and
align it according to that tonearm’s design: it will again be straight
in the headshell. To the extent that the tonearms are designed to have
different offset angles, those are manifest in the arm tube. So the only
thing that could change then is how far in the headshell the cartridge
is. But if both tonearms are designed to have the stylus 52mm from the
tonearm connection, that doesn’t change either.
If you have
difficulty visualizing this, then visualize moving an SPU from one
tonearm to another. This is just replicating that with a normal
cartridge & headshell.
This makes perfect sense, now that I'm awake, Sampsa55, with (of course) the key element being the offset angle being built into the "bent" portion of the arm wand. I haven't thought too much about vintage tonearms in the last year, and frankly, I lost track of the 52mm standard, forward offset which is the other key element which allows this to work. Cheers, Thom @ Galibier Design |
Hi Lew,
I get that Stevenson has a significantly higher offset angle difference from (for example) Baerwaald than Baerwald does to Loefgren. Re-reading my earlier post, I didn't make that clear.
I'll file this away for future experimentation, but know that my preference for Baerwaald over Stevenson is such that the effect you've observed would have to be significant to drive me to revert to Stevenson on such an arm.
Is it possible? Sure, and I'm always ready for a surprise.
Cheers,
Thom @ Galibier Design
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Hi Chakster,
I'm with Raul - that if this concerns you, that you should experiment. Even Lew stated that he felt uncomfortable about generalizing his resonance experiment across other tonearms.
Cheers,
Thom @ Galibier Design
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Something just occurred to me: Is the offset angle required for Stevenson much more acute than that which is required for Lofgren and Baerwald? I think it’s the opposite, because of the aforementioned need to twist the cartridge inward on a Stevenson tonearm aligned for L or B. This would mean that there is more skating force at the null points with these latter two geometries, compared to Stevenson. That would be a point in favor of Stevenson. Just a thought. I’m not sure, but I believe so (Stevenson = more acute). Last night, I looked a bit more deeply into the Elison spreadsheet. The values for cells F3 and G3 are looked up in columns W & X. I believe you need to generate a set of Stevenson figures for these two columns. My Excel chops are a bit rusty, but this much is apparent. If anyone knows the answer to this, I'd appreciate it. It might be time to contact John. Darn you Lew! ... I have so much on my plate and yet this topic is really gnawing at me ;-) Cheers, Thom @ Galibier Design |
What is truly amazing with Victor X1 is my new 100k ohm resistors that completely change the sound of this cartridge. Hard to believe i’m listening to the same phono stage and the same cart i used before at 47k ohms. Hi Chakster, Subtle differences in damping; whether mechanical (from varying tracking force, anti-skate or application of damping fluid) or electrical (loading) can have a profound effect. Loading is about more than tuning the response peak although this is definitely important and dependent on your phono stage. Hi Lew - One reason I’m not inclined to take others’ experimental results at face value is because of small variances like what Chakster observed which tend to be overlooked. I’ve been guilty of this in the past as well. Setup parameters are another point of vulnerability. Since I’m in turntable development at the moment, one of my rigs goes unplayed for 2-3 weeks at a time. I find that when I fire it up, some fine tuning of the setup is necessary - specifically, parameters prone to be affected by suspension changes: azimuth, VTA and to a lesser extent, tracking force. Note that I don’t do anything until the cartridge has run for a few hours. IOW, this isn’t a result of the cartridge being "cold". Cartridges with line contact styli are more variable in this regard, although conicals are not exempt. I still want to ween you off that Feickert protractor ;-) It’s a good tool, but I don’t think you can achieve results repeatable enough to base your conclusions on. His software is great, but nothing in my experience has produced the precision and repeatability of an arc protractor and without this, I don’t think one can draw any meaningful conclusions. Cheers, Thom @ Galibier Design |
Hi Raul,
I agree with you that a tonearm manufacturer should provide an alignment tool with their product. It’s in their best interest that the customer have the best chance of achieving a good setup.
Lew -
An arc protractor can get you to within .001" of tracing the arc - limited only by your patience. I had forgotten about Conrad’s site. I’ve never tested it against the ones I produce with my CAD software.
As noted above, an arc protractor is specific to a single tonearm effective length, and you now have a website that will generate a protractor for you. If your printer takes card stock paper, you’re all set.
I stopped following the "other" protractor thread when the manufacturer refused to reveal his chosen alignment. It’s his choice and I respect that, but at the same time it leaves me no way of validating the accuracy and REPEATABILITY of adjustments made using his tool.
Parenthetically, I might add that I’ve seen some very good setups done with a Feickert. My preference for an arc protractor is that it eliminates any and all ambiguity.
If you think about any tool which depends on your siting down your cantilever at one or two spots, you’ll realize that the manner in which an arc protractor magnifies pivot-spindle/overhang errors lends a dramatically higher level of precision and it does matter.
For sake of argument, let's assume you have a 0.5mm overhang error in your setup. If you rotated your arc protractor so that you can land the stylus on the inner (lead out) side of the arc, and and (without rotating the protractor) you swing the arm over the lead-in (outer) side of the arc the stylus will be several mm from the arc.
This is can be confusing when someone is first learning how to use an arc protractor because they think they may have a 2, 3, or 4 mm overhang error. Once you understand this "error magnification" however, it is a huge benefit in terms of enabling precision adjustments.
If forced to choose, I would opt for getting one tonearm/cart set up perfectly rather than taking a buckshot approach of multiple tonearms with suboptimal tools. Yes, I appreciate the fun of playing with multiple arms, but I’m a patient guy and would rather get one thing right than many things wrong.
Cheers,
Thom @ Galibier Design
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