Regarding SRA and the adjustment to meet the cutting angle of a given record. ...
This was widely done in the late 1980ies first among the initial collectors of the audiophile quality early stereo records (DECCA SXL, Mercury SR, RCA LSC, EMI ......).
The difference in a 9-10" tonearm "relative height" ( or resulting SRA...) between the cutting angles of say a modern day Opus3 and a 1959 Mercury or EMI ASD/SAX were 1/2" (12-13 mm).
I am serious - these are not marginals.
The differences are huge.
Widely - if sadly .. - neglected and forgotten by todays audio writers and magazines.
God - as well as the tiny devil - lives in the details. |
Oops. "There's no on-the-fly..." nt |
There's on-the-fly arm height adjustment so it'll be set it and forget it once things are dialed in, just as I'm doing now. I understand the merits of adjusting for the various record thicknesses to keep SRA near optimum but I guess I'm not serious enough about this to make it a priority. Now if a tone arm manufacturer came up with a way to have preset arm heights available with the click of a handy dial, and still maintain the structural rigidity of the arm assembly, then I might be interested.
I'm going to try to measure cantilever angle just for shits and grins, and I'll be very careful so as not to end up just saying 'shit'. The idea of using a photograph to measure the angle is worthy since I'd have to fabricate some type of gauge otherwise. Digital images are a snap to take and process.
But I should probably just abandon the whole notion of using cantilever angle as an alignment parameter. Obviously it isn't something anyone is using and you've been kindly dissuading me of the idea from the start. '-)
Tom |
Tom, I always wondered exactly HOW people (who cared to ;-) actually measured cantilever angle. One dare not risk damage to the cartridge by trying to put an instrument of some kind near the delicate cantilever mechanism while the stylus is resting in a groove - yikes!!
I guess one could take a macro picture using a telephoto lens (to minimize parallax error) and then measure the angle from the photo. But it seems like a lot of effort just to obtain anecdotal (read: useless ;-) information.
Sounds like you'll be ready to go once your new TA arrives. Take all the time necessary for you to feel confident you've zeroed in on the best VTF setting, before going on to establish the vertical SRA point. Do not worry that later, dialing-in the VTF just a little better (like even as much as +/- 0.1 gm) is going to screw up your SRA setting. Why? Because it won't affect it up anywhere near the amount a slightly different record thickness or slightly different cutting angle (as favored by various lathe operators) will. I already stated that SRA can't be an absolute for those reasons -- so don't sweat it. Just get it in the 1.4 degree ballpark and then (hopefully) your new TA has 'on the fly' tonearm height adjustment so you can adjust the SRA slightly for each recording. One of our members, dougdeacon, does that all the time using his Triplanar arm. He even notes the correct arm setting on each record!
. |
First things first...
Well, Neil, I have well over 200 hours now on the cartridge so it's settled in nicely. (Much better term, I agree.) It sounds quite good right now but I won't try your installation protocol until the new tone arm arrives.
And regarding the VTF/SRA interaction, I may go ahead and measure the cantilever angle (WCA) of the current VTF and SRA settings and then use it (WCA) when I first install the cartridge on the new tone arm to set VTF and SRA. I'll just play records for a while and get to know the sound. Then, after using your recommended cartridge alignment protocol and things are sounding about the best they'll be, I'll measure the cantilever angle and compare the before and after WCA settings. Just for kicks.
Thanks again to you and D. for the opportunity to learn a thing or two about cartridges and setup.
Tom |
Nsgarch, while I agree with you regarding the vast majority of custom MCs and their behavior, let me briefly add, that the 3 MC mentioned by me are quite different in their mechanical parameters.
The Ortofon is indeed asking for 3.5 + grams VTF, but the EMT and FR-7 are around 2.2 and 2.6 respectively.
The EMT isn't all that low compliance and has a lifespan of less than 3 years in use.
The dynamic compliance of the FR-7 and SPU is around 7-9, but indeed mark the low bottom of the range.
These 3 cartridges do perform to specs right out of the box NOT because of certain extreme mechanical parameters, but because they were designed and made to do so - as they had to meet broadcast (read: professional) standards.
While I agree that the SPU and EMT may not be up to full modern day standards in terms of overall sonic balance, I (...well known by now...) still have to mention, that no today cartridge is up to the overall sonic performance of the more refined versions of the FR-7.
I have mounted, aligned and heard extensively EVERY top-flight cartridge of the past 3 decades - with every top tonearm you name and in high-priced and quite sophisticated set-ups.
Very low output brings back the topic of high class matching SUT......... |
Dertonarm, I never question the reports of others' personal experience(s) except in those (extremely rare) instances when I've had the same experiences only with quite different outcomes ;-)
I also think people need to be careful when assuming certain cause-effect relationships; and that they are responsible for the things they observe.
Because you observe that some cartridges you've worked with perform to spec right out of the box, doesn't disprove my assertion that there is a change, over time, in the elastomers; which there most definitely is, even in modern suspension materials, and especially for the cartridges you mention.
Most new (or even old) MC cartridges, unless they're defective, will perform "within a very narrow window within specs", as you put it, at a variety of loads and VTF settings. So what? I can easily make a brand new cartridge sound 100 hours old by loading it too high and applying a bit more VTF which will increase frequency response at the top and bottom until the suspension limbers up. I choose not to do that however knowing I'm going to have to do it all over again in 100 hours ;-) And because I enjoy hearing a cartridge going through its changes.
None of the three cartridges you mention are typical MC cartridges. They ALL have extremely LOW compliance, even for a MC (5 as opposed to 30 for most MC cartridges) and they all have HIGH VTF specs (3.5 to 9 grams!, as opposed to 2 grams for most MC cartridges.) So it's unlikely you'd hear any performance difference between brand new and 100 hours old, with any of those cartridges. In addition, those three cartridges are very low output and IMO not up to current performance standards ;-)
. |
Nsgarch, there are indeed only very few cartridge featuring a suspension which does need little to no time at all to "settle" or "break in".
To name the very few:
EMT, Fidelity Research FR-7, broadcast version of Ortofon SPU.
All these do have in common, that they were designed and initially made for broadcast use. Means they need to give 100% performance right out of the box.
And thats what they do.
Let me add further, that at least the FR-7 series does feature a very unusual suspension indeed. To this day, I have not found a single FR-7 cartridge which does not perform to specs. The last production run was 25 years ago. I have had over 3 dozen samples of this cartridge-family gone through my hands. All performed within a very narrow window within specs. Outlasting every other cartridge.
Worth mention I think.
So high performance can go hand in hand with extreme durability and 100% out of the box.
My 2nd back-up cartridge has by now the 4th stylus since 1988. Still running and sounding the very same way it did 2 decades ago.
The EMTs suspension however won't last a fraction of that time. |
Tom, you have the sequence reversed. There should be no tail-chasing ;-) ! You first MUST wait 50 hours (100 if you can stand it) until the suspension is settled in; a term I prefer to broken(!?) in ;-)
And forget some manufacturers' claims (like Immutable Music who made my Transfiguration for instance) about their new "space-age" suspension elastics. Maybe they ARE less susceptible to deterioration, however, there are NO supensions/cartridges that I've so far used, or more broadly, heard about or read about from their users, that didn't change quite audibly after the first 50 - 100 hours. Which is another reason why running-in a new cartridge at .25 grams OVER the max. recommended VTF (as I described earlier) for the first 50 - 100 hours is IMO essential for the long term stability of all other settings, including SRA.
The sequence I recommend (to avoid tail-chasing) is:
1.) Install your new cartridge in the TA and make the various geometrical settings as reasonably accurate as possible without being obsessive about it (there will be plenty of time for obsession later on ;-)
2.) Set the VTF to .25 grams over the max. recommended, for the first 100 hours.
3.) Play records for 100 hours. You don't HAVE to listen to them, but definitely play them. I emphasize that because some folks think you can "season" a suspension by just leaving the stylus/arm/cartridge sitting on a record for 100 hours without the platter revolving. I don't know about that one, but it just doesn't feel right to me!
4.) After the initial 100 hours, re-set the VTF for the loudest output. Let the high frequencies be your guide for "loudest", because they are the first to disappear when the coil isn't in the perfect position. You may have to do a few trials before you can decide. Use a mono record as I described earlier. That setting should be good for a long, long, time.
5.) Set the SRA as I described elsewhere.
6.) Level the platter using a small spirit level. Check with the level oriented in opposite directins. Average if you have a crappy level. Then, make sure the headshell is level along the spindle-to-stylus line.
7.) Set the azimuth (if your headshell or tonearm tube allows) using the mono record technique.
8.) Check stylus overhang and cartridge off-set settings from Step 1. But FIRST, note your VTF, because if the overhang needs more than 1 mm adjustment fore or aft, you'll need to reset the VTF to what it was before you reset the overhang.
9.) Set the anti-skate to ,3 to .5 times the VTF as a start. Line contact styli produce so little frictioon in the groove that using any anti-skate is probably gratuitous as far as differences in sonics is concerned -- but it does tame the TA skidding toward the spindle at the mopst inopportune moments!
10.) Set the loading (for MC cartridges) starting at 15 times the cartridge's internal impedance, and raising it slowly until the bass 'tightens up', but before it diminishes any amount in volume; and before the treble gets glaring (the bass will usually go first though.) If your phono preamp has only fixed load settings, 100 ohms will usually work very well for most MC's.
. |
Excellent, Neil! One of the better descriptions of the construction and workings of a moving coil cartridge that I've read. And to you and D: Now I understand that the idea of using WCA is truely "wishful thinking".
Guess I'll have to make the investment in a quality magnifying scope and spot lighting in order to more accurately set SRA. I have extraordinary near vision and can see the stylus angle fairly well, but it makes sense to start from a known setting.
However, the relationship of SRA to VTF and optimal coil position makes the whole vertical alignment process a bit of a "chasing-your-tail" scenario. Set for SRA and then fine-tune VTF for optimal coil position (best sound); but then you may have altered SRA. Reset SRA; but then you may have altered the coil position and have to fine-tune VTF again. And on it goes.
I was hoping for an easier way to find the vertical alignment sweet spot. I wish. :-)
Tom |
I wish I could agree with more of what everyone is saying, but most of it is wishful thinking. For instance I assume that the stylus is properly mounted to the cantilever and that the manufacturer knows the angle of the cantilever when the stylus is at an optimal rake angle. Wouldn't it be much easier to measure the angle of the cantilever rather than a tiny stylus? All I can say is I wish it were true but it's not. It's hard enough to mount a stylus to a cantilever. Expecting to mount the diamond at the same angle to the cantilever time after time is simply not possible. Even the solid one-piece diamond stylus/cantilever cannot be fabricated identically time after time. Thus the need for calibrating the initial zero SRA point for each stylus-cantilever assembly. Thaough statistically possible, no two can ever be assumed to be the same. As for Well, the cartridge manufacturers do already provide the parameter to set the VTF right: - their recommendation of the range the VTF have to be set in.
There's a reason for specifying a 'range' and it's this: there is only one VTF setting for an individual cartridge at which the suspension will compress just the right amount to place the coils at exactly 90 deg. to the magnetic force field. If you look at a mechanical drawing or exploded view of a typical MC cartridge, there is a tension wire attached to the coil armature on the opposite (back) side from where the cantilever is attached. This wire is carefully pulled to a certain tension and locked with a set screw. This "pre-compresses" the suspension rubber; otherwise applying the correct VTF would just collapse the suspension and the cantilever would 'retract' up into the cartridge body ;-) Further, that wire is not pulled straight back, but slightly upward and back, forcing the coil armature to sort of 'tilt' forward and putting a little "downward English" on the cantilever - then, when the stylus contacts the record at the 'perfect' VTF, the suspension compresses and the coil armature tilts backward slightly, bringing it into proper right angle relationship to the force field. It's the trickiest of all the steps in making a cartridge and each cartridge will have a specific VTF setting (within its specified VTF range) where that alignment is correct. As far as I'm concerned, each cartridge has one absolute VTF setting at which this perfect alignment occurs. (It also happens to be the one where the cartridge sounds its best ;-) The SRA setting is not absolute. It will vary +/- a half a degree from the average 1.4 degrees as a result of two factors out of our control: record thickness and the whims of the lathe operator. Which is why SRA on the fly tonearms are preferable. And why I'll either eventually sell my SME V or get so old I just don't give a rat's a-- anymore! Then you have to get the other geometries right on the money. Overhang, offset angle, azimuth. The only setup parameter that will usually vary (SLIGHTLY) from the theoretical ideal, and therefore a bit open to musical "taste" is cartridge loading. That variability is due to differences in tonearm mass/damping, cables, phono preamps and/or SUT's, or other room and/or hardware factors. It's where you get to tailor (if only slightly) the sound of your cartridge to suit your sonic preferences. The other settings are pretty much absolute if you take the time to discover them. One can't (or shouldn't!) just go and "de-tune" a cartridge in an effort to change its sound ;-). You can try fooling with loading, cables, pre-preamp equipment, even different tonearms; but finally, if you don't dig the sound, it's just not the cartridge for you. . |
Well, the cartridge manufacturers do already provide the parameter to set the VTF right: - their recommendation of the range the VTF have to be set in.
We will get no more and there is good reason why.
Aside that there is no monetary reason for the cartridge manufacturer to add any mechanical "helpers" - there too is little need.
Analog cartridges for the high-end customer is a luxury market with highly emotional customers. Nothing to quantify - nothing to determine the quality with any measurable parameters.
Similar to high-priced jewelry (at least there are quantifications like purity of precious metal, carat etc.), high performance cars - you name it.
Its individually viewed AND judged performance and personal preferences.
I guess - as frustrating as this might look on first sight to some - that we are doing quite well the way it is now.
Unfortunately this means that setting up an individual analog cartridge to fully show its abilities will always require skill, knowledge, experience and very precise handwork.
But then most of these are needed in all real passions.
There is hardly ever any free lunch out there.
Cheers,
D.
We all agree that a cartridge usually needs some time to reach its designed for operating conditions (velocity). Furthermore we are looking at a bundle of other depending parameters (tonearm, cable, matching impedances, inductances etc.) in interaction with the cartridge and thus influencing its sonic performance.
Next in line is individual sample differences within a production design.
No two cartridges of a given production design are truly identical in the technical sense nor in their technical parameters.
After all most are hand-trimmed or fine-tuned and so they are similar and go for a similar "family"-sound, but are not identical.
We will always need a range to work within. |
Neil, thanks for the explanation. And for being tolerant of my misunderstanding of the relationship of the cantilever and generator. (The few schematics I've been able to find are crude representations at best.)
My original thought on the use of cantilever angle had more to do with setting proper stylus rake angle, as installed by the manufacturer. Using SRA as a measurement parameter is possible but not easily measured. Your procedure is certainly an improvement but still requires more effort than many vinyl lovers are willing to undertake. I wanted something quick and easy. :-)
In considering the use of cantilever angle, I assume that the stylus is properly mounted to the cantilever and that the manufacturer knows the angle of the cantilever when the stylus is at an optimal rake angle. Wouldn't it be much easier to measure the angle of the cantilever rather than a tiny stylus? (The exceptions you mention, notwithstanding.) If the process of mounting the stylus to the cantilever is not consistent and the resulting placement is so variable that determining proper SRA is not possible using WCA then this whole idea is a lost cause.
Tom
PS: We may agree on one thing: VTA is a fairly useless parameter. '-) I only included it as part of the collective theme of cartridge alignment. |
Tom -- finding true vertical for a line or micro-ridge stylus, as I outlined, is actually quite easy, and many people have done it with great results once it was explained. And there are only three stylus geometries, if what you mean by "geometries" is stylus 'shapes'. There are: spherical, elliptical, and line/micro. There was also the Shibata which was an attempt at making a line-contact but before laser cutting techniques were available. After finding zero SRA, it's nice but not mandatory, to have an arm with vertical height adjustment "on the fly" (while the record is playing) so you can experiment easily once you know where true vertical is for your stylus. As for your statement I refer to it as Weighted Cantilever Angle (WCA) which is the angle of the cantilever (from horizontal) where the manufacturer intended the cantilever to be positioned within the cartridge generator. I think you are using the wrong terms, which is what's getting you into conceptual trouble. It's not the CANTILEVER which is positioned WITHIN the generator -- since the GENERATOR consists of the coil/armature positioned inside the magnetic field. The cantilever is completely outside that area. And frankly, I don't think cartridge makers are much concerned with cantilever angle, so long as it allows the cartridge body and front pole piece to clear the record surface. What cartridge makers ARE interested in doing is making the cantilever as SHORT as possible to eliminate resonances. The van den Hul Colibri doesn't even HAVE a front pole piece in order to facilitate an EXTREMELY SHORT cantilever. And DECCA cartridges have no cantilever whatsoever! I truly wish people would stop using that "SRA/VTA" term as if they are the same thing -- THEY ARE NOT!! Further, VTA can be pretty much any angle between too low (the back of the cartridge hitting the record) and too high (the front of the cartridge or front pole piece hitting the record) and so what!? What IS important, is to let the VTA chip fall where it may, while instead MAKING SURE the stylus' edges slant forward at exactly the same angle as the forward-slanting groove undulations - thus locking them together. Sorry for the long post but I'm afraid we have little to agree on at the moment ;-) Neil . |
Hi, Nsgarch, the use of weighted cantilever angle would not add to the confusion but rather eliminate the use of SRA/VTA since both of these alignment parameters are nearly impossible to measure, especially VTA. Your description of how to find optimal SRA is, unfortunately, unrealisitic when considering the range of stylus geometries and the need for high magnification to actually see the stylus.
We actually agree on several aspects of cartridge alignment and your comments reinforce my belief that we need a more simple and easily measured parameter.
Tom |
Hi, D., your comments reflect the factors that I, too, believe (but don't ascribe to) will keep consumers from having an easily measured parameter for cartridge setup. My thoughts (rebuttals really) on the points against using WCA follow:
1) "...cartridges suspension hasn't adapt to ambient conditions and hasn't reach its full velocity yet, the idea of the "WCA" won't give the right result."
This is, in some ways, a mute point. Cartridge break-in, controversial as it may be, should not be a factor in alignment. My opinion is that we should just play records for some time before we seriously attempt to fine tune cartridge alignment.
2) "Next problem is, that the cartridge designers won't supply any such thing."
Probably not, at first. But I believe that cartridge manufacturers might be willing to provide this information for LOMC cartridges above a certain price point, say $750 to $1000 USD for example. It's in their best interest. If their cartridges are so good, why don't they publish the design parameters? Competition can be a good thing.
3) "...fear that this would arise even more questions by the customer."
Not necessarily a bad thing; assuming that WCA is only provided for audiophile cartridges (see #2 above), consumers would begin to ask why manufacturers are unwilling to provide WCA specifications. Audiophile cartridges are intended for a more knowledgable and experienced consumer. Again, competition can be a good thing.
4) "Todays cartridges - especially the Top-flight ones - do not feature any such thing."
And why not? If a manufacturer claims that their "top-flight" cartridges are so good, they should be more than willing to provide the specifications, including WCA, for their best cartridges. Manufacturers provide a range for VTF, why not for WCA? No shame in acknowledging the variability in suspension parameters.
5) "...setting the "right" "WCA" can be performed by looking through a highly illuminated magnifier from the front into the body of the cartridge..."
That's one of the biggest problems: The need to use high magnification and illumination in order to more accurately establish proper cartridge alignment. Many experts espouse the benefits of using these techniques to find the optimal alignment of SRA or VTA (impossible without x-ray vision). Much too complicated and inconvenient. WCA would allow a much more convenient parameter for consistent measurement and alignment.
And lastly...
"But so far we are left in the dark and have to trust our ears...."
That's the conundrum. Why should consumers be "left in the dark" in regards to optimal cartridge settings. If a customer is willing to spend a thousand dollars (USD) or more for a product that has a limited lifespan, the customer should be provided as much information as needed to get the most enjoyment out of the product without needless uncertainty and undue complications. Adjusting "by ear" is a poor reflection on the nature of cartridge installation. Most speaker manufacturers have much more objective parameters in setting up their product for optimal performance. And listening environments are far more variable than the plinth/tone arm/phono stage environment in which cartridges are installed.
Cartridge alignment should not be the mysterious endeavor that seems to be perpetuated by audiophiles and enforced by manufacturers. It needn't be so darned complicated. Using weighted cantilever angle (WCA) to find the (nearly) optimal alignment could make cartridge installation so much more convenient and consistent.
Tom |
"WCA"? Do we really need another acronym? What you appear to be talking about is finding the VTF (within the manufacturer's prescribed range) which will put the plane of the coil windings (basically the plane of the coil former) at a right angle to the lines of the magnetic force field generated between (or 'around', depending on the design of cartridge's magnetic generator) the magnetic pole(s). (In the case of MM cartridges, it's the reverse.) The easiest way to determine this is to listen for or to measure (your ear will work just fine) the cartridge's maximum output at two or three nearby VTF settings (before making other adjustments.) Some tips: 1.) Do this with a mono record and (if it has one) your preamp set on 'mono'. Why? You may have harmonic distortion or minor tracking issues at this point before setting all the other parameters - but it's still important to set this one FIRST! 2.) If your cartridge is a new MC, delay all but a rough setup until after a minimum of 50 hours, AND for that first 50 hours, set the VTF to 1/4 gram OVER the manufacturer's recommended maximum. Why? First don't worry; you won't hurt the cartridge or the suspension running the VTF a bit high (and you should own an accurate digital scale by now ;-) This will result in a suspension (when break-in is over) with a 'Q' (elasticity factor) that remains constant just BEYOND the normal operating range -- otherwise, the 'Q' can be non-linear just at the point most MC cartridges yield their best output (the high end of the VTF range.) After doing this, you can move on to setting the SRA and other alignment parameters; EXCEPT: forget VTA, which, if you give it a minute's thought, you'll realize is a totally useless concept. If everyone's cartridge's dimensions and angles (ALL of them!) happened to match EXACTLY all ALL of the cutter-head's dimensions and angles, there might be a case made -- and even then it would be philosophical at best, because you could only reliably play records made with THAT cutter-head/operator! And besides, lathe operators make adjustments too!! And cutter-heads generally are cantilever/suspension-less! AND, if you have a stylus with a spherical or elliptical tip, you needn't worry too much because how it fits in the groove is pretty much the same over a range of SRA. A micro-ridge or line-contact stylus is just the opposite and SRA is extremely important. Here is the most accurate way to do it I've found to do it: Basically, you have to find the point (after finding/setting the optimum VTF) at which the stylus is perfectly vertical in the groove (looking from the side, not the front.) This is different for every cartridge (even among the same model/manufacturer.) Once you've found that baseline, you can go from there. I've provided detailed instructions here: http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1140840022&openmine&zzNsgarch&4&5#Nsgarch. |
Hi Tom, the big problem is, that this will not work with a cartridge not fully broken in yet.......
Unless the cartridges suspension hasn't adapt to ambient conditions and hasn't reach its full velocity yet, the idea of the "WCA" won't give the right result.
Next problem is, that the cartridge designers won't supply any such thing.
It would force them to work even more precise and will give them no further USP if they incorporate such a "helping hand".
I guess most would fear that this would arise even more questions by the customer.
There have been designs in the past which did perform 100% right out of the box with very little to none variation in velocity.
Mainly cartridges designed and sold for broadcast (EMT, Ortofon SPU, Fidelity Research FR-7 series, Supex).
The better of these (FR, Supex) do feature a suspension which does keep its velocity from day one for over 30 years.
Todays cartridges - especially the Top-flight ones - do not feature any such thing.
In general setting the "right" "WCA" can be performed by looking through a highly illuminated magnifier from the front into the body of the cartridge and see, whether the cantilevers diameter is center in the yoke.
This however can't be seen on all cartridges - but on many.
But even this would only give a momentary result - changing in case the cart isn't broken-in yet.
There is no free lunch - it is still a game with a wide selection of important parameters which all need attention and skill to fine-tune.
If cartridge designers could agree upon strict mechanical parameters for all cartridges - that would make such optical settings much easier.
But so far we are left in the dark and have to trust our ears..... |
