Just wanted to add, the suggested Spindle-Pivot distance for the AQ PT-8 Arm is supposed to be 211mm. Mark
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Thanks for the info so far.
The info I have downloaded, and know so far, is a claim of the AQ PT-6 through PT-9 on Vinyl Engine of an effective length of 229mm, mounting distance of 211mm, overhang 18mm. All show null points (Baerwald) at 66.0mm-121.0mm
As has been explained to me, some of these arms were indeed like you say, mounted at 210mm, and perhaps the specific reason, was that one wouldn't run out of Headshell Slots, wouldn't need the Cartridge mounted so far to the end of Slot travel, and have the Cartridge more centrally mounted in the Slots? Just a thought?
To achieve Baerwald alignment with my Turntable Basics Mirror Protractor, and ZYX Airy 3X, I'm just about at the end of the Slot's travel, but can achieve what appears to be dead on alignment with the TB Protractor.
It was like this as well with my Benz Glider, and in fact my previous Benz Glider literally fell apart last year in my hands in two pieces trying to shift it forward far enough when I used the TB Protractor. The Body seperated from the Base, and with it went the Pin Wiring, and Suspension Wire! One drop of Adhesive was all that held the two together, and after 10-11 years, maybe that Adhesive had gotten slightly weak? I didn't apply too much pressure, but was probably trying to shift the Cartridge forward where it just couldn't go due to running out of Slot on the Headshell.
Perhaps, VPI when they drilled the Plinth 12 years ago, did so every so slightly too far? Mark
Thank You Narrod, Another person has advised me exactly as you have, to perhaps trying Stevenson Geometry.
While my rig is sounding pretty darn good, I think all can sympathise, trying to squeeze every last bit of performance from my vinyl rig. My ZYX Airy 3X is still very young in age, certainly doesn't have sufficient break-in time on it yet, but sounds better, and better each time I play it.
I have been able to achieve dead on alignment with the TB protractor, and yet wonder, with these sight line protractors, and even though I've noted a 1mm error on mounting distance, is alignment still correct? I've used the outer grid to align, have aligned the stylus, and cantilever, not the body, and haven't concerned myself too much with the inner grid on the protractor.
I do get somewhat confused with protractor geometry (wasn"t the sharpest crayon in the box in match class) but gather that regardless of mounting distance, sighting with the sight line protractor "should" net me correct alignment?
If I am incorrect about this, I am hopeing somebody will correct my wrong assumptions. Thank you, Mark
Mark, I think that from your description of the issue you may just have to live with a small amount of error in the setup. In reality, we all do. The only thing we may be fortunate enough to do is limit that error more in one setup than some other setups. But it has been published in several places that an error of less than .5 mm is almost a necessity to get the most from a particular arm/cartridge. This doesn't mean that you won't still enjoy what you hear. Perhaps this is something to keep in mind if you ever go looking for a table upgrade.
Dan alludes to the active thread here:
http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1210959908&read&3&4& where you'll find several informative links.
Read this stuff and then read it again. Know that using a sight line introduces more error than it attempts to correct. I'm not arguing that you can't get "lucky" using a sight line, but we want to eliminate luck from the equation and introduce repeatability.
May I humbly comment that you don't know how good your setup can sound, and won't know until you set it up with an arc-style protractor which agrees with the pivot to spindle distance of your rig?
Know that you want to take your best shot at having a protractor to match your current pivot to spindle distance - as long as you have enough room in your headshell slots to accommodate corresponding effective length and offset angle changes.
So, if your actual p-s is 210, that's fine, as is 212. It's more important to know the distance as precisely as you can measure it. This assumes two things: (1) that you have headshell slots long enough to accommodate the new tonearm parameters, and (2) that if you mount the arm on another turntable that you replicate your current pivot to spindle distance.
Remember, the only down side of an arc style protractor is the effort you need to put into getting the pivot to spindle distance to agree with the protractor you've specified. The up side is huge however and worth the effort.
Unless you're using something like the trammel portion of a Feikert protractor, you will unlikely be able to measure your pivot to spindle distance to within .5mm.
So, try the following before you do anything else: loosen your tonearm mounting screws to see how much play you have - the ability to make fine adjustments to your pivot to spindle distance. You will likely find that you can get +/- at least .5 mm and perhaps more.
IIRC, your AQ arm mounts like a Linn, with three holes that fix a base plate in place. Know that you can enlarge these 3 holes (as well as the arm stub hole if necessary) slightly to get further fine adjustment of your pivot to spindle distance. Just remember to measure twice, and drill once.
No matter how you specify your protractor, you'll want to know what you're up against from a p-s distance perspective anyway, so you might as well know now rather than later.
Be prepared for a revelation when you get everything right.
Thom @ Galibier
A quick follow-up on the Feickert protractor ...
In my above comments, I was endorsing it as a reliable (albeit expensive) means of measuring pivot to spindle distance and nothing more.
I have not played with this protractor, but people whom I trust tell me that it yields quite a different alignment from those achieved by both the Wally and Mintlp protractors (Baerwaald).
Thom @ Galibier
Just wanted to follow up here, what my findings were, and I hope my post isn't too long, or bores anyone.
Ken Willis very kindly forwarded me some Arc Protractors to try, both Baerwald, and Stevenson Geometry at 211mm, and 212mm.
Clearly determining that my AQ Arm-Spindle Distance was indeed 212mm, I tried the 212mm Baerwald, and had found that my previous alignment with the Turntable Basics Mirror Protractor was right on the money as far as Cartridge Overhand was concerned, but did quickly notice a very small error-discrepancy with Cartridge Zenith Angle, which was off slightly.
It appears that I have no problems attaining alignment at 212mm with Baerwald, the Stylus is dead on in the little reference circle.
And I know the reason why this was, read on.
When I first installed my ZYX Airy 3X, and aligned with the TB Tractor, I didn't really snug the Cartridge Screws that tightly. I knew previously from all the good reads from you smart folks here, that one isnt supposed to lay on the Screw Torque with Gorilla-like pressure, and being that the Finger Lift for the Arm is a seperate, individual piece at the top of the Headshell, in which the Cartridge Screws actually pass through, and then on to the Cartridge, by moving the Arm from its rest everything you play an LP, the Cartridge must've have ever so slightly twisted sideways on the Headshell.
Another reason, I was perhaps afraid to over-tighten the ZYX Cartridge with its Acrylic Body, and had feared possible damage to the body by snugging the Screws too much.
So, I did succeed in snugging the screws a bit better, and all seems well, that my alignment looks to now be nuts on.
Of course, this was a print out, and only a paper protractor, and I'd like to comment about my findings with Protractors. The Turntable Basics Protractor is a great protractor, especially for the money, and I wholeheartedly thank Doug Deacon for suggesting this purchase. But what I do note with a Mirror Protractor, is difficulty in getting all lined up properly, due to difficulty in seeing everything.
As many of you have perhaps also found out, shining a light on a Mirror doesn't really light it up, and aid seeing the reference grid, and exact Null Points. I've tried back, front, side, and rear lighting with many different types of lights, and it seemed higher intensity did not aid the process, and some odd angle lighting seemed to proove best. With a white background though, the contrast seemed much better, and I could more quickly see any errors.
The TB Protractor is propbably not in any way inferior, just a bit harder to use because of this.
Since Ken Willis can make an Arc Protractor with geometries for up to four different Arms-Tables, I'm going to order a custom protractor ASAP, as I have another Table, a Denon with Grace Arm, and would like setting this Table up accurately as well.
It appears Ken is making some very nice protractors, as I have heard so far nothing but praise about what he's making. I understand Ken is a member here, but I cannot recall ever seeing him post here? I know he frequents Audio Asylum.
Perhaps when I get his "official" protractor, I'll comment again in a seperate thread, and perhaps even write a review as well.
Thank you all again folks very much, your help, and advice is deeply appreciated. Also again, many thanks to you Ken for your time, and help! Mark
Hello Thom, Thank you too for your comments, and support, your experience has helped me.
With my AQ PT-8 Arm, I am currently using a Pete Riggle VTAF, and as you probably know, the VTAF Bushing in essence replaces the Arm Mounting Base.
My Table is still essentially a HW-19jr, (But with 16lb MK-IV Platter/Bearing) with the stock one Piece MDF Plinth, and I had kicked around the idea over the past few months of replacing this Plinth with either a machined, solid 1" thick Aluminum Plinth, or 1" thick Black Acrylic Plinth.
Haven't yet decided if I'll ever do this, but having one friend who's a master machinist, constructing a 1" Alu Plinth wouldn't be a problem for him, and getting the precise P-S distance to whatever I choose.
Not sure how Aluminum would sound, but at about 18"x21", and 1" thick, estimated weight he claims would be close to about 25lbs. In this scenario, I could have the Plinth Polished-Black Anodized as well.
Cost is not cheap, but perhaps not as expensive as one would think. Sheet of Alu Stock would be about $100 shipped, and about another $100-$150 for machining, and Anodizing.
No doubt the stock Sorbo Suspension would be taxed, and another method-type of suspension would have to be implemented as well. Mark
One thing I've learned is that you can never predict the results of any change you're going to make. The changes need to be considered in the context of your complete analog ecosystem.
For example, yours (VPI in general) is one of the only cases where I've seen Sorbothene contriubite positively to the sound of a turntable. There may well be others, but I have not encountered them.
I'd be inclined to try to perform a root cause analyisis on what you like about the Sorbo - even if it's only empriically done (e.g. trying other stuff).
I'm wondering if you're responding positively to sorbothene's damping properties, or to the fact that it's sticky and holds thing in place. If you are able to answer this question, you might be able to take things to the next level (or not ... no guarantees in this blood sport).
If you decide to give aluminum a whirl, have your buddy get a quote on pricing before ordering.
Everything we buy these days is so dependent on fuel costs and prices jump around like soy beans futures these days (although in general, trending sharply upward).
Thom @ Galibier
Another suggestion: try installing your cartridge without the finger lift. The extra hardware and material boundaries make your cartridge less stable in the headshell and alter the resonance behavior of the cart/arm. I can't guarantee this ecology change (as Thom put it) will be an improvement, but I can guarantee you'll hear some differences. I'd bet in favor of leaving the lift off, but you can be the judge of that when you listen.
Hello Doug, thank you for chiming in, and it's good to see you back here posting some!
Was I'm sure hard for some of us folks "holding up the fort" so to speak, in your absence!
I will probably do as you wisely suggest, and remove, and put away the little Arm lift, as you once suggested to me to do many months ago. When Ken ships the new protractor, and I again check all parameters, and I will at that time remove the finger lift for good.
As you mentioned to me once, Frank Shroder leaves em off a $6K Arm, and there may be very good reason, due to sonic detriment, rather than also the obvious mechanical one that I had an issue with.
I'm generally not a guy who constantly lifts an Arm from track to track anymore, preferring to let an entire side play through. Thanks Doug/All Mark
I just purchased a wally tractor universal. On it is an arc for rega arms with an effective length of 239 mm. I have an origin live arm, the OL specs are spindle to pivot distance 223 mm and overhang 17.24 mm, effective length 240 mm. Being a newby do I then shoot for a spindle to pivot distance of 222 mm and use the 239 mm arc or aim for 223 mm P-S and use the 239 mm or another (241mm) arc?
You're more likely to be able to align a cartridge at the Baerwald points on an OL arm if you mount the arm somewhat closer than the specified 223mm. The problem with 223mm is that, (i) Rega/OL arms were not designed for Baerwald and, (ii) at OL's specified 223mm mounting distance most cartridges will be very near the ends of the headshell slots and some won't align properly even when slid all the way forward.
Here's what I'd do:
1. Mount the arm at 222 (the Rega-specified distance, which is presumably what Wally scribed his Rega arc for);
2. Mount the cartridge and see if you can get the stylus to hit the arc at all points by moving the cartridge forward or back in the headshell;
3. If you can trace the arc, bingo. Square it up on the alignment grids and your're done.
4. If you can't trace the arc, even with the cartridge all the way forward, you'll need to choose another arc and another mounting distance.
Part Deux,I went on today to check my mint Denon DP-2550, with Grace DA-307 Arm, S-P distance supposed to be 230mm, and evidently, the previous numb nuts mounted the Arm at 221mm Way off.
The furthest I can mount the Arm is at 228mm, so I have contacted ken, and see if a Protractor at 228mm, with nullpoints at 57.9mm/114.6mm is doable?
Not Baerwald, or Stevenson, but hopefully this will be the ticket to good sound from this very nice Table.
This is my "Quad Baby", set up with new AT-15S, and a NOS in box AT-20SLa on ice.
Just bought a spare AT20SS Stylus from LP Gear for the AT-20SLa, and understand it will fit the AT-15S as well. Ultra "skinny" Beryllium Cantilever! Looks beautiful!
Also grabbed one of those Black Nitrile "Tranquility" Belts for my VPI 19 Table, will put it on tonight, and give a listen with the ZYX Airy 3X. I'll probably be in the police logs tomorrow! Mark
Null points at 57.9/114.6 aren't necessary, and probably not optimal unless you have many LPs with very wide lead-in grooves (like 1/2" wide) and music cut right up to the label. Not very likely, so I don't understand why anyone would choose those weirdly positioned null points. They'll result in very high distortion on the first track and higher than necessary distortion in the middle.
If it were me I'd ask him for an arc designed for the Grace mounted at 228 with Baerwald null points.
You know something Doug, you are as sharp as a tack!
Please don't ever leave this group!
It seems Ken Willis also immediately knew this, as today, he cheerfully sent me for free, 4 pdfprintouts via email for Grace Specs at 227mm/228mm, and as well Baerwald Null for 227mm/228mm! Ken has realy been a sweetheart of a man for helping me through all this.
I'm sure glad you guys know something, as I'm so totally in the dark about this crazy geometry for Tonearms!
As soon as I can confirm what works best for the Denon, (as I've already seemed to determine that Baerwald at 212mm S-P for my AQ Arm works well), I will have Ken make me a permanent Arc Protractor for both Arms.
As Ken states, he can make "one" custom specified Arc protractor for up to four different Arm-Table Combinations. Or, make whatever a custom wants as well I presume.
Doug, I thank you again very much for the time you have taken here, and in private, as well as all the other helpful Agon Forumites for participating in this thread.
After I have Ken make my custom Protractor, and it is in hand, I will try to do a review here, and as well, post some pics of Ken's handiwork. Mark