Anti Skating Calibration on Dual 1229Q

[D_Canard]

I have a new-to-me Dual 1229Q which has quite a number of things wrong with it, mostly minor individually but cumulatively major.

In this thread I will talk about the mysteries of anti skating.

I have read that anti skating is very difficult to set up without a test record and an oscilloscope. And even then an optimum test record setting is probably only a best guess average for real life play using different records at different speeds.

I have neither a test record nor an oscilloscope so enough said here.

I do have my eyes and ears, though, and I can see and hear that there is something very wrong with the anti skating calibration of this 1229Q.

I have the tracking force set at a mechanical-balance-scale-measured 3 grams. (The calibration of the tracking weight dial scale on the tone arm is way off, too--I set if for 3 grams and then use the mechanical balance scale and counterweight to set it accurately to 3 grams.) I use mostly small bodied Stantons (500s) and Pickerings with a variety of different styli for playing 78s, 45s, microgroove LPs, and older LPs that skip on my way too highly compliant modern high-end turntable. 3 grams is a little light for 78s but it works. On my older Dual I used 4.5 grams.

If I set the anti-skating at 3 grams (on relevant scales), auto-start does not work reliably, the tone arm often throwing itself off the record, nor does auto stop-work properly (the tone arm skipping before it reaches the run out grooves or kicking back across the record once the arm starts to lift). At 3 grams of anti-skating, LP play is the least problematic, still problematic, though. 10" microgrooves and 78s are much worse. And 45s are the worst. Also things do not sound all that good with anti skating at 3 grams.

The machine sounds and performs best with the anti skating scale set at 1 to 1.5 grams for the 3 gram tracking force, depending upon whether a conical or elliptical stylus is used. Auto start and stop work. Channels seem more balanced and there is less distortion. So I guess .... things are sort of OK.

But it would be nice to have (both) the anti skating dial scale (and the tracking weight scale) calibrated correctly .... (Tracking weight scale calibration is a topic for another thread.)

The Service Manual says not to mess with the anti skating mechanism under the tone arm. Special tools are required, Dual's test record and Dual's anti skating force meter. Has anyone ever messed with this stuff and come out alive?

I do not have one of the blank anti skating test records (wouldn't mind having one, though). I have read (but do not know for myself) that they are OK if they come with good instructions and the instructions are followed. My possibly ill-informed understanding is that the anti skating force is to be set to the point where the tone arm drifts ever so slowly towards the middle of the record and not so that it remains static in place. But what do I actually know of this? Nothing really.

Thoughts, comments, suggestions, advice?

Is there another explanation for the malfunctioning of auto start/stop other than excessive anti skating force?

 

[D_Canard]

OK. After browsing about this archive of information here (a rabbithole of ness), I finally noticed this thread among the suggestions down below:

All Anti-skating mechanisms are wrong!

I read through a 1967 paper by Shure’s Chief Engineer James Kogen on the topic of tonearm skating. I was able to discover some interesting findings that the turntable/tonearm manufacturers didn’t get quite right in designing effective anti-skating mechanisms. • Skating is the result of the...

audiokarma.org

And within this thread, this post:

All Anti-skating mechanisms are wrong!

I use a Ortofon Concorde Nightclub Mk2 @ 3.1 grams which have a 0.5 x 1.0 special elliptical I use about 1.75 of antiskate on a Technics SL-1200 Mk7 Far less than a 0.3 x 0.7

audiokarma.org

And within this post, this link to Sound-Smith:

https://www.sound-smith.com/faq/how-do-i-adjust-anti-skating-my-cartridge

The Sound_Smith tip about setting the arm down in the mostly uncut area of the run out groove to see how the arm behaves as a test for anti skating force matches with what I have read about the use of blank anti-skating test disks--the arm should move very slowly inward (until the run out groove picks up the needle in the run out groove test).

The run out groove test is more easily done with a manual turntable than an automatic, but the test with the 1229Q suggests that I have an appropriate anti-skating force set despite what the dial says. And auto start and stop both work just fine at all speeds with my settings.

So my concern is not with anti-skating, per se, but with the calibration of the dial. The anti skating mechanism provides an insane amount of force if it is set to match the tracking weight. But does it really matter if the numbers on the dial are wrong but the anti skating is OK? Probably not unless I am a perfectionist. But then again it might if I were ever to use a very light tracking cartridge. I might not be able to set the dial low enough.

I should try the zero tracking force with zero anti-skating force float test to see if the arm is forced outward.

 

[loudnoises]

I find that about 3/4 tracking force is where my anti skate sounds best on my 1219. The number is really insignificant. It usual rides just under 1g, with about 1.25g tracking force.

It's not a linear mechanism I don't believe.

You are neutral balancing and then setting tf via the dial yes? Balancing to a tf with the counterweight on this arm isn't advised.

 

[D_Canard]

I find that about 3/4 tracking force is where my anti skate sounds best on my 1219. The number is really insignificant. It usual rides just under 1g, with about 1.25g tracking force.

It's not a linear mechanism I don't believe.

You are neutral balancing and then setting tf via the dial yes? Balancing to a tf with the counterweight on this arm isn't advised.

Thank you for the kind reply.

I don't think it is a linear mechanism, either.

I am neutral balancing according the user manual instructions, and then setting tracking force with the dial. I then check the tracking force with two different balance scales and find that the actual tracking force is wrong, both scales agree. I do fine adjustment with the counterweight to get the tracking force correct. The user manual has instructions for using the counterweight to adjust tracking force.

I need to do some more testing today and have a look to see if the sealed adjusting hex nut has been tampered with.

 

[Thorsten R.]

I have a 1229 and a 1228 beside others. I adjust the skating compensation with a test record (e.g. Ortofon) at all turntables. What I find astonishing: The diverse skales and recommendations never fit. They are dependent mostly on the actual stylus. A Black Diamond or a ATVM95ML need a lot of compensation, an Ortofon F15E a normal amount, a NOS N95ED very little, a NOS ATN13 almost none. To name a few examples. May be it is dependent on the quality of the polishing. So: Get yourself a good test record and adjust using it. This may be an approximation to the value needed but it is a realistic one.

 

[Doug G.]

I find that about 3/4 tracking force is where my anti skate sounds best on my 1219. The number is really insignificant. It usual rides just under 1g, with about 1.25g tracking force.

It's not a linear mechanism I don't believe.

You are neutral balancing and then setting tf via the dial yes? Balancing to a tf with the counterweight on this arm isn't advised.

It's the same with my BICs, AS about 3/4 VTF. Of course, the AS number doesn't actually represent force in grams. It's just convenient numbers to set it.

Also, I arrived at my settings while setting up for CD-4 play which is more critical than for regular two channel play.

Doug

 

[D_Canard]

@Doug G.

@Thorsten R.

Thank you for the replies, but things are a little more complicated that just setting the anti-skating. I am concerned about the hardware as we shall see immediately below.

 

[stereofisher]

I find that about 3/4 tracking force is where my anti skate sounds best on my 1219. The number is really insignificant. It usual rides just under 1g, with about 1.25g tracking force.

It's not a linear mechanism I don't believe.

You are neutral balancing and then setting tf via the dial yes? Balancing to a tf with the counterweight on this arm isn't advised.

Several of my Duals work better at 3/4 antiskate. Just this week a 1015 i have the arm was not landing on the record. Reset at 3/4 and all is well. Did not affect the sound quality.

 

[D_Canard]

OK, so with the turntable set absolutely level, the tone arm zero balanced, and the anti-skating set to zero, there is still a small amount of anti-skating force applied to the arm. It drifts outward until it is stopped by one of the shut off linkages under the deck.

Turning the deck over and having a look at the anti-skating mechanism, I see that the red sealing paint on the hex nut for the cam and the arm set screw is broken, and things look a bit strange. It has been messed with.

Here is a comparison between the service manual illustration for anti-skating set to zero and my unit set the same. The orientation hole in the cam seems a little out of alignment, over to the right a bit. And the two mechanisms do not look entirely the same.



Now here is where it gets really strange, a comparison between the service manual illustration showing the mechanism set to 1.5 grams conical and my unit set the same. If the manual illustration is not wrong, there is something very seriously messed up with my mechanism.


However, the manual illustration sort of matches my unit set to 1.5 grams CD4,



I am trying to juggle and manipulate a mental image of this all in my head and am wondering if the cam has not been installed/re-installed upside down?

 

[loudnoises]

OK, so with the turntable set absolutely level, the tone arm zero balanced, and the anti-skating set to zero, there is still a small amount of anti-skating force applied to the arm. It drifts outward until it is stopped by one of the shut off linkages under the deck.

Turning the deck over and having a look at the anti-skating mechanism, I see that the red sealing paint on the hex nut for the cam and the arm set screw is broken, and things look a bit strange. It has been messed with.

Here is a comparison between the service manual illustration for anti-skating set to zero and my unit set the same. The orientation hole in the cam seems a little out of alignment, over to the right a bit. And the two mechanisms do not look entirely the same.

View attachment 3258383

Now here is where it gets really strange, a comparison between the service manual illustration showing the mechanism set to 1.5 grams conical and my unit set the same. If the manual illustration is not wrong, there is something very seriously messed up with my mechanism.

View attachment 3258386
However, the manual illustration sort of matches my unit set to 1.5 grams CD4,

View attachment 3258388

I am trying to juggle and manipulate a mental image of this all in my head and am wondering if the cam has not been installed/re-installed upside down?

I think it's oriented correctly, if you draw a line from the hole to the mounting hole, the lower left seems to be a larger lobe, both in yours and the illustration. Angles are touchy in pictures.

But it does seem that it is not aligned correctly with the topside indicator.

There are definite experts on this table that frequent this forum. One will likely chime in.

 

[D_Canard]

Also, I note that there is a difference in the two springs attached to anti-skating mechanism. One looks new, shiny, and taut. The other looks old, floppy, grubby, and bagged.

It is hard to get a picture. I will try later.

The two springs seem to have different part numbers. It is not clear which is which in any of the diagrams. I guess that they are exploded diagram number 241, pn 216 796, and diagram number 265, pn 201 183.

I am wondering if some of the problems here here might be symptomatic of one of a pair of springs having lost its tension?

Should they both be replaced? Matched new and new?

 

[D_Canard]

OK. I am getting somewhere now.

I posted on Dual-Board.de, and a very kind soul there pointed out the anti-skating cam in my 1229Q is entirely the wrong part. It is a cam from a 1209, a machine with a very different tonearm geometry. Hey, what could go wrong? It's a cam.

So now I need to look for the right cam.

Also I re-examined the springs in better light and they look OK. So I will start with the cam.

 

[loudnoises]

Did they tell you if it only fit the 1229q or does it share with other models? Plenty of parts units in our collective hoards. But the 1229q is a fairly desired unit, might be a 3d printed option as well.

Glad you're sorting this out.

 

[D_Canard]

Did they tell you if it only fit the 1229q or does it share with other models? Plenty of parts units in our collective hoards. But the 1229q is a fairly desired unit, might be a 3d printed option as well.

Glad you're sorting this out.

No. They only told me to get the part for the 1229, so I assume that the 1229 part is the same as that for the 1229Q. My understanding is that the 1229Q is basically a 1229 with some modifications, lighter weight head shell, different impedance RCA cables for CD4, and a bit more plastic than on the 1229. However, I do not know this for certain.

Here is the part I need:

 

[Mearle]

Assuming no mechanical issues, the only way to do it is with a test record and scoping the output, the rest is just a waste of time imo.
I used to use a test record of a 1Khz with a modulated 10Khz wave form on the 1 Khz. Scope the output from a test receiver and the output will not lie to you. Otherwise you will never find the optimal point, its like balancing a hair on the edge of a razor blade. I typically found that just the right amount of VTF was approx 1.5g. but that is just another variable to contend with for the optimal performance.

 

[D_Canard]

OK, a bit of research suggests that this same part was used in a wide variety of later Dual turntables.

From a vendor of 3D printed replacements:

Dual 1229 turntable replacement anti skate cam 225-176. Our exclusive and proprietary design matches the shape and dimension of the original cam and has been precisely fabricated for a proper fit. Our cam can also be used in the Dual 601, 701, 1241, 1245 and other models.

 

[D_Canard]

Assuming no mechanical issues, the only way to do it is with a test record and scoping the output, the rest is just a waste of time imo.
I used to use a test record of a 1Khz with a modulated 10Khz wave form on the 1 Khz. Scope the output from a test receiver and the output will not lie to you. Otherwise you will never find the optimal point, its like balancing a hair on the edge of a razor blade. I typically found that just the right amount of VTF was approx 1.5g. but that is just another variable to contend with for the optimal performance.

Thank you. I will get to actually calibrating the play anti-skating once the hardware issues are dealt with and I have a good zero force baseline to start from.

 

[D_Canard]

One more question here. Does anyone have experience with how the 3D printed cams compare in specifications, durability and performance to the originals?

My intuition suggests to me that the original, moulded from molten plastic, is likely to be more structurally cohesive than the 3D printed replacement, essentially welded together layer by layer. But I am not a structural engineer, and intuition is sometimes wrong.

So Pros and Cons

Original Cons: The original will probably be difficult to obtain and will probably be expensive if found as NOS. A used replacement, being some half century old, will have suffered some mechanical stress in its life, and I have read, perhaps somewhere in this forum, that these cams are eventually subject to fatigue cracking.

Original Pros: NOS can also be read as Nice Old Stock . An original part is undoubtedly the right part. The original may have greater structural integrity.

3D Printed Cons: The printed part may be lacking the structural integrity of the original. There is only the manufacturer's word that it is indeed the right part, identical in all ways, except in materials and manufacture.

3D Printed Pros: I could probably have a 3D printed one in my hands within a day or two, certainly within a week or so. They are modestly pricey for a small piece of plastic, but the emphasis here in the "modestly pricey" is on the modest and not on the price. I am likely to be long dead before I get to find out if a 3D printed cam disintegrates from structural fatigue .

 

[loudnoises]

You may be overthinking this a bit. It's very easy to make basic precision 3d printed parts to the same specification as a molded part. This one isn't complex.

I would buy a new printed part and be done with it.

 

[D_Canard]

You may be overthinking this a bit. It's very easy to make basic precision 3d printed parts to the same specification as a molded part. This one isn't complex.

I would buy a new printed part and be done with it.

A bit? Just a bit? LOL

Overthinking is what I do best. Never entirely a fan of Occam's Razor.