Anti-skating vs. "lateral balance" on Sansui SR-2050

mcleavy

New Member
I recently purchased a Sansui SR-2050E turntable for a friend, but became fascinated by its funky vintage (early ‘70s) character and quality construction and have been playing with it myself. It’s a slick little turntable with arm lift-off initiated by an electronic sensor and the silkiest cueing mechanism I’ve ever experienced. The thing that has me puzzled is the anti-skating adjustment.

There is a rod protruding from a block mounted on top of the gimbal (see first picture) that suspends a small counterweight on a thin wire. The owner's manual refers to this as the "Inside Force Canceler (Anti-Skating).” To quote the manual: "Position the loop of the bias weight in the groove corresponding to the stylus pressure being used." The center groove, marked in red, corresponds to 2 grams which I am using with the Shure M75E cartridge. So far, so good.

Now it gets confusing for me. The sliding cylindrical weight on the right side of the gimbal is referred to as the “Lateral Weight.” Instructions for the lateral weight read, “To adjust the lateral balance of the arm, move the lateral weight in the direction of the arrows until the arm stops swinging over one way or the other, while raising the rear bottom edge (hinged side) of the SR-1050C about four inches.” (The 1050C is the same tone arm as the 2050C/E but without auto lift-off.)

I followed the instructions with the exception of lifting the rear only 3”+ rather than four which seemed too precarious. I was able to balance the arm in the lateral plane doing this. However, when I returned the turntable to a level position, the tone arm would swing back to the rest regardless of the setting of the lateral weight. The second and third photos are of the turntable propped up and the arm stationary above the platter.

One thing that could factor into the equation is the fact that the M97E is mounted as far forward as possible in the head shell but still doesn’t quite meet the overhang specified by Sansui.

I’ve always thought that if an arm was balanced in the lateral plane that it would remain motionless at any point above the platter. So, what’s the difference between an anti-skating adjustment and lateral balance? Why can’t I balance the tone arm in the lateral plane with the turntable sitting level and what is the purpose/interaction of the two weights? Can someone who was paying better attention in physics class help me out here? Thanks…


SansuiGimbal.jpg


SansuiFloat1.jpg


SansuiFloat2.jpg
 
The reason it moves to the rest is that the anti-skate is working properly. Once you put it in the groove it should be fine.
 
If you were going to adjust the lateral balance it would make more sense to do it before you applied any anti-skating force. I don't even understand the location on the Sansui. Every other arm I've seen with lateral balance has it on the left side. In any case, it's not critical.

But I'm curious as to Sansui's directions for overhang. The Shure should not be in the most forward position. What exactly does Sansui say to do?
 
Overhang

"But I'm curious as to Sansui's directions for overhang. The Shure should not be in the most forward position. What exactly does Sansui say to do?"

The Sansui instructions are not too concise. In the capture below, I interpreted "Spindle" in the diagram to mean the centerline of the spindle. When I positioned the head shell adjacent to the spindle and measured, the stylus came up about 3/32" short of making the 19/32" indicated in the instructions. The cartridge was installed when I got it, so apparently someone else had a similar interpretation.

Just in: Now that I captured the instructions on overhang, I see for the first time that the hole between the two mounting slots in the diagram is dotted, indicating that the spindle is directly below the cartridge. I had previously thought this to be a hole in the head shell. Regardless, I don't think positioning the head directly over the spindle would give a significantly different measurement than I got.

I know there are more sophisticated ways to set overhang, but I've never had occasion to research them. Maybe this is a good time to look into it...

"I don't even understand the location on the Sansui. Every other arm I've seen with lateral balance has it on the left side."

Since we have two weights in action, maybe the hanging weight is the "heavy weight" and the sliding lateral weight offsets (fine tunes) it to the proper degree, giving an inside bias equivalent to what you might get with a single sliding lateral weight on the opposite side of conventional tonearms?

Sansui must have had some theory in mind when they designed the turntable. I have read that it was considered a relatively high end tonearm in its time and was sold separately for installation on better quality turntables.

Or maybe the turntable is just "funkier" than I realized. Still, good clean and cheap fun; and, we can't ignore the fact that it looks cool!

Thanks for the replies. Good forum!


SansuiOverhang.jpg
 
There's something wrong with your cartridge. That stylus is protruding way too far forward--as if it doesn't fit properly. Are you sure it's all the way in? Is this the cartridge that came with the turntable? Exactly what is written on the stylus and what is written on the cartridge body?
 
I am in the process of setting up a Fidelity Research tonearm that has the adjustments that you are curious about. The order of adjustment is:
1) Position stylus at correct overhang, 15mm in your case past the center of the spindle
2) Zero the tracking force by balancing the tonearm at record level
3) Set lateral tracking weight as described for your turntable

"The lateral balance device is provided to correct for the sideways tendency in tonearm movement that occurs when a turntable cabinet is not used on a horizontal stand. Practically speaking, no problems will occur if the turntable is installed level. Therefore, you ordinarily don't need to pay too much attention to this adjustment."

4) Set the tracking force
5) Set the anti-skate
6) Set the arm height

As you can see the lateral balance is done with no other forces acting on the tone arm, and it not real critical.

You should be able to get the overhang set correctly. As shown in the capture, the stylus is just about at the end of the headshell. I just checked the cartridge mounted on a Denon headshell and it is also very close to the front edge of the headshell for the proper overhang, 15 mm in the case of this turntable, too.

I agree with Howard, that cartridge stylus assembly looks a bit off. Maybe some investigation is warranted.
 
I’ve always thought that if an arm was balanced in the lateral plane that it would remain motionless at any point above the platter. So, what’s the difference between an anti-skating adjustment and lateral balance?

I've never had a tonearm with adjustable lateral balance and haven't had one with anti-skating for over 20 years, so I'm not even going to try to discuss the physics or why you need either, but anti-skating is only supposed to compensate for forces generated by the interaction of the stylus with the record groove. So if your arm is in lateral balance and you add anti-skating, it's going to tend to swing outward when the stylus is not in contact with a record.
 
Cartridge installed in SR-2050E

I took a look at the cartridge in the 2050E and I’m a little embarrassed. It’s a Shure M93E with a Shure 5X stylus rather than a Shure M97E that I mentioned in the original post. The turntable is at another location and I was writing from memory, which failed me once more. The 5X stylus did catch me off guard though. I understand it to be a less expensive replacement stylus than the N93E.

“That stylus is protruding way too far forward--as if it doesn't fit properly. Are you sure it's all the way in? Is this the cartridge that came with the turntable??” (Howard)

My limited experience with cartridges goes back to some V15’s in the ‘70s, but the 5X seemed to seat properly in the M93E. Possibly you can tell something from the photo?

The Sansui SR-2050C came with a “Sansui” cartridge, but this SR-2050E (Economy, Empty?) was sold without a cartridge. Since the M93E was available in the mid-seventies, I suppose it’s possible that the original owner purchased the cartridge at the same time as the turntable.
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Now to really show my ignorance. Several replies state that the tone arm should swing toward the edge of the platter when anti-skating force is applied. I believe this because you guys are experts and I am not. My understanding, though, is that anti-skating is supposed to compensate for external forces on the stylus; i.e., the force exerted by the outside of the groove as it steadily nudges the stylus towards the center of the record. It seems this lateral force exerted on the stylus by the outside of the groove would create a bias toward the information encoded on that side of the groove. Since we want the stylus to read each side of the groove equally, shouldn’t the anti-skating force be directed towards the center of the record so that the stylus tends to remain centered in the groove and reading both sides of the groove "equally." Why do I have this backwards?
______________________________________________

I think this neat old turntable deserves a better cartridge. Without starting a thread within a thread, Shure M97xE, Grado ___, or what for less than $120? I don't think my ears can hear more than $120 worth anymore.

Thanks for the suggestions, Blue Shadow, I will experiment some more as time allows. The sequence makes sense.


SansuiCartridge.jpg
 
The anti-skating function is there to compensate for the skating force.This skating force is created by the angle from the parallell force in the groove and the pivot point.This skating force is allways pointed towards the center of the record,and this should be compensated for.
The lateral weight IMO creates more problems then it is supposed to solve.
This is because the mass in this weight will add to the tonearm mass,and the compliance in the rod is normally to high.If the table is well in balance it´s much better not to use this.
/gusten
 
My mistake--the stylus is fine. I just can't understand why it's so far forward in the headshell.
 
Sansui lateral balance

I've had several of these tables (going back to a 1050C I bought in Denver app "78), never could tell if the lateral balance made much difference. I would be tempted to set it at the mark (for 2 grams stylus pressure) and leave it there.

My eyeball & pea brain tells me that what it does is apply an equal load on the bearings. It appears that the anti-skate weight not only works to equalize left/right pressure on the stylus, it also tends to apply downward pressure on the inside bearing and upward pressure on the outside bearing. It pulls from the top, think about it. The only thing the lateral weight could do is adjust the downward pressure on the bearings as to equalize things. Again, eyeball & pea brain line of reasoning. No doubt, I could be wrong...wouldn't be the 1st time.

I would set the anti-skate with a test record. Actually, the marks on the counterweight & anti-skate weight seem to be spot on, at least when using 1.5 or 2 grams downward pressure, when checked with a Shure stylus guage and a test record.

As far as a different cartridge. Years ago I used an M91ED set at 1 gram without any problems. The arm always worked great with the original Sansui cartridge set at 2 grams. When running a Grado Red at 1.5 grams, I would get a definite Grado dance, I didn't see how the cartridge could continue to track, but it did.

Personally, I would look at a AT 440ML or MLa, or a Ortofon Super 10-20. I guess the Shure 97 is a good cartridge also. At one time I owned an Ortofon Super 10, an OM40, VMS 30, Shure Supertrack III, AT 440ML, and Grados Green, Red, & Gold. Pretty much compared them at the same time, now I'm running the OM40 & and the 440ML. The OM40, Super 10, and the 440ML just sound more alive, with the 40 coming out on top, overall more information than the 440ML. The Super 10 is pretty good for a cheap cartridge. VMS 30 sounds dull by comparison. The Supertrack III sounds duller still, with the Grado's really sounding dull. And they want to do the "dance".

Just remember, everything I've just said are my personal observations. Just my humble opinions.

For what it's worth,
Chas
 
As a new owner (yesterday) of a Sansui SR-2050C the information in this string is terrific. I am wondering if there is a copy of the user manual for this turntable available anywhere? My turntable came with a Stanton 681EEE Cartridge - but I see in very fine print on the turntable the notation "Repalcement Stylus Model SN-31". Also a couple of observations - It seems the lateral weight on my turntable is at say 2 o'clock relative to the arm (it angles slightly up) - in the photos here it seems like its closer to 3 O'Clock (parallel to the ground) - is mine bent? Also on my table the small hole at the back (to the right of the arm) has a little rubber stopper - I suspect this is for adjusting or lubricating.
 
Visman

The rubber stopper covers an adjustment, maybe when the arm lifts at the end of a record, can't remember.

If you want a copy of the owner's manual, send me a PM. I'll run one off on the copy machine & mail it to you, free gratis. I've done it for other people. If you're so inclined, you can make a donation to AK.

Chas
 
A thank you to Charles for sending me a user manual at no charge - I was so moved I sent $25 to AK!

Table works great - set up was real easy. One interesting observation - the spindle on my motor had built up years of gunk and it caused the table to run a little fast! A good cleaning and it's now spot on.
 
I have one of these beasties also, and have been puzzled with the 'fishing line' anti-skate. It seems to be rather hit and miss to get it to behave properly.

BTW, if anyone has a spare dustcover 'kickstand', mine was lost in my move up north.
 
1050C anti skate weight?

Great thread! I've got a 1050C but it is missing the anti skate weight. Could someone who has one (the weight, I mean) tell me how much it weighs? If I knew that I'm sure I could find or make a weight for it.

Thanks,

Martin.
 
wow, what kind of equipment would one use to weigh such a tiny thing? I don't have a drug scale... :D

A split shot sinker and some 2 pound test would be about right der hey.
 
Hmm, I didn't think of that. I don't have anything around here that would weigh anything that small either.
 
I tried weighing my bias weight on a letter scale and nada so it is less than an ounce - which I suppose I should have known. The manual does not reference the weight, however each of the tiny graduations on the bias lever (what the weight hangs on) represent .5 grams of stylus pressure - so I would guess the bias weight needs to be pretty accurate. On another note I am surprised these little Sansui's don't get a lot of love - solid wood - cool/funky anti skate - great sound - whats not to love?
 
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