Great question, one I've never had an answer for.

I always figured...

Once you have a cartridge mounted, you have established a fixed relationship between the arm/needle and the platter/LP. Since the shortest, most efficient line from the bearing to the needle would be a straight line, I could only relate to straight arms.

The curved or "S" shaped arm always seemed like they did nothing except to add mass. Once, I figured maybe putting that curve in an arm would add off axis mass and help with anti-skating forces by adding mass to the side of the needle that was on the part of the groove facing inward? Then I realized I had it backwards, so maybe that extra mass on the outside caused some torque/rotation in the arm and "rotated" the needle in such a way that it was able to more forcefully push on the outer facing groove and resist the skating force of the inner facing groove.

Then I thought it was entirely based on having detachable headshells that a curved arm would allow to screw on "straight" onto the arm so the cartridge offset would be based on arm geometry while at the same time allowing headshell mounting to be "straight ahead."

Then I gave up thinking about it and stuck with straight arms.

I'll be interested in seeing the arm shape explanations that come in here!

Related question: Has there ever been a curved or "s" shaped unipivot arm?

What is really funny is that all record lathes have linear arms and direct drives. So do the worlds best turntables.

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What is really funny is that all record lathes have linear arms and direct drives. So do the worlds best turntables.

Lathes and turntables are two totally different beasts

The real key to me of any TT system is the drive system...how quiet and how isolated from air and earth-born vibrations is the platter/chassis?

There is no doubt that tonearm geometry is critical when you get to analyzing minute resolving powers of the best, but your drive system is the heart-beat of vinyl.

I have not found a good substitute for great bearings and a massive platter. Basic physics is at work here. When I was younger one of the best TT packages I owned was a Technics SP10 direct drive with one of 2 "S" shaped SME arms. The blackness of the backgrounds was remarkable to me. I regret ever selling them.

I have also had a newer Throens 850 which I think is tremendously quiet, very black backgrounds, in a simple, but well excecuted bearing, heavy platter, good motor with belt drive system. With the standard Rega "straight" arm it is, to me, a great buy. I am sure the VPI and Regas in this price range are the same.

I curremtly have a Rega P3 which I really enjoy for not only it's sonic qualities, but it's utter simplicity. I have also had in my home Music Hall, 5,7, and 9's which are also excellent performers at there respective price points. No one has gone wrong buying a Music Hall product. I still have a vintage Project DR1/220 in my "70's" system in my home office that still works and sounds great...for what it is. It has a Technics style "s" shaped tonearm with belt drive. All original. I would not trade an sub $500 table for it. A Rega P5...maybe!

Unless your system has great recolving power and you are using at least a $1K phono stage from Mr. Fremmer's recommendations, the "s" shape of tone arm may not be the biggest problem.

My order of importance is:
1.) Cartridge/Phono stage
2.) Platter/bearing system
3.) Tonearm

After 30+ years spinning vinyl I do believe MF is right about owning some type of record vacuum cleaning system. Cleanliness is next to Godliness in trying to extract all the gooves have to offer. Santa will bring me a record vacuum cleaning system this year or there is going to be trouble. LOL

Good luck.

I have a different question. I have a Thorens TD 160 which has been my main turntable since 1976 with V15-Vmrx cartricge. But I hardly use it since my floor isn't sturdy enough and so walking is a very risky thing when a record is playing. I have considered upgrading for some time, which would be accompanied by my building a shelf for the table that is tied into the wall.

Question, how much would i need to psend to make a real upgrade of my current setup, and/or is there another path I need to consider? Say an isolation platter?. Any shelf construction tips would be appreciated as I'm an electrician, not a carpenter.

Lets address the floor issue first. Is this the first floor of your home and do you have a basement or a crawl space? www.musicdirect.com has many isolation platforms, but the heavy foot-falls will require more than that. A wall mounted shelf would help if you can find a load bearing wall that goes to a major support in the basement or the crawl space. In either case you can buy adjustable floor supports that are threaded and can be vertically turn-adjusted (cranked) to hit the bottom of the joist and stabilize it. If it is a dirt crawl space you should put a 12" or 16" square cement patio block below it in the dirt. One or two supports may be enough the solidify the foot-fall vibrations as you walk. The wall mounted shelf will help as well.

The turntable issue is more one of should you upgrade your phono stage first. The table you have is decent for sure. If you like the sound of it make sure you are buying 1 or 2 replacement stylii for it as they may become in short supply as Shure has stopped making the Type V MR.

Let me know if you have other issues. This should be fixable with a few things from Home Depot or Lowes.

I have thought about going into the dirt crawl space and reinforcing the floor from below. And the electronics sit against a load bearing wall, so finding good support isn't a problem. I suppose I could run a few 2x6's across the floor joists, and then put heavy supports underneath first and see how it stabilizes things.

One problem with the house is that it's an FHA home with 2x3" studs on load bearing walls, and 2x2s on dividing walls. I had never imagined such a thing until I tore the bathroom apart for a major remodel. So it isn't quite so stout as I'd like.

As far as my phono stage goes I don't think it's a problem. I upgraded to a McIntosh 6500 integrated amp a couple years ago, but by then I was sick of the skips.

After i do the bracing perhaps an isolation platter would do what is needed. The table was always jumpy, I know because I used it in college and always had the best luck when it was mounted on a shelf.

Once you've done a little "dirty work" under the house I think you will be in good shape. When your are down there you might also want to do a couple of things: Clean out all wood debris that you can; put down a poly vapor barrier under the entire crawl space that you can reach and leave about a 1-2 foot rim of exposed dirt at the outer inside-edge by the cement block foundation; check your cross vents and make sure they have good screen and wire mesh on them to keep rodents out!!!. All they need is a 1" hole to get through. Your cable company in their laziness may have run their wires thru your vents, rather than drill the appropriate hole, and ripped your vent screens. Try and relocate the wires if you can.

Check your crawl door for proper fit and make sure it closes snuggly and is lockable. I found a homeless man living under a single-woman's house once...no kidding. Keep it locked.

If you need new vents they are about $15 each at Home Depot, are a push-in fit the same size as a standard cement block, and have a bi-metallic thermostat that closes the louvers when it gets cold keeping your floor warmer in the winter and with the vapor barrier will keep the ground moisture from entering your sub-floor.

This little project is not a bad as it sounds and you will only need to do it once. The vapor barrier plastic (6-8 mil) comes in rolls and once you position it you just start rolling and at the end turn around move over and roll your way back. Over lap the runs by about 3-4 inches.

Then I would put the patio block down on top of the vapor barrier and do your supports as you see fit. With a friend it should not take you very much time. I hope I am not spoiling your day. You'll just wish the previous owner had done it for you. I am hoping you live in the southern U.S. and not tyrying to do this in Buffalo or Chicago right now. If so, this just became a spring project.

Hi, I am another newcomer to the forum. Maybe the wise old hands can give me some advice. I have a Sota Sapphire TT with a Syrinx PU3 tonearm. Unfortunately the wiring harness got damaged and I now have to replace it.(The solder connections at the bottom of the arm to the interlink to the phono stage came adrift). I plan to use the CARDAS tone arm wire as it is quite affordable. I disassembled the arm and discovered that the yellow earth wire was not connected on the tonearm side and only to the eart stud on the turntable. The wire was pulled into the arm tube but stopped halfway to the cartridge end. Does anybody know where and how I should earth the tone arm? I experienced quite a lot of hum even before the wire harness got damaged. I only have a very brief (3 page) manual for the arm and would appreciate any help in setting up the arm.

Hey Jim - I've got a question for you. I've got a couple hundred LP's sitting here that I "gave up on" ten years ago because everytime I went to play them, my phono needle either got clogged with lint/dust or some sort of grungy substance. I even went out and purchased a new cartridge and needle and still happened. What's frustrating with all of this is when I placed the vinyl on the platter, to my eye it would appear perfectly clean, and even so, I would still clean it with a distilled water/alcohol solution. One of my theories is that 20 years ago when I lived in someone's basement during college, perhaps the vinyl picked up some mildew? (Note: there is no apparent damage/mildew on the LP jackets.) Do you have any suggestions? You mentioned a record vacuum cleaning system. Perhaps would work for me as well? I appreciate whatever advice you have to offer. Thanks

The weather has been good right now, but it still seems like a spring project to me. I am well aware of my crawl space. I replaced 100% of the house wring a few years ago, and had to do considerable structural work on this house. In fact I've spent entirely too much time in there. But as you say, I should only have to do it once, and doing it will have benefits beyond the sonic variety.

Now all I need is to get the boommobiles to go away.

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The reason you would choose to buy a turntable with a straight arm as opposed to a curved arm is for scratch control. A straight tone arm has a completely different position, angle and range of grip and is set-up so DJs can scratch with high precision without the worry of skipping records.

I think you are confusing the issue. The OP was talking about the difference between s-shaped and straight arms, both with a bent (offset) headshell. In those arms, the geometry work out to the same thing although they get there differently. You, I believe, are talking about straight, non-offset arms used for scratching. With those, one gives up correct tracing geometry to get more reliable scratching without the arm skipping.

Kal

CJO, I was just browsing through and came upon your post. Since it has been a couple of months, I don't know if you have solved your dust bunny problem, but here's what I do to LP's that habitually offend. First, I have a VPI record-washer, their cheapest model (about $450-$500), which has been superb. I have used a couple of different fluids in it, but the Record Research Lab fluid (I order mine from Acoustic Sounds) works best. I have over 2500 LP's, many of which are at least 20 years old. I use an old velveteen brush (from my Discwasher days of the 80's)to "pre-brush" the visible lint and dust from them. This leaves a bunch of crud on the brush, which I sweep off with a dry sponge. Then I wet-clean them with the VPI. Going from there to the turntable, they attract some dust from the air because of the static the VPI cleaning generates. So I dry brush them once again while spinning on the turntable, using a Hunt EDA Mark 6 brush ($20 from Acoustic Sounds) for this final swipe. Then they play fine, with no noise, no grunge. For LP's I have recently cleaned, I don't need to wet clean them again for awhile...I just put 'em on the turntable and dry-brush them with the Hunt. Hope this helps. Clifton