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Converting Technics "S" tonearm to straight?...

cube-tube

cube-tube

Super Member
Has anyone one here done something like this? And I don't mean swapping out the stock arm for am SME 309 or anything like that. I mean actually removing the "S" part of the arm and making/installing a straight tube. Sort of like Funk Firm's FX-1200 arm or the Jesse Dean Design Carbon Fiber tonearm?

Funk Firm FX-1200
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Jesse Dean Design
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I'm not too sure about the Jesse one (looks too short and I think mainly meant for scratching), but I do like the idea of a straight arm, and the fact that I could not only keep the easily adjustable VTA, but also the auto function of the arm.

Where I work, I have access to aluminum, stainless steel and brass tubes of various sizes and gauges. It looks like it would be somewhat easy to do, but I'm also surprised that no one on here or other sites have done this. At least, I haven't seen anything yet.

Any thoughts and/or suggestions? I already have an idea about dampening for the tube on the inside and outside too. :D

Please let me know what you guys think!
 
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a purely straight arm with no compensation for the correct overhang like the Jesse Dean Design is a horrible idea for any sort of serious record playing. It will eat records alive. Proper straight arms have angled heads to compensate for this, curved arms curve before the head.

Why do you want to do this anyway? What would you gain?
 
Notice it has the offset headshell though. The Jesse Dean one looks like someone yanked the straight P mount arm off a linear tracker and grafted it to the SL1200 pivot. No good for playback for all the reasons mentioned.

I expect much of the gains from a straight arm is a simple matter of less mass. Shortest route between any two points is a straight line, which translates to less physical material in the tonearm, therefore less mass. Also, its somewhat easier to make a straight tube than a curved one, at least if your tube material is something other than metal which bends.
 
Greyson said:
Well the FunkFirm arm is 1000$ so it must have some pretty huge benefits.
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This is the proper way to do a straight arm:

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Please note the offset cartridge mounting.

This is the extraordinarily improper way to do a straight arm, and while they are commercially made, they are intended for more groove-staying power when scratching and backcuing when DJing:

jddassault2.jpg


Please note the lack of offset that is necessary to approximate the original cutting head's angle when tracing over the record.

I ask what's the point because I think a good arm is a good arm, and I have heard bad straight arms, great curved arms, and vice versa. Heck, vinyl dubs I made with the lowly stock Lenco arm (which gets no love) caused a former vinyl mastering engineer who cut on a Neumann lathe to remark "I've never heard vinyl sound closer to the master tape".

If it sounds good, I say leave it.
 
I converted a Pioneer arm with a piece of carbon fiber tube a got from the local hobby store. Effective length was around 12".

It worked very well but I think it would be better with a tapered tube or two pieces of different od tube such as the black widow uses. This is supposed to help reduce sonic vibrations through the arm.

Some people didn't think it would work that well because the horizontal bearing isn't perpendicular to the offset angle as it is with many arms. This may help tracking although most of the arms that have interchangeable s and straight arms are this way from what I have seen. I'm sure I could re-drill the arm but I didn't find it necessary to do so.

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Very nice, Denny!

Nice table you got there, too!

Where'd you get the headshell for this custom arm?
 
Well I'm not a complete schmuck guys. Give me a little credit.

I know quite well about needing the cartridge offset as well as having the ability to adjust overhang. I pretty much figured that was a given, hence why I didn't bother mentioning the offset/overhang.

For the headshell, I was thinking something in the lines of a DIY version of the RS Labs designs. Mainly the one based off of the SME headshell.

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I think I could fairly easily fab one of these up using a generic version of this headshell, cutting it up and making small brackets and pivoting mounting plate. It shouldn't be too hard, and would still be a "quick release" style.

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thedelihaus said:
Very nice, Denny!

Nice table you got there, too!

Where'd you get the headshell for this custom arm?
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I think once I finish fixing the rust on my moms car and powder coating her wheels I will have time to work on this one again.

The headshell came from a Pioneer PL-6/7/8 straight arm table. It worked great for this conversion since it had almost the exact size hole I needed. I just had to turn down the end of the tube slightly to get it to fit. The offset wasn't at the exact angle I needed but it had enough wiggle room in the mounting holes to adjust it where it needed to be.

The arm worked well but I wasn't that excited about the cosmetics of how the arm mounts to the armboard. I may machine something different in the future but I bought a Black Widow to mount on the table instead.

I found a couple different high compliance carts such as a Grace F-9E and ADC XLM. It should be fun comparing the lot along with the Stanton I had mounted on the custom arm.

cube-tube, I would try looking for some other way to deal with the offset angle instead of the contraption on that SME arm. I'm sure it works but looks like it would add a lot of extra weight at the end of the arm. This kind of defeats the purpose of a straight arm which is low mass. It doesn't exactly look pretty either imho.

I have seen others that were similar with adjustable offset angle. They were mounted directly to the end of the arm tube. I believe redboy made one for an arm he made from scratch.
 
DENNYDOG said:
I converted a Pioneer arm with a piece of carbon fiber tube a got from the local hobby store. Effective length was around 12".

It worked very well but I think it would be better with a tapered tube or two pieces of different od tube such as the black widow uses. This is supposed to help reduce sonic vibrations through the arm.

Some people didn't think it would work that well because the horizontal bearing isn't perpendicular to the offset angle as it is with many arms. This may help tracking although most of the arms that have interchangeable s and straight arms are this way from what I have seen. I'm sure I could re-drill the arm but I didn't find it necessary to do so.

5052324801_1a67615cd3_z.jpg


5052324811_1704b3a60f_z.jpg
Click to expand...

That's nice work!!
 
DENNYDOG said:
cube-tube, I would try looking for some other way to deal with the offset angle instead of the contraption on that SME arm. I'm sure it works but looks like it would add a lot of extra weight at the end of the arm. This kind of defeats the purpose of a straight arm which is low mass. It doesn't exactly look pretty either imho.
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My thoughts exactly. thats a lot of hardware to be hanging out there over the end.
 
This is a interesting idea. If you are a DIY type try it and let us know how it went. Replacement arms for the 1200 are pretty cheap. You could but one and try it before you tear into your TT....
 
I don't get why this turntable homophobia of preferring always the "straight" type...

The arm on the PL-2/4/6 pioneers of the '80s is a good arm, that's an interesting transfornation.

If it was my arm, though, i'd rather wrap the arn in headshrink tubing rather than switching arm pipes.
 
I was also looking at designs like this other RS Labs headshell... But I think this will be beyond my capabilities.
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OR even going this route. Using two of these to make one angle adjustable one... Should be very simple to do with the help of a dremel.
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IIRC, CF arrow shafts are tapered, at least I think I read that here or at VE. For headshells, alot of BPC turntables from the 80's used straight arms with ADC type plug-in shells with appropriate offset angle for their specific length. You could likely pick one up cheap on CL and cut it up for your purpose.
 
Just curious, but why are you doing this? Is there a difference in playback between the two generally speaking?
 
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