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Old 5th August 2012, 01:59 AM   #491
bgruhn is offline bgruhn  United States
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Join Date: Feb 2008
Location: Medfield, MA, USA
Terry,
Check back for earlier postings by dtut (Doug Tuthill). He did his early work with metal tube. 3/4" hard drawn copper plumbing tube should give a well made inner surface. Doug has gone to glass and finds it superior. You can load up an aluminium right angle with a couple of glass slips more easily than milling a copper tube. That stuff is very hard to machine. Aluminium is much easier to machine. The copper does well with abrasive disk cutting. I believe Fran has also used the glass V trough design.

Good idea with the wedge thickness gauge. Looks like we have a couple ways to skin the cat now. Can't think of anything else to order up front. Shop scrap should complete a working model. Were you thinking of 2 thin tubes for the arm or going with a more conventional wood or metal arm wand? For my very first carriage I used 1/4" dia aluminum tube. Had to do quite a bit of damping on that one. I like the looks of a nice hardwood arm wand better than the tubes, but the tubes seem to act better. Can't say how or why yet. Keep us informed please?
Rgds,
BillG

Quote:
Originally Posted by Terry McGee View Post
I'd be tempted to go with a metal tube at first, as I can easily mill the slot. Any recommendations on internal diameter?

2 x $7.99 for the bearings shouldn't break the bank - the postage will probably be as much again! Thanks for that.

Any suggested source for the little connectors that go over the pins on the back of the cartridge. It would be wise to have an ample supply of these. Anything else I need to order up front?

Now, I guess once you make an arm, you need a test disc to evaluate it? Any recommendations for a suitable test disc? (Even if I could find my old one, it hard a hard life back in the days of AM radio. Then again, there might be uncharted territory at the bottom of the groove!)

On the playing weight front, how about mounting the cartridge on an ordinary arm, setting the nominal weight and measuring the clearance under the front edge of the cartridge, then loading up the linear arm (with regard to free-play zone as you had talked about) to give the same clearance?

A wedge style thickness gauge might work well here. You cut a right-angle triangle 10mm high and 100mm long on the hypotenuse, and mark a scale on the hypotenuse. (In this crazy new world, you can probably buy one readymade for less than the materials - anyone aware of such a thing?)

Actually, all we really need is a thin wedge of wood. Mark it with a pencil where it just touches the cartridge bottom on the pivoted arm and aim for that mark on the linear tracker.

Hmmm, my excuses seem to be running out....

Terry
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Old 5th August 2012, 04:22 AM   #492
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Hmmm, maybe I should just bite the bullet and start with glass. Any suggestions on a source, or ideal dimensions? I have some test tubes 18mm OD, 15.65 ID and 150mm long. Might be a bit light on?

Haven't made any decisions on the arm materials yet. I like the triangulation concept for max horizontal stiffness, and I am attracted to metal so it can be earthed, notwithstanding your callous disregard of traditional shielding practice! What length of arm from pivot to stylus are we talking?

Terry
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Old 5th August 2012, 05:47 AM   #493
bgruhn is offline bgruhn  United States
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Hi Terry, I'll have to do a bit of measuring but I think your 150mm test tube might just do the job. Do a quick layout of the 10mm bearing inside a 15.6mm circle to see if it will fit well. Cutting the slot could be difficult but there is a post just a while back dealing with this. I have been touting flat glass strips set in a V. dtut, Fran and myself are all using the V trough configuration. Check my pics again. I cut ordinary window glass (float glass) into strips, 8-9 inches long and 1/4" wide, cheap, readily available, smooth and hard. As to my callous disregard, by the time you get through shielding the wires the drag may stop the carriage cold in its tracks. I'm absolutely amazed that we can get away with twisted wires. We need extremely flexible low drag wires.

Just did a quick measure. 150mm (5.9")won't do the job unless you can make some extenders that slip into the tube say 1/4"and are bonded with epoxy. The arm length on my pen tube taken from stylus to the center line of the bearings is 3 250". I think my last wooden arm was a bit longer. This isn't a critical dimension.
Rgds,

BillG




Quote:
Originally Posted by Terry McGee View Post
Hmmm, maybe I should just bite the bullet and start with glass. Any suggestions on a source, or ideal dimensions? I have some test tubes 18mm OD, 15.65 ID and 150mm long. Might be a bit light on?

Haven't made any decisions on the arm materials yet. I like the triangulation concept for max horizontal stiffness, and I am attracted to metal so it can be earthed, notwithstanding your callous disregard of traditional shielding practice! What length of arm from pivot to stylus are we talking?

Terry
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Old 5th August 2012, 06:39 AM   #494
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Quote:
Originally Posted by bgruhn View Post
I cut ordinary window glass (float glass) into strips, 8-9 inches long and 1/4" wide, cheap, readily available, smooth and hard.
OK, that's sounds pretty easy (at least by comparison to cutting a slot in a tube!) I guess the picture framing shop in the village would be able to do that for me. Less glass would die.

Quote:
As to my callous disregard, by the time you get through shielding the wires the drag may stop the carriage cold in its tracks. I'm absolutely amazed that we can get away with twisted wires. We need extremely flexible low drag wires.
Yeah, I'm a bit amazed too! Hmmm, we have twice the mains volts around here, I guess that means twice the field. Anyway, in the worst case, a balanced front end could deal with any hum I can't avoid. Tempting to use Litz wire. Better HF performance too (cough, cough!).

Quote:
The arm length on my pen tube taken from stylus to the center line of the bearings is 3 250". I think my last wooden arm was a bit longer. This isn't a critical dimension.
Good to have a guide though. That's pretty short, isn't it, so whatever method I choose, we aren't talking a lot of materials, or massive stresses!

Probably the next issue I need to face is what cartridge to run with it. I'm currently running a Stanton 681EEE left over from radio days, but it's pretty uninspiring. (Probably good to experiment with first, as it's pretty indestructible!)

Are there any special characteristics demanded by linear tracking arrangements that I need to consider in choosing a replacement? Or, put another way, does any particular cartridge jump out and scream "choose me!"?

(I'm in the renaissance/baroque/trad folk field, so it doesn't have to deal with anything too difficult. I'm in the market for clarity more than anything else.)

Terry
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Old 5th August 2012, 11:06 PM   #495
bgruhn is offline bgruhn  United States
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Terry wrote:
"Are there any special characteristics demanded by linear tracking arrangements that I need to consider in choosing a replacement? Or, put another way, does any particular cartridge jump out and scream "choose me!"?"

Terry,
The subject of cartridges has come up several times. The general consensus seems to be that most anything will do the job. I'm wrestling with this very topic now. Some of my favourite records are well worn with lots of clicks and skips. The most annoying are the ones I have to get up and push the arm over a tic. Sometimes this can't be avoided, but the same records will play right through with my pivoted arm and even with the same cartridge. On the Cantus clone I get the feeling that very hi-compliance cartridges appear to be the most troublesome. My worst offender is the Signet (AudioTeknica). I recently resurrected an Empire 2000-eIII which was highly regarded when it came out. Had to straighten a bent cantilever and my trouble has diminished almost completely. Am about to buy a new stylus for it. I like the sound and the new stylus is not dear. Also have a couple of ADC XLM-2 carts sans stylus. These came from the same yard sale the Empire came from. XLM = eXtra-lo-mass. These carts get very high marks on the web. So I'm trying to decide if I want to pop for a stylus for the ADC. I don't have pots of cash to throw around on stylii or new carts especially if one of the ones I have will make me happy. I'm not a golden ears type. Also needing
a new stylus are an Ortofon OM40 body that will take a much cheaper OM10/20 stylus and the Signet (pretty hi compliance). Until I can get some real feedback so that I can get a new cartridge with impunity, buying a new cart is out. IIRC there was something about elliptical vs conical tips. I wonder if conical would have any advantage over elliptical with a linear tracker. So, no, nothing jumps out and says "buy ME" . Until we get some better information I would recommend finding something on ebay that looks interesting and you can find some supporting reviews. THE ADC XLM 2 can be had cheap enough as can the EMPIRE-2000E3. Kevin suggests NAGAOKA 100(?) as being a modern low cost cartridge. They can be had for around the $100 mark. Again I don't have that kind of money to play with. Any Cantus users please chime in on this subject please.

BillG
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Old 6th August 2012, 04:38 AM   #496
dtut is offline dtut  United States
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While waiting for Curiosity to drop, I'll jump in here with a bit about carts. I did all my early experiments with a beater Shure M91. I found out later it's a pretty good cart and works well with LTs. There are good, cheap replacement stylii and not-so-cheap up grade or two available. I've mounted an AT95 and 120E, too. Both worked, but I liked the 95 better and it's cheaper. Right now, I'm running a Shure M97xE and I like it, but I'd better explain a little about that. Part of my recent silence has been because I've been building TTs - or at last new plinths for a couple of them. One is a Rek-O-Kut and the other is an Empire. The Empire replinth is the second one I've done. The first one didn't work well with the LT and neither did the Rek-O-Kut. I suspected the first Empire iteration was too resonant and the Rek-O-Kut had an ever-so-slightly out of round idler wheel that seemed to bother the LT. I figured the belt drive Empire platter, bearing, and motor mounted in a solid plinth might be the solution and so far that seems to be true, which brings me back around to the M97xE. I've had the cart for a while and couldn't seem to like it, but in the LT on the solid plinth Empire, it sings beautifully. Before I mounted the LT on the ROK, I was using the original ROK S-120 arm with a Shure SC35C conical stylus DJ cart - beautiful combination. I bought a N35 stylus yesterday which fits the SC35C, but can be run at 1-3 gr. instead of 4-5 gr. like the stock stylus. I will put that combination in the LT and I have high hopes for it. I'll post after I've spent some time with it.

I think LTs, TTs, and carts are another case of horses for courses. High compliance, low VTF looks like a good place to start in a general sort of way, but I suspect the specifics of each set up, and subjective taste, will be the eventual determinants. How's that for a polysyllabic cop out instead of saying "uh, gee, I just don't know."

Regardless, think about how fun we'll have buying and testing carts and stylii - just like the big kids who have pivot arms.
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Last edited by dtut; 6th August 2012 at 04:48 AM.
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Old 6th August 2012, 04:02 PM   #497
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Default carts, horses

And then the pre-amp loading discussion might resume, especially with Shure bits other than the V. Lots of argument over on VE. I just was given a Pioneer integrated amp with switchable phono input, but it skips from 47k to 100k. I may have to try a Denon mc someday. Right now I'm painting my house for the last frakkin time.Got drudgery?
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Old 9th August 2012, 04:41 AM   #498
bgruhn is offline bgruhn  United States
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[QUOTE=Terry McGee;3115375
Are there any special characteristics demanded by linear tracking arrangements that I need to consider in choosing a replacement? Or, put another way, does any particular cartridge jump out and scream "choose me!"?

(I'm in the renaissance/baroque/trad folk field, so it doesn't have to deal with anything too difficult. I'm in the market for clarity more than anything else.)

Terry[/QUOTE]

Hi Terry,
New stylus (cheap one) came in today for the Empire 2000E-3. Setup was easy and it is playing now basically the same style music you are into with some symphonic stuff too. First couple of records were a bit off soundwise but it quickly cleared up and now I'm very pleased with the results. The Empire 2000 so far is very compatible with the LT arm. I don't think you will go wrong getting one of them. Let you know more after using it for a while.

BillG
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Old 10th August 2012, 10:21 AM   #499
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Yes, please. Thanks Bill.

Terry
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Old 11th August 2012, 02:39 AM   #500
bgruhn is offline bgruhn  United States
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Join Date: Feb 2008
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Quote:
Originally Posted by bgruhn View Post
Hi Terry,
The Empire 2000 so far is very compatible with the LT arm. I don't think you will go wrong getting one of them. Let you know more after using it for a while.

BillG
Terry,
Last night I settled in for a listening session with the Empire 2000. Sounded fine but something was lacking. Poor sound stage and overall dullness. Not what I was accustomed to hearing so after a while I remounted the Ortofon OM that I thought needed a new stylus and everything came alive. Sound stage was huge with great detail. Beautiful balance and fullness. This is what I was hoping for with the Empire. So will the Empire beat the 681? I think maybe yes, but if you are buying one, the cost of the more modern, lighter, way better performing, OM10 is only a small amount more. There are lots of vendors on the web that have new OM10s at around the $75 mark. And you can upgrade the OM body by buying only the appropriate stylus. For me, this is one that jumps out and screams BUY ME.

I will be getting a new OM10 stylus soon and should find it tracking at low VTF. The old one is doing great at a bit less than 2 grams. Not having any problem with skips yet. Drags the lightweight carriage with no trouble. So will need to check that with further use.

Rgds,
BillG
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