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Calling Tony L and other DL 103 fans

Nic Robinson

Nic Robinson

Moderator
I'm feeling a bit smug as I fitted my new Denon cart to my Ittok last night without busting either!!

I'm delighted with the way it sounds (thanks for the tip, Tony) but have a question regarding installation.

The nuts supplied are a serrated sort and made it impossible to tighten the bolts very very much. According to Linn-lore the cart should be really tight. Any comments/suggestions?

Cheers,

Nic.
 
The nuts supplied are a serrated sort and made it impossible to tighten the bolts very very much. According to Linn-lore the cart should be really tight.
Click to expand...

They are the normal thread pattern, I managed to find some nuts that fitted. I'd also take Linn-lore with a pinch of salt when dealing with a plastic bodied cart such as the DL103. To be honest Linn's philosophy of tightening cart bolts to such a stupid extent is why about 75% of Ittoks are now totally shagged! A cartridge needs to be bolted to the headshell firmly enough that it can't move or vibrate at all, anything more than that is IMHO simply marketing rhetoric to sell metal bodied carts!

Tony.
 
You won't get it much tighter with all stainless hardware,due to the open mounting lugs being very deep and the body is plastic anyway.

Paul.
 
The level of torque that you can get using a pair of pliers and a small screwdriver is more than adequate. I attempted to use my Rega Cart bolt torque driver and the bolts where just on the verge of squeezing out of the body before the tool had 'clicked', so i backed off. When i first got the Rega torque tool i asked the service dept what it was set to they replied :
The REGA cartridge torque should be set to 0.4Nm, Always turn it for 4 clicks to ensure correct torque.
Click to expand...
0.4Nm is naff all.
When Linn ( or anybody else) mention the famous 'Linn Tight' it would be good if they could give an actual torque figure to give the phrase some real meaning.
 
Nic

I would suggest you use the fasteners supplied with the cartridge. Denon are obviously trying to limit the amount of torque that can be applied, hence limiting the amount compressive load that can be applied to the cartridge body. Using a hexagonal nut will allow you to exceed this limit, probably not a wise move.


Sid

Your statement that 0.4Nm is naff all, is far from being true.
This would produce a thrust of 200lbs, which equates to a stress of 40,000lbs/in2 tensile in the screw. This is very high for screw thread, but I suppose the safety factor is not needed. Nobody will get hurt if it fails.
The main problem is the compressive stress caused by the screw head on the cartridge body. This is 8,000lbs/in2, way beyond the maximum stress for plastic.

Fatcat
 
Fatcat,
Hmm ..OK i suppose the phrase 'naff all' was not the best one. After reading through your excellent reply I decided to go have a look and try to re-fill the hole that has obviously appeared in my memory banks. I think i'll take your word for it ;). It seems there are just too many variables, i also suppose that these variables are more important the lower the actual torque loading is, I mean things like the material the nut and bolt are made from, whether the threads are lubricated, what material is being clamped will depend on the amount of friction underneath the nut and bolt faces , etc, etc . Given its slippery surface you could actually exert more tension in a bolt that was clamping a plastic bodied cart and powder coated arm tube, than say a bare metal headshell and a metal bodied cart for the same indicated torque loading.
One thing i can say is that I have checked out my Rega torque tool using the calibrated strain guage at work and i know it too be pretty accurate, this torque loading definately didn't ' feel' safe when i was tightening mine up, which is why i didn't continue for even 1 click , let alone 4 ! Perhaps these sorts of figures are better suited to metal bodied carts.
i think that try to tighten equally and sensibly seem to be the order of the day, rather than doggedly go for a particular torque loading.

I did start to find this site interesting until i saw the large ugly formulae :p
Torquing stuff
Thanks for your advice anyway, mucho appreciated and something else to think about.
Regards
S&C
 
Sid and Coke

Glad to find that there are people prepared to discuss mechanical engineering instead of all that electronics nonsense. (It doesn’t make any sense to me).
I agree with you regarding there being too many variables to specify a definitive torque setting for plastic bodied cartridges. Chromium plating and reducing the pitch of the thread would increase the load exerted for a given torque.

A few months ago I re fitted an alloy cylinder head to my car. (VW Jetta). The procedure for tightening the head bolts was to use a torque wrench to lightly torque them, followed by 180 degrees rotation. The engineers at VW know the mudulus of elasticity and the poisons ratio of the head, block and bolt materials. They know exactly how much stress, load, compression and elongation takes place to each component.

I would have thought that cartridge manufacturers would be able to give similar instruction. IE, finger tight with supplied screwdriver plus 1 ¼ turns. Maybe even staged tightening.
The number of turns would vary from cartridge to cartridge, as the mudulus of elasticity and the poisons ratio vary from plastic to plastic. The cartridge manufactures must know these properties.

Sid and Coke

I must admit I cheated with the stress calculations. I used to be able to convert torque to thrust from first principles, but not any more. Not as stressful.

Fatcat
Not as stressful
 
Fatcat;
The engineers at VW know the mudulus of elasticity and the poisons ratio of the head, block and bolt materials. They know exactly how much stress, load, compression and elongation takes place to each component.
Click to expand...

How many times had the head been off, before you had your go. Do the same rules apply whether the engine has 1 year and 10,000 'nice' miles under its belt, or 100,000 miles of having it's arse kicked for 10 years. The difference between pressures generated and all them hot/cold cycles surely would make a difference ?

I've got a new timing belt and tensioner spring sitting in the boot of my car, that I've been meaning to replace on my Mazda for about 2 months now. It's gonna happen isn't it ?

Hmm. come to think of it and getting back on target , i don't think I've ever seen any recommended torque values or specific techniques for tightening down cart bolts , from memory most of them say something like " fit bolts loosely, align cartridge , then tighten".
 
Fatcat,

The cart takes a couple of weeks to come and Phono Phono require a fax or jpeg of your credit card and passport. I thought this was a real pain, but I'm pretty sure the cart is a real bargain. It's currently blowing my old Ortofon MC25 FL away (cost £250)

Of course the Ortofon was 5 years old and so the usual disclaimers apply! It's not the first time Tony L and this wonderful forum has saved me big cash. Plus, feeling emboldened to have a go at self fitting has enebled me to learn something and gain much satisfaction.

While I'm on, my Ittok arm lead grub screw was not accessible with a 1.5 allen key, I ended up using a 1.4 screwdriver. Is it possible the allen key has been damaged in the past? I'd take it out for a look if I dared!
 
Originally posted by Nic Robinson
While I'm on, my Ittok arm lead grub screw was not accessible with a 1.5 allen key, I ended up using a 1.4 screwdriver. Is it possible the allen key has been damaged in the past? I'd take it out for a look if I dared!
Click to expand...
I have a feeling it's 1.3 so a 1.4 screwdriver would fit across the widest part. Mine was certainly tiny and 1.5 looks too big on my ruler. I can't check though because I sold it with the arm.

Mick
 
I have a feeling it's 1.3 so a 1.4 screwdriver would fit across the widest part.
Click to expand...

The key for the arm lead on an Ittok is the same size as the one that adjusts the bridge on Shergold guitars, and according to the Shergold site that is 0.050" / 1.27mm.

Tony.
 
I got my dl 103 from Ian Harrison Hi Fi on 01283 702875. It was £90 all in, delivered to my door. I rang him they were in stock at that time,sent a cheque and it arrived about 5 days later.
I love mine it sounds fab on my garrard 401
Clive Smith
 
There you go, then, that's about what I paid from phonophono including p&p so no need to order from Germany.

Cheers for that,

Nic.
 
The DL-103 just keeps getting better - I've had mine a few months now and it is bedded in and sounding stunning, definitely one of the best carts I've owned and a sixth of the price of some...

Tony.

Who's DL-103 is currnetly half way through side 1 of Tanx by T.Rex...
 
Mine's half way through side 3 of Brahms' German Requiem. It's so far only got 20 sides or so on it but I love it! Bargain of the century cart wise IMHO.

Cheers,

Nic.
 
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