Tone arm play?

twice the fun
Post Reply
amagasakii
member
member
Posts: 53
Joined: 18 Jun 2017 04:14

Tone arm play?

Post by amagasakii » 01 Dec 2017 12:20

The tone arm on my 521 has a bit of play in it. As I understand it, all Duals are meant to have *some* play, but I don't know what this actually entails. If I grab the tone arm and pull it front to back or twist it I can definitely feel it move a little, but it's not visible or audible.

Is this something I should look into or should I just leave it alone?

I'm comfortable with the idea of adjusting the bearings, but also worried that I'll ruin a perfectly fine turntable by messing with it.

dualcan
long player
long player
Canada
Posts: 3363
Joined: 15 Nov 2013 23:53
Location: Sorel-Tracy Quebec
Contact:

Re: Tone arm play?

Post by dualcan » 01 Dec 2017 15:07

Hi,
Tonearm bearing are set by touch and back off. That means the pin bearing is brought into the race until there is no slack or play without forcing, then the pin is turned back say 10/20 degrees depending. At that point, there is just enough discernible play in the bearings.
From here on, a horizontal and vertical bearing test should be performed.
Here is the procedure to check both planes:

Vertical test:
1. Set arm for zero tracking force and zero antiskate force.
2. Balance arm perfectly (perhaps without stylus for safety) .
3. * Place arm between platter and rest post, so it can descent. *
4. Drop a stamp on the head (over cartridge).
Arm must descent all the way for the 1200 series, most of the way for 1000 series with tk 12 headshells and at least lower somewhat for 1009, the lower, the better obviously...
If arm moves without hesitation then vertical bearings are ok.
*Note: for the 1219/1229/1229Q, there is a rubber bridge mounted left of and into the rest post, pivoting on a chrome shaft. This rubber bridge can be shifted/removed to enable a proper vertical test.

Horizontal test:
1. Balance arm as before (no stylus-no stamp...)
2. Apply 0.5 anti-skate on any side of the Anti Skate dial under the tone arm.
3. Bring arm towards center of record.
4. Let arm go.
Arm must return all the way back to rest post without hesitation.
If arm moves without hesitation, then horizontal bearings are ok.
That's it for the test.

Regards,
k

amagasakii
member
member
Posts: 53
Joined: 18 Jun 2017 04:14

Re: Tone arm play?

Post by amagasakii » 15 Dec 2017 14:25

Hi Klaus,

Thanks for your very detailed reply! I've done the stamp test and the anti-skate test and passed both with flying colours. There's something slightly satisfying about dialling up the anti-skate and watching the arm dutifully swing in towards the rest post.

(If it wasn't for the smell of nicotine and incense wafting off it you'd think it was brand new.)

I'm sure it's not a great way to check, but my local Sally Ann has had a couple Duals in lately and their tone arms have similar play to mine. I think I'm going to leave it alone. Chances are I'd just mess it up-- if it ain't broke, don't fix it, I guess.

Just wanted to say, it's really cool to speak to someone who worked for Noresco. I posted over in the "How did you end up with a Dual" thread about my mom's Noresco 1214/amplifier combo. Still remember the black plastic square with the chrome lowercase "n" logo on it on the front of it!

dualcan
long player
long player
Canada
Posts: 3363
Joined: 15 Nov 2013 23:53
Location: Sorel-Tracy Quebec
Contact:

Re: Tone arm play?

Post by dualcan » 15 Dec 2017 14:48

Hi,
Noresco did indeed pay my way for many years, and it was a pleasure to work there.
You reminded me of a special tool I made when Dual cassettes were introduced :
DSC00061.JPG
DSC00063.JPG
The hooked end was used on the (then) newly introduced C901 cassette deck to Help mount the belts.
The "n" from the smaller Noresco name / logo that the receivers had, served as a seal...
At the time we had some clients that wanted to "look and see" the innards of some of these complicated decks that I had just serviced. When these decks came back to me in not quite the same way they left, I decided at some point on making this seal and stamp the seal into sealing wax on a crucial screw. I remember catching some folks that way. We usually redid the work but at least they would be shown that I knew... The worst offenders where usually not the actual clients, but our dealers!
A long time ago- yes indeed!
Regards,
k

DSJR
long player
long player
Wales
Posts: 2347
Joined: 01 Feb 2009 21:29
Location: Suffolk

Re: Tone arm play?

Post by DSJR » 15 Dec 2017 14:53

SOME Duals from the late 70's onwards had very noticeable 'clicking' in both vertical and horizontal bearings which I regarded as excessive. Too much and with the wrong cartridge and you will get a tiny degree of 'chatter' which could affect reproduction quality.

I come at it from an audiophool perspective (and maybe am conditioned accordingly) so apologies, but Klaus' advice will mean properly adjusted bearings to Dual's specs and a long and trouble free life.

amagasakii
member
member
Posts: 53
Joined: 18 Jun 2017 04:14

Re: Tone arm play?

Post by amagasakii » 18 Dec 2017 14:12

Klaus, that wax seal/tool is *great*. Nice detailing on the "waveform" bit of the logo!

The "look and see" type of people are few and far between these days it seems.

DSJR, I'm approaching this from a "wannabe" audiophool perspective. Part of me knows I could adjust the bearings (maybe), but another part of me says to just leave well enough alone lest I b****r the whole thing up!

DSJR
long player
long player
Wales
Posts: 2347
Joined: 01 Feb 2009 21:29
Location: Suffolk

Re: Tone arm play?

Post by DSJR » 18 Dec 2017 17:58

FROM PERSONAL EXPERIENCE!!

You MUST fabricate somehow, a means of undoing the outer tonearm bearing locking screws as these are tightly applied. Looking from the front, it's the left hand vertical pivot and on many models, the adjustment on top of the outer bearing 'cradle' - some had the horizontal bearing adjustment set underneath but not yours... PLEASE DON'T try in the slightest to adjust the inner needle pivots without slackening off the outer lock-nut first!! Adjust both for the tiniest of free play and you can't go wrong...

amagasakii
member
member
Posts: 53
Joined: 18 Jun 2017 04:14

Re: Tone arm play?

Post by amagasakii » 24 Dec 2017 10:10

DSJR wrote:You MUST fabricate somehow, a means of undoing the outer tonearm bearing locking screws as these are tightly applied. [...] PLEASE DON'T try in the slightest to adjust the inner needle pivots without slackening off the outer lock-nut first!! Adjust both for the tiniest of free play and you can't go wrong...
I promise! I have read this thread, which is where I got the notion in my head that I could adjust the bearings in the first place: viewtopic.php?f=37&t=86942#p721325

amagasakii
member
member
Posts: 53
Joined: 18 Jun 2017 04:14

Re: Tone arm play?

Post by amagasakii » 10 Jan 2018 05:58

Just wanted to thank you you helping out a newbie, dualcan and DSJR. I stopped by the [only] local vintage electronics store in town and checked some of the Duals and other decks they had for sale and I'm satisfied the amount of play I can feel in the bearings on mine is acceptable for my needs.

Post Reply