[net.audio] turntable tone-arm balancing

jd@umich.UUCP (Joseph B. Douds) (05/20/85)

*** REPLACE THIS LINE WITH YOUR NEW CARTRIDGE ***

I just bought a new cartridge, and I'm not sure how to balance the
tone-arm of my turntable now.  The salesman acted like he knew how,
but he obviously didn't.  I don't have my owner's manual either, so
I'm stuck.  Is there a generic method for balancing, or is this 
procedure really specific?

The model is a Technics SL-B2. (I know I should really be worried 
about proper balance with a clunker like that)  It has an S-arm, 
with two weights (one big, one small) opposite the cartridge.

As far as I can remember, the big weight is adjusted until the arm 
just balances, then the anti-skate value is set to the reading of 
the smaller weight, which turns with the big one.  Then the smaller
weight is turned (independent of the big one) until its reading is zero.

I tried this, but when cued, the tone-arm drifts off to the right.
This is corrected when adding weight, but how far do I go? 

Please respond via E-mail, unless you think this would be beneficial
to others.  Thanks much.
					jd

Joseph B. Douds
University of Michigan
Electrical & Computer Engineering

ihnp4!umich!jd
or, jd@umich

ben@moncol.UUCP (Bennett Broder) (05/21/85)

>I just bought a new cartridge, and I'm not sure how to balance the
>tone-arm of my turntable now.  The salesman acted like he knew how,
>but he obviously didn't.  I don't have my owner's manual either, so
>I'm stuck.  Is there a generic method for balancing, or is this 
>procedure really specific?
>
>As far as I can remember, the big weight is adjusted until the arm 
>just balances, then the anti-skate value is set to the reading of 
>the smaller weight, which turns with the big one.  Then the smaller
>weight is turned (independent of the big one) until its reading is zero.
>
>I tried this, but when cued, the tone-arm drifts off to the right.
>This is corrected when adding weight, but how far do I go? 

The correct method of setting up a cartridge is both generic and
straightforward.  The first adjustment to set is cartridge overhang.
This can be set with either a special protractor or with an alignment
gauge supplied by the tonearm manufacturer.  Basically it places the
stylus in correct relation to the tonearm, so that tracking error is
minimized.  (I am amazed at the number of people who neglect this VERY
important operation, degrading the performance of their new
cartridge).  If you can't get a hold of a protractor or the correct
alignment gauge, Mobile Fidelity sells the "Geo-disk", which does the
same thing. (One is also supplied with Telarc's Omnidisc).

The next step is balancing the arm.  Set the calibrated dial to zero.
Also set the control on any antiskating system so no force is applied.
Then move the main counterweight forward or backward until the arm is
level and parallel to the platter.  (The stylus gaurd should be removed
during the entire operation, so be careful)  After the arm is
balanced, use the calibrated control to add the amount of tracking
force recommended by the manufacturer.  If the manufacturer specifies
a range, select a value in the middle or slightly to the heavy side.
Contrary to popular misconception, it is far worse for your records to
track too light than to track a bit to heavy.  If you have access to
an accurate stylus force gauge, you might want to double check that
the correct force is being applied.

Next, set the antiskating.   You can use the calibrated dial as an
approximation (if your arm has one and your application is
non-critical), just set the dial to match the amount of tracking force
you previously applied; but for best results, use a test record.
Telarc's Omnidisc has a band that is excellent for this.  It has a
pair of tones that grow progressively louder, at some point your
cartridge will be unable to track them without distortion.  If the
distortion appears in the right channel first, increase antiskating;
if it appears in the left channel first, decrease antiskating.
If the tonearms drifts to the right when cued, do not be concerned.
It is a fairly common problem, and one that has absoulutely no sonic
impact on record playback.

Finally, if you have a tonearm with a vertical tracking angle
adjustment, set it.  Start with the cartridge body parallel to the
record.  Then raise the arm to narrow the soundstage and make the
sound brighter, lower it to spread the soundstage and make the sound
duller.  It will take a little experimentation to get it right.
(Simple two mike recordings of piano music and very clean violin music
are best for setting VTA)

It may seem like a lot of effort, but remember that the hours you
spend correctly setting up your new cartridge will be repaid with many
hours of good listening.

                                       Ben Broder
                                       ..ihnp4!princeton!moncol!ben
                                       ..vax135!petsd!moncol!ben

ron@brl-tgr.ARPA (Ron Natalie <ron>) (05/21/85)

> The model is a Technics SL-B2. (I know I should really be worried 
> about proper balance with a clunker like that)  It has an S-arm, 
> with two weights (one big, one small) opposite the cartridge.
> 
> As far as I can remember, the big weight is adjusted until the arm 
> just balances, then the anti-skate value is set to the reading of 
> the smaller weight, which turns with the big one.  Then the smaller
> weight is turned (independent of the big one) until its reading is zero.
> 
I used to have an SL-D1 which probably has the same tone arm.
The little weight is not a weight at all, but a scale.  Turn the
rear weight until the tone arm balances.  If your cartridge weighs
less than 5 grams you may have to add weight to the headshell (KLUDGE
but that's what it says in the manual).  Then turn the small scale
so that the 0 is up.  Turn the weight (this will also turn the scale)
until the desired tracking weight is up.  People usually prefer .75 to
1.5 grams.  Then, set the anti-skating control (small wheel not on the
tone arm itself) to the same as the tracking weight.

Esentially this is how you do any turntable.  Some people will claim that
the anti-skate <-> dial is not appropriate and you should actually do
something to test the anti-skate setting.  I don't bother.  Some turntables
have other methods of setting the weight after you get the tone arm balanced.
The EMT broadcast turn table has a small lever that you move and the anti-skate
is a little weight that pulls on the back of the tone arm through a little
guide.  My old Garrard sets the tracking weight by sliding a weight along
the headshell end of the tone arm.  The antiskate was a magnet that you adjusted
a cover over.  It also had a play counter.

> I tried this, but when cued, the tone-arm drifts off to the right.
> This is corrected when adding weight, but how far do I go? 
 
A properly adjusted tone arm will drift back to the start of the record
when not in contact with the record.  Anti-skating pulls outward.  I use this
to back up slightly while cueing by just actuating the cue button several
times.