Kuzma Stogi S User manual

INSTRUCTION MANUAL
FOR
KUZMA TONEARMS
S T O G I A N D
S T O G I R E F E R E N C E
KAT d. o. o. Kuzma Audio Trade Hotemaže 17 a
4205 PREDDVOR
SLOVENIA tel. [phone] fax [phone]

_________________________________________________________________
STOGI/STOGI REFERENCE 2KUZMA
CONTENTS
I. GENERAL DESCRIPTION 3
II. PACKING LIST 4
III. UNPACKING 4
IV. MOUNTING AND ADJUSTING 5
A. Mounting Tonearm 5
B. Mounting Cartridge 8
C. Tracking Force Adjustment 9
D. Height (VTA) Adjustment 10
E. Tangentional Cartridge geometry adjustment 11
F. Fine VTA Adjustment 15
G. Azimuth Adjustment 16
H. Bias Adjustment 18
I.Fine azimuth Adjustment 19
J. Cueing Device Adjustment 19
V. GENERAL MAINTENANCE 20
VI. MINOR PROBLEMS 21
A. Pin Connector Breaks Off from Internal Wiring 21
B. Broken Bias Thread 22
C. Hum and Buzz 23
VII. TRANSPORT AND PACKING 24
A. With tonearm on Turntable 24
B. Packing (Fig. 29) 24

_________________________________________________________________
STOGI/STOGI REFERENCE 3KUZMA
I. GENERAL DESCRIPTION
The main structure and headshell are both machined from solid aluminimum blocks
while the tube is of specially treated aluminium which is internally damped. The tube
also allows rotation for azimuth adjustment. Stogi reference tonearm has conical tube
with different adjustment.
The quality bearings are carefully selected and individually checked and tested before
assembly. They can each support 20 Kg. and are mounted free of play with minimal
friction in all planes.
Stogi incorporates a number of extra features including adjustable cueing device,
removable finger litf, precisely calibrated counterweight and simply adjustable bias.
The arm is wired throughout with cardas wires or Van del Hul cables and comes
equipped with its own full accessories kit. It will accept all cartridges and can be fitted
most quality turntables.

_________________________________________________________________
STOGI/STOGI REFERENCE 4KUZMA
II. PACKING LIST
1. Tonearm with fingerlift.
2.Counterweight.
3. Base.
4. In small bag:
a) Three socket head screws M5 x 35 mm and three washers for fixing base.
b) Allen keys: 5 mm for attaching base to armboard, 3 mm for height adjustment
(VTA), 2,5 mm for fixing counterweight, bias and cueing device adjustment.
c) Bag containing two headsocket screws M 2.5 x 12 mm and nuts for fixing
cartridge plus Allen key 0.7 mm for removing fingerlift.
5. Two protractors, one for mounting tonearm on turntable and the other for cartridge
geometry adjustment.
6. Instruction Manual.
III. UNPACKING
1. Remove polystyrene cointainer from box.
2. Remove tape from sides and lift top half of polystyrene container (marked TOP).
3. Remove small polystyrene insert.
4. Holding the pillar not tube , lift tonearm in one hand and remove from plastic bag
with other, holding by pillar. Observe bias and thread while so doing.
5. At this stage tonearm can be rested upside down on C shape.
6. Remove all other parts. (See packing List).

_________________________________________________________________
STOGI/STOGI REFERENCE 5KUZMA
IV. MOUNTING AND ADJUSTING
A. Mounting Tonearm
1. Take tonearm mounting protractor and place on spindle of turntable. The cut-out is
similar to standard Linn cut-out. (Fig. 1)
2. Mark position of holes as indicated on protractor on tonearm mounting board.
Ensure that there is adequate space in front for tube and headshell and behind for
counterweight, in order to avoid problems of lid closure. Check also that screw
positions will be over cut-out on subchassis, unless screws are to be sunk. It is wise
before cutting to hold tonearm in position over marks and judge if position of
tonearm on board will be correct, bearing in mind these criteria. (Fig. 2) Otherwise
precise position of tonearm is unimportant providing it lies on protractor arc.The
height of tonearm with cartridge mounted is 55 mm above record. (Fig. 2 a).
3. Remove tonearm board from turntable.
4. Check that thickness of board is between 6 mm and 12 mm, if so make cuts as
marked.
NOTE: If board is thicker than 12 mm
Either a) obtain screws of length that will go through armboard and into base to a
depth of approximately 5 mm, remembering washer or
b) sink the screw heads by first drilling a large hole of about 9 mm with drill and then
drilling hole of smaller dimension through this. (Fig. 3)

_________________________________________________________________
STOGI/STOGI REFERENCE 6KUZMA
5. To fix base to armboard you will need the three socket head screws, spring washers
and Alley key 5 mm. Fit washers on screws and insert into underside of tonearm
board and up into tonearm base. (Fig. 4). Position base so that height adjustment
(VTA adjustment) screw is at top right position, i. e. 2 o’clock and tighten screws
using Allen key. Remember that screws are of harder material than tonearm (steel
and aluminium) so do not overtighten as this could damage base. (Fig. 5)
6. Replace tonearm board on turntable.
7. Insert tonearm cable through hole in base, then the pillar and fix at suitable height
using Allen key 3 mm at height adjustment screw in base. (Fig. 6)
8. Screw on counterweight so that thread is covered. This may take a little time.
9. It may now be necessary to adjust the suspension on the turntable due to the added
weight of the tonearm.
10. Fix tonearm cable onto turntable ensuring that there is adequate cable to allow for
height adjustment. If turntable has a suspended subchassis, position cable in such a
way that subchassis has freedom of movement.
11. The phono plugs are marked in the standard way: left - white, right - red, and
should be inserted into phono inputs. The connector at the end of the grounding
wire should be connected to GND on preamplifier.
12. Check that bias and thread are correctly positioned (it may have tangled during
handling). (Fig. 7)
13. For optimum performance you may wish to forego the convenience of the finger
lift. If so, this should now be removed using Allen key 0.7 mm, loosening screw
and easing out lift. Replace screw in hole. (Fig. 8)

_________________________________________________________________
STOGI/STOGI REFERENCE 7KUZMA

_________________________________________________________________
STOGI/STOGI REFERENCE 8KUZMA
B. Mounting Cartridge
You will need Allen key 2.5 mm plus the two screws and nuts M 2.5.
1. Keeping stylus guard on cartridge, insert screws from undeneath cartridge through
slots in headshell and screw on the two nuts manually. (Fig. 9) The tip of the
cantilever should be level with the end of the headshell (viewed from side).
2. Fix by slightly tightening screws using Allen key. Ensure that nuts have fitted into
ledge around slots.
NOTE: It may be found easier to remove tube from armrest to give a little
more room.
3. Using tweezers, push the pin connectors into cartridge according to code
Red - right
Green - right ground
White - left
Blue - left ground
The connectors will slip snugly onto pins of the majority of cartridges, (Fig. 10)
however:
If pins are too fat with tweezers firmly push connector onto pin. Connector will
open slightly. Do be careful, however, that tweezers do not slip and damage
cantilever.
If pins are too slim then connectors should be squeezed with tweezers to make hole
slightly smaller. First squeeze as in A then as at B then slip connectors onto pins.
(Fig. 11)
4. Put cueing device into ‘play’ position, ie. down, release tube from armrest and
adjust counterweight until tube is balanced ie. floats in a horizontal position slowly
back towards the armrest. Prior to final balancing remove stylus guard. (Fig. 12)

_________________________________________________________________
STOGI/STOGI REFERENCE 9KUZMA
C. Tracking Force Adjustment
The instructions with your cartridge will recommend suitable tracking forces. We
recommend you choose the highest force given and set arm to that amount. A higher
tracking force causes less damage to the record as the stylus maintains more stable
contact with the sides of the grooves.
The counterweight is marked with five red dots. (Fig. 13) One full rotation of the
counterweight increases tracking force by 0.5 grams, therefore distance from one dot
to another corresponds to 0.1 grams.
With the cueing device in the ‘up’ position and tube in armrest the counterweight is
turned anticlockwise (from front view) to increase the tracking force.
As the tonearm is now balanced, the position of one dot should be noted and taken as
zero, (any dot will do so choose the moste easily visible). Then simply turn the
counterweight anticlockwise counting each dot that passes that position as an
increased tracking force of 0.1 gram. For example a tracking force of 1 gram will
necessiate turning the counterweight past 10 dots or two complete turnst the
counterweight.
NOTE: An inaccuracy of a few mm. in the position of a dot is not critical.
Fixing the Counterweight
The counterweight is secured by gently turning one of the three screws M3 with the
Allen key 1.5 mm. Do not, however fix securely at this stage until tangentional
tonearm adjustments are completed.

_________________________________________________________________
STOGI/STOGI REFERENCE 10 KUZMA
D. Height (VTA) Adjustment
(Fig. 14)
1. Put record on platter.
2. Remove tube from armrest with cueing device still in ‘up’ position.
3. Put stylus guard on.
4. Position needle in normal playing position above record with lift still up, to ascertain how
low or high the arm is.
5. If tonearm is too low, then the tonearm must be raised by releasing the screw in the base
while holding the tonearm by the ‘C’ shape and lifting up. (Fig. 15)
6.Tighten screw when tonearm is in position though do not overtighten.
7. Repeat process until arm is high enough to clear record.
8. Remove stylus guard and put cueing device in play position (down). The needle should be
in the groove. If not the tonearm is too high and should be lowered.
NOTE:To ensure needle is properly in the groove observe headshell, cartridge body
and (in standard Stogi) the tube, all of which should be parallel to the
surface of the record. This is more easily seen if the stylus is in
the middle grooves of the record side. (Fig. 14)

_________________________________________________________________
STOGI/STOGI REFERENCE 11 KUZMA
E. Tangentional Cartridge geometry adjustment
Once the cartridge has been mounted, it is necessary to ensure that the cartridge is
tangentional to the record grooves in order to minimise tracking distortion during playing. As
the cartridge moves in an arc across the record, tracking distortion occurs and is minimised
by the tonearm geometry and the angle of the cartridge in the headshell.
With optimum tonearm geometry very low distortion levels (below 1 %) can be obtained
across the entire playing surface. Cartridges have zero distortion at two points on a record
and these points are used when aligning the cartridge. In practise these points lie at 66 mm
and 121 mm from the record centre (see protractor). Other protractors make use of different
zero points due to the use of different parameters in calculation. In this case 60 mm has been
chosen as the inner groove and 146 mm as the outer groove which still has optimum tracking
distortion.
(Fig. 16)
For a distance of 212 mm from record centre to centre of tonearms horizontal rotation the
optimum overhang is 18 mm and the effective length, ie. distance from the centre of tonearm
horizontal to the tip of the cartridge is 230 mm. This is gained with offset angle of 24°, and
gives a maximum tracking error of under 2° and distortion of under 1 %. These are harmonics
of the second order which are not so irritating as the third which are very common in
amplifiers. (Fig. 16 a)

_________________________________________________________________
STOGI/STOGI REFERENCE 12 KUZMA
1. Ensure bias is on minimum.
2. Place protractor over spindle on platter. (Fig. 16)
3. Alignment at zero point 66 mm (A)
Place tip of stylus on point A (ie. zero point 66 mm). With a strong light observe cartridge
from front. The cantilever and the line on protractor (Fig. 17) should be in perfect
alignment.
If the cantilever is not then the body of the cartridge will have to be turned slightly. (Fig.
18)
Do not adjust cartridge by observing body of cartridge only.
HINTS: If you have difficulty seeing the cantilever it may help to raise the arm a
few mm. taking care that the protractor does not rotate. This also prevents
tilting of the cantilever due to the effect of bias force. It may also be helpful
to fix the platter by inserting a wedge between platter and plinth and by
inserting a sheet of white paper to give a clear background while observing
the cartridge.
To Adjust Cartridge
4. Slightly loosen the screws which attach the cartridge to the headshell.
5. Holding headshell in one hand slightly rotate the body of the cartridge.
6. Recheck alignment at position A and continue adjustment until line described in point 3 is
achieved.

_________________________________________________________________
STOGI/STOGI REFERENCE 13 KUZMA
Alignment at zero point 121 mm (B) Fig. 19)
7. Reposition protractor and check alignment at position B in the same vay as in position B.
8. If the cantilever is not in alignment then rotate protractor until it is in alignment
somewhere
along the line ‘x y’ though not necessarily at point B. (Fig. 20) Raise the cueing device.
9. If needle is in front of point B, pull the cartridge forward in the slots of the headshell for
approximately the same distance. If it is behind point B, push cartridge backwards for
distance ‘s’.
10. Now realign at point A as in 5 and 6 above ensuring that the position of the cartridge in
the
slots alongside is not changed.
11. Recheck alignment at point B. If cartridge is not aligned here rotate proractor to find
where on line ‘x y’ the cantilever is aligned. If it is in front as before, but nearer to point
B, then again pull cartridge slightly forward and repeat by aligning at point A. If stylus is
further forward on line ‘x y’ then move cartridge in opposite direction to before, ie.
backwards. (Fig. 20) If stylus is behind the B point, the cartridge should be pushed back.
Realign at point A and then at B.
12. Continue until stylus is in alignment at both points.
REMEMBER: a) align at B by rotation
b) check at B
c) align on line ‘x y’ and move cartridge.
Repeat a, b, c until cartridge is in alignment at both points.
NOTE: Ensure that cantilever is not twisted due to bias force.

_________________________________________________________________
STOGI/STOGI REFERENCE 14 KUZMA
13. Securing Cartridge
The screws holding to the headshell must now be tightened and it is very important
to avoid moving the position of the cartridge, so tighten in the following way:
slowly, one screw at a time in extremely small stages. Before screws are
completely tight check that cartridge is still in alignment at position B and then
at position A.Then tighten screws firmly bearing in mind whether the cartridge
body is made of metal or plastic!
NOTE: If you find it impossible to align the cartridge, ie. the cartridge cannot move
far enough forward in the slots of the headshell, then the tonearm is incorrectly
positioned on the armboard, being too far from the record centre. If the cartridge
cannot be moved far enough back in the headshell, then the arm is too near the centre
of the record.
In either case the tonearm will have to be repositioned on the armboard. It should be
noted however, that different cartridges allow for more or less movement than others.

_________________________________________________________________
STOGI/STOGI REFERENCE 15 KUZMA
F. Fine VTA Adjustment
VTA describes the angle between the record surface and the stylus (Fig. 21). This
angle changes as the height of the tonearm is altered. The standard angle is 15° but
cartridge manufacturers work with degrees of anything between 10°- 30° so only by
listening tests can one ascertain the correct angle for your particular cartridge. The
VTA also varies according to the tracking force and thickness of records. For your
information to change the angle by 1° means a change in height of approximately 3
mm on the pillar. Some styluses need more precise adjustment of VTA than others.
The most sensitive profiles are Van Den Hul and Microridge types.
1.With felt pen mark the position where the pillar meets the base as a point of
reference.
2. Use a good recording, preferably acoustic instruments and listen.
If the tonearm is too low the sound has a tendency to have an overblown base and
the stereo picture is imprecise.
If the tonearm is too high the sound tends to be too bright, ie. too aggressive,
especially on acoustic strings.
3. Try moving the tonearm up for 3 mm and down for 3 mm to judge where the arm
sounds most balanced with more precise stereo picture. (This is similar to focusing
a camera). Fine adjustments can be made in the range of 0.5 mm.
4. VTA can also be altered by changing the tracking force. An increase in tracking
force is equivalent to lowering the tonearm and vice-versa.
5. Now fix height firmly.

_________________________________________________________________
STOGI/STOGI REFERENCE 16 KUZMA
G. Azimuth Adjustment
Normally this is obtained automatically when the tonearm is mounted, providing the lines
(Fig. 22 a) are in alignment.
Rough Adjustment (Fig. 22)
Azimuth describes the angle between the record surface and the stylus, viewed from the front
of the cartridge. This should be 90° and can be checked by observing if the cartridge body is
square with its mirror image on the blank part of a record or by putting a mirror under the
stylus (taking care that the stylus does not slide). If using a mirror ensure that it is absolutely
flat.
Stogi Reference:
If stogi reference the cartridge is not square, the tube can be rotated slightly to obtain the
correct azimuth. Firstly the tube should be released by loosening the two screws on the top of
the arm. (Fig. 23) Use Allen key 2.5 mm and turn screw for only 90°. Then (being careful not
to push the tube off the armrest) insert the Allen key into the screw on the right side of the
arm. (This screw is above the cueing device.) Observing the position of the marks on the
tonearm and the cartridge body in a mirror, this screw should be turned for approximately 45°
to alter the azimuth. A clockwise turn of the screw causes a clockwise rotation of the arm and
vice-versa. When the cartridge body is square fix the top two screws firmly but do not
overtighten as the locking mechanism holds very quickly.
Stogi:
The fixing screw is underneath the tube (Allen key 2.5 mm). Rotate key clockwise for 90°,
then manually rotate tube and fix screw with anticlockwise action.

_________________________________________________________________
STOGI/STOGI REFERENCE 17 KUZMA
Fine Adjustment
This can be done using an osciloscope (see p. 16) or by using good records in a good system
and listening to the sound. Cartridges with fine profiles (VDH, Microline etc.) are more
sensitive to this adjustment. On the other hand cheaper cartridges are not made so well,
making fine adjustment more useful.
Start listening with the tube in zero position, ie. with the marking lines aligned. Listen to the
sound-stage, the focus and the stability of the instruments. Release the two locking screws
and rotate the Allen key so that tube rotates for approximately the width of the mark. Listen
and then rotate tube for a similar amount in the opposite direction and again listen. Ajudst the
arm to the position in which the best sound was obtained. In this position make further
adjustments by turning the Allen key for a quarter turn in one direction, listening and then
turning a quarter turn in the other direction and listening.
Continue this process making ever decreasing adjustments, 1/8 of a turn, then 1/16 and so on.
When optimum results are obtained fix the locking screws.
NOTE: During fine adjustment only gently fix locking screws during listening.
The adjustment screw is highly sensitive and the smallest pressure on the Allen key
will alter the azimuth and sound.
Do not attempt any adjustment when the locking mechanism is locked. Although no
damage can be done.
Significantly improved sound can be obtained by paying attention to azimuth
adjustment prior to final VTA adjustment.

_________________________________________________________________
STOGI/STOGI REFERENCE 18 KUZMA
H. Bias Adjustment
The bias should be adjusted according to the tracking force. Using cartridge protractor
provided you will see marked distance ‘x’ in grams equivalent to the tracking force. Hold
protractor as in Fig. 24. Using Allen key 1.5 mm, until in the position equivalent to your
chosen tracking force. Lock screw when in position.
For maximum trackability, it is advisable to set the bias by use of an appropriate test record,
ie. those with tracking bands. Please do not use test records with blank space where the tip of
the needle sits on the surface rather than in the groove. (Fig. 24 a)
1. Set bias and tracking force as previously described and listen to mistracking on highly
modulated tracking bands. On higher modulated bands mistracking can be heard as impure
tones and there will be more overtones. (See instructions on test record)
2. If mistracking is apparent, increase or decrease bias until minimum mistracking is found.
If mistracking is heard on the right channel only then the bias is too low, if on both
channels the bias is too high or the trackability limit of the cartridge has been reached.
3. Finally further decrease mistracking by increasing tracking force to the maximum
recommended for the cartridge.
4. Again try to optimise bias.
NOTE: Mistracking is most easily observed by use of an osciloscope.

_________________________________________________________________
STOGI/STOGI REFERENCE 19 KUZMA
I.Fine azimuth Adjustment
Using a Dual Trace Oscilloscope
Even if the cartridge body is square there is no guarantee that the generator within the
cartridge is at the correct angle to the cartridge body. With an oscilloscope and test
record which has channel separation tracks, one can measure how much of the signal
from one channel crosses over to the other. This is called crosstalk and is always
present to some extent, but it should be equalised.
Azimuth affects channel separation. If the cartridge is tilted to one side the separation
will be very good on one channel but very bad on the other. Good sonic results are
gained when the separation is equal. Be sure to measure crosstalk only not output.
Readjustment of Tracking Force
It will now be necessary to readjust the tracking force. This can be done using scales,
if available or by rotating counterweight back until tonearm is balanced (with stylus
guard off) and applying the required tracking force as previously described. (IV C) Fix
counterweight as described.
Final VTA Correction
Once the azimuth has been corrected the VTA should be checked. For optimum
performance recheck VTA after 30 - 40 playing hours. This may be necessary due to
‘settling’ of cantilever suspension in the cartridge, the amount of which varies
according to the make of cartridge.
J. Cueing Device Adjustment
Should you find that in the ‘up’ position the cartridge is too high or too low above the
record then the cueing device can be raised or lowered. (Fig. 25) This can be done
simply by using Allen key 1.5 mm.
1. Insert key into screw on left side of arm rest.
2. Release screw, raise or lower device and retighten.
NOTE: The cueing device may lift slightly as the screw is retightened. Do not
overtighten as this may cause the cueing device to stick in the ‘up’
position. Should this occur, slightly release the screw.