ULTRACRAFT AC-400 MK-II (01) PDF MANUAL

(1) The turntable base should be as heavy and solid as possible, and should have a minimum thickness of 15 mm (0.59″).

(2) Mark the mounting position for the tone arm base, using the enclosed mounting gauge.

(3) Drill a 27 mm (1.06″) hole at the mounting position you have marked.

(4) Insert the arm base into the hole and fix it to the base firmly with the washer and lock nut.

(5) Connect the output cable to the plug of the arm center shaft.

(6) Insert the arm center shaft into the arm base and fix it firmly in place, using the locking screw. MK-II series tone arms have two locking screws. Tighten screw A first and then tighten screw B, after having determined the arm height.

(7) Slide the weight assembly onto the shaft located at the rear of the tone arm. When you feel one or two clicks, and when the weight assembly moves forward when it is turned counter-clockwise and backward when turned clockwise, installation has been completed.

This tone arm is a single-point support type, and uses silicone oil to provide viscous damping. The silicone oil provided should be injected in the following manner: The optimum amount of oil (0.3cc) is indicated by the red line on the syringe. The tone arm will not function properly if more or less than this amount is used. In particular, if excessive oil is used, it will either leak, impair proper tracking performance, or result in other problems, such as poor electrical contacts.

To prepare the syringe and oil:

Draw oil until the level is slightly above the red line on the syringe. The cap of the silicone oil container consists of two parts: the upper cap is of the screw-fit type, and the lower cap is of the pull-out type. Allow the oil to settle in the lower part of the container and then draw approximately 0.3cc of oil up into the syringe. Silicone oil has a high viscosity and cannot be drawn into the syringe as easily as low-viscosity fluids. Insert the tip of the syringe into the oil, and pull the plunger of the syringe upward. The oil will then start rising slowly into the syringe barrel. The scale of the syringe has figures inscribed on it: 20, 40, 60, etc. 20 represents 20 milliliters or 0.2cc and 40 represents 40 milliliters or 0.4cc, etc. A certain amount of air in the form of tiny bubbles will inevitably enter the syringe and, for this reason, oil should be drawn in until the level is slightly above the red line in order to allow for the approximate volume of indrawn air.

Injection steps:

(1) Remove the damping control knob on the center block by turning it to the left.

(2) Remove the cap of the silicone oil container (as described above).

(3) Wipe off any oil adhering to the tip of the syringe and press the tip against the oil injection port (which has been exposed by removal of the damping control knob as described in (1)). Holding the syringe vertically, apply pressure to the plunger to force the oil into the center block. As you do so, lift the center block upward slightly with your other hand. This will create a space between the oil cup and oil bowl of the center block, facilitating entry of the oil. If any oil now adheres to any part of the center block, wipe it off thoroughly by using a cotton swab or other suitable implements.

(4) After the injection of the oil has been completed, replace the damping control knob on the center block, and screw it in until it locks into position.

(5) When the damping control knob has been locked into position, the gap between the oil cup and the oil bowl is its maximum. This will enable smoother and quicker settling of the injected oil. Avoid moving the tone arm for about 15 minutes after the oil has been injected, in order to allow the oil to settle.

Note: Once the silicone oil damping fluid has been injected, avoid turning the arm on its side or inclining it excessively to one side or the other. This might cause the oil to leak from the oil cup, which would impair tracking performance or result in poor electrical contacts.

If excessive oil has been injected or if oil should leak because of inclination of the tone arm, refer to the section on “Replacement of damping oil”.

Mount cartridge in the headshell as illustrated in the manual. To ensure optimum performance, overhang should be 15 mm for the AC-300 MK-II and 13mm for the AC-400 MK-II.

When you plug the connectors from the tone arm onto your cartridge pins, observe the following color code:

Green… R minus (R-, RG)

Red… R plus (R+)

White… L plus (L+)

Blue… L minus (L-, LG)

Mount cartridge on the proper position. AC-300 MK-II overhangs 15mm, and the AC-400 MK-II overhangs 13mm.

Note: “overhang” is the distance that the cartridge stylus extends past the center of the turntable spindle when the arm is swung directly over the spindle.

With the standard counterweight mounted on the tone arm, cartridges weighing from 6 to 10 grams (without headshell) can be balanced. With the addition of the auxiliary weight (included in the tone arm package), a maximum cartridge weight of 12.5 grams can be balanced. When the standard counterweight is replaced by the optional AW-5 counterweight, a maximum cartridge weight of 16 grams can be accommodated.

(1) Temporarily disable the anti-skating compensation by rotating its lever clockwise until it clicks into locked position (approximately 10 o’clock).

(2) With the “0” gram mark on the counterweight lined up with the white line of the shaft on which it travels, slide the counterweight back and forth until the tone arm (with cartridge installed) balances horizontally, parallel to the record surface.

(3) When you now rotate the counterweight clockwise on its shaft, the stylus force will correspond to the increments shown on the counterweight.

(4) Release the anti-skating compensation lever.

A major feature of this tone arm is that the amount of silicone oil damping can be adjusted to match the characteristics of any cartridge so that optimum performance may be obtained.

• Turning the damping control knob at the top of the center block all the way to the right until it locks will bring the white dot on the knob to the right position. This is the position that provides the least amount of damping, the LIGHT damping position, and is suitable for cartridges with very high compliance and very light tracking force requirements (approx. 0.75 to 1.25 grams).

• Turning the damping control knob one turn to the left (so that the white dot makes one full-turn), sets the damping at the NORMAL damping position. This position is suitable for cartridges that use tracking forces of about 1.25 to 2.5 grams, particularly moving-coil-type cartridges.

• Turning the damping control knob still another full-turn to the left sets the damping at the HEAVY damping position. When using cartridges with tracking forces of three grams or more, set the damping control knob to this position. When set to this HEAVY damping position, the gap between the oil bowl and the oil cup is virtually zero; there is little more than a thin film of oil between the two components. The damping control knob cannot be moved any further to the left than this.

This tone arm is a single-point support type, so its lateral balance will vary according to the weight of the cartridge. After oil injection, arm height setting and other adjustments have been made, adjust the lateral balance in the following manner:

(1) Turn the damping control knob all the way to the right, to the LIGHT damping position. This will make it easier to balance the tone arm laterally.

(2) Balance the arm horizontally. Keep the anti-skating compensation lever locked for easier balancing.

(3) Apply light pressure to the right and left sides of the damping control knob with the tip of a matchstick or toothpick. If the tone arm tips to both sides more or less equally, then the tone arm may be considered to be roughly balanced laterally.

(4) If it appears to be leaning to one side, turn the lateral balance control knob to balance the tone arm laterally. As a check, repeat step (3).

(5) If the tone arm cannot be balanced laterally even when the weight of the balancer is moved all the way to the right or left, fit the sub-lateral weight that is provided to the side opposite to the direction in which the arm is leaning, and then balance the arm laterally. Be sure to readjust the horizontal balance when the sub-lateral weight is used.

(6) After the lateral balance has been adjusted, apply normal stylus force to unlock the anti-skating compensation, and set it to conform to the stylus force.

(7) Place the stylus of the cartridge on the record. Be sure to use a flat, unwarped record. Check to make sure that the cartridge is parallel to the record. If necessary, readjust the lateral balance. (The balance can be obtained by a 1/4 turn of the balancer knob.)

(8) When the balance has been obtained, write down, on the “lateral balance card,” the position of the lateral balancer, together with the name of the cartridge, stylus force and damping position, so that the correct balance can be obtained again when this cartridge is to be used.

The “lateral balance card” is used to record the position of the lateral balancer, along with the cartridge name, stylus force, and damping position. This helps in obtaining the correct balance again when the same cartridge is used in the future.

The card layout is as follows:

POSITIONING OF LATERAL BALANCE ULTRACRAFT, INC.

(1) Keep the anti-skating compensation locked during the adjustment of the tone arm horizontal and lateral balance.

(2) After the horizontal and lateral balance and stylus force adjustments are completed, unlock the anti-skating compensation.

(3) The position of the compensation weight should be correlated with the stylus force selected. The front of the weight should be aligned with the notches, which are marked for 1, 1.5, 2, 2.5 and 3 grams from the base of the rod.

(4) After adjusting the lateral balance, the inside-force canceller should be adjusted to the proper stylus pressure. The tracking force scale ring should be adjusted so that the desired tracking force is lined up with the pointer inscribed on the weight rod.

The maximum arm lift can be adjusted by turning the ring at the upper end of the cylinder to align the height of the lifter with the height of the tone arm, which varies according to the amount of damping.

The viscous damping silicone oil has a useful life of anywhere from two to three years and need not be replaced during this period. However, if excessive oil has been injected inadvertently when assembling the tone arm, all the oil injected must first be removed and then the correct amount of 0.3cc of oil should be injected. The oil should be replaced in the following manner:

(1) Remove the damping control knob.

(2) Remove the three screws on the upper surface of the oil bowl.

(3) Now fit the damping control knob into the oil injection port once again, screw it in two or three turns, and then lift it up. The oil bowl will come off to reveal the oil cup.

(4) Remove all of the oil adhering to the oil cup and the oil bowl using cotton swabs or similar implements.

(5) Now fit the oil bowl back in position reversing the sequence described above. In doing so, secure the oil bowl in position with the red dot on its upper surface aligned with the shaft of the tone arm.

Damping oil information:

A high-purity silicone oil is used for damping. The standard is AO-20 (viscosity: 200,000 cs). Available as options are AO-30 and AO-50, which are higher in viscosity, and AO-10, AO-5 and AO-1, which are lower in viscosity. The silicone oil is less subject to variation in viscosity when the ambient temperature changes than other organic oils, but the index of variation is 1.75 at 0°C as compared with 1.00 at 25°C. During the cold winter season, the damping oil may be subject to some change in viscosity, and it is recommended that you use one of the low-viscosity oils if the tone arm is to be used in an unusually cold room. AO-20 oil, however, should be suitable in most cases.

Optional Damping oils and their viscosities:

• AO-20: Standard type (viscosity unit: 200,000 cs)

• AO-1: (viscosity unit: 10,000 cs)

• AO-5: (viscosity unit: 50,000 cs)

• AO-10: (viscosity unit: 100,000 cs)

• AO-30: (viscosity unit: 300,000 cs)

• AO-50: (viscosity unit: 500,000 cs)

The arm stems are of the plug-in type and a proper arm can be selected for use with the cartridge to be used. (Refer to the section on “Optional parts” for further details.)

(1) Turn the lock-nut on the center block base side to the left (counter-clockwise) and pull out the arm stem to remove it.

(2) When plugging in, turn the lock-nut to the right (clockwise), exerting care not to bend the contact pins.

Specifications are subject to change without notice for improvements and modifications.

Arm stems:

• SP-S: 6G standard straight type (with non-detachable headshell) for AC-300 MK-II

• SP-S/10: 10G straight type (with non-detachable headshell) for AC-300 MK-II

• SP-300: S-shaped type (without headshell) for AC-300 MK-II

• SP-SL: 8G standard straight type (with non-detachable headshell) for AC-400 MK-II

• SP-SL/10: 10G straight type (with non-detachable headshell) for AC-400 MK-II

• SP-400: S-shaped type (without headshell) for AC-400 MK-II

Counterweights:

• AW-6: For use with AC-300MK-II SP-S (standard type)

• AW-300II: For use with AC-300MK-II SP-300

• AW-3: For use with AC-300MK-II SP-300 (heavy type)

• AW-7: For use with AC-400MK-II SP-SL (standard type)

• AW-400II: For use with AC-400MK-II SP-400

• AW-4: For use with AC-400MK-II SP-400 (heavy type)

• AW-5: Sub-weight

Headshell:

• AS-3PL: Perfect-lock type for use with AC-300 MK-II SP-300 or AC-400 MK-II SP-400

• AS-2PS: 2-lock pins type for use with AC-300 MK-II SP-300 or AC-400 MK-II SP-400

Arm base:

• AB-6: Helicoid base

Output cables:

• ARC-T: 1.5m (59″) standard type (low capacitance cable)

• ARR-T: 1.5m (59″) (low resistance cable)

(Note: Optional damping oils are listed in the “Replacement of damping oil” section.)