VAC Kappa 30i User Manual

F

Triode Integrated Amplifier

30i “Kappa”

The VAC Phi Kappa

Operation & Maintenance Information

Valve Amplification Company

Manual issued 05/20/2004

CAUTION

THE AMPLIFIER AND POWER SUPPLY CONTAIN NO USER SERVICEABLE PARTS. DO NOT
REMOVE THE BOTTOM PLATES OR CHASSIS COVERS. LETHAL VOLTAGES ARE PRESENT
WITHIN THE CHASSIS. DO NOT OPERATE THE UNITS IF THEY ARE WET.

VACUUM TUBES BECOME HOT ENOUGH TO CAUSE SERIOUS BURNS. NEVER TOUCH A TUBE
WHEN THE UNIT IS ON. IT MAY TAKE SEVERAL MINUTES FOR THE TUBES TO COOL DOWN
AFTER THE UNIT IS SWITCHED OFF. IT IS STRONGLY RECOMMENDED THAT THE TUBE COVERS
BE LEFT IN PLACE AT ALL TIMES.

THE GLASS COVERS WILL BECOME HOT IN NORMAL OPERATION. DO NOT SET OR SPRAY
ANYTHING ON THEM.

THE AMPLIFIER AND POWER SUPPLY ARE HEAVY. IT IS ADVISABLE TO HAVE ASSISTANCE IN
UNPACKING, MOVING, AND SETTING UP. BE SURE TO USE PROPER LIFTING TECHNIQUES TO
AVOID BACK STRAIN AND INJURY. BE CERTAIN TO INSTALL IT IN A SECURE LOCATION FROM
WHICH IT CAN NOT FALL OR TIP OVER.

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PLEASE READ CAREFULLY

Your Phi Kappa is fitted with a unique output tube monitoring circuit. Rather than directly contacting
the audio path, and thus contaminating the pure sound, the temperature of a small cathode
resistance is sensed. The four bi-color LED’s on the front panel indicate the tubes’ conditions.

If the idle current of a 300B output tube drops below nominal limits, the LED corresponding to that
tube will light green. This indicates that either the bias setting for that tube should be adjusted, or
the tube should be replaced at your convenience, but it is safe to continue operating the amplifier.

The exact idle current of each tube may be tested by means of the meter and the test switches
located on the front panel. The associated bias control should be adjusted so that the needle points
directly at the dot in the center of the meter. When no test switch is selected, the meter indicates
the incoming ac voltage (wall voltage).

Note: These LED’s will also be green when the amplifier is first switched on, and will extinguish when
the bias resistors have reached full operating temperature after approximately 30 minutes. The
threshold between green and no illumination is not precise; do not be overly concerned if some
positions take longer to extinguish. The condition of individual tubes may be checked with the built
in meter.

Note: a strong air current could cause the lights to remain green even in normal operation.

In the event that any output tube draw excessive idle current (a “run away” tube or a tube not
biased correctly), the high voltage supply in the amplifier will shut down automatically and the LED
corresponding to the problematic 300B tube will indicate red. The red light will stay on until the
power switch is turned off. This tube must be replaced. (Note: The LED’s for the other tubes will
show green after a few minutes...this should be disregarded.)

To minimize difficulties, always use genuine VAC Tested audio tubes in your Phi.

Continuous operation of this amplifier is not recommended.

Please turn off when not in use.

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INTRODUCTION

The Phi Kappa is the world's finest integrated amplifier and an absolutely unique component.
Its unusual topology, premium parts, and flexibility make it a pleasure to hear and operate.

Essentially, the Kappa is the combination of elements of the Phi 2.0 preamplifier with the Phi
30/30 stereo amplifier into a single, integrated, optimized system.

The phono stage uses triode tubes operating without loop feedback. Gain is moderately
high, with a very low noise floor. Low output MC cartridges are accommodated by means
of high quality matching transformers, which contribute voltage gain without noise, resulting
in detail that emerges from a remarkably dark and neutral background.

Remote volume control is implemented via a motorized mechanical device. This provides
two major advantages. First, the control is completely intuitive to use. Second, we avoid the
sound degradation attendant with VCAs, transistor switches, and switched resistor arrays.

The power amplifier section uses four 300B tubes in Class A1. These operate in self-bias mode; no
user adjustment is required. Each is provided with a separate DC filament supply to ensure that no
undesirable couplings occur; only the intended ideal signal path exists. The input circuitry is
derivative of the unique Williamson circuit, which provides pure, direct coupled, inherently balanced
input amplification and phase splitting. Type 6SN7/5692 octal twin triodes do the honors.

Two superb VAC output transformers allow high power to be delivered with sonic purity, provide
superb voltage/current translation, and will drive impedances from eight ohms to as low as one ohm.

The main chassis is machined from thick aluminum. The separate power supply allows e.m.f.
fields, switching transients, and mechanical vibration to be isolated from the audio circuits.
The high voltage supply dual choke pi filtering for extremely low noise.

The Phi Kappa is designed not to the latest fad but to substance, for the highest possible
sound quality. Time spent familiarizing yourself with this manual will be well rewarded.

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UNPACKING & ASSEMBLY

The Phi Kappa is shipped with the vacuum tubes and glass covers removed. Should the
need ever arise, the following directions illustrate how to install the glass; follow these steps
in reverse order to remove the glass.

THE AMPLIFIER AND POWER SUPPLY ARE HEAVY. IT IS ADVISABLE TO HAVE ASSISTANCE IN
UNPACKING, MOVING, AND SETTING UP. BE SURE TO USE PROPER LIFTING TECHNIQUES TO
AVOID BACK STRAIN AND INJURY. BE CERTAIN TO INSTALL IT IN A SECURE LOCATION FROM

WHICH IT CAN NOT FALL OR TIP OVER.

Remove the screws that secure the aluminum
top frame to the chassis pillars using the tool
provided. Turn counterclockwise to remove.

Take care to prevent the tool from scratching
the chassis.

Note: tubes should not be installed yet.

Remove the top screws along the back edge.

Remove the top frame.

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From each of the columns remove the tape, which prevented the nylon setscrews from
coming loose during shipment.

Slide the side glass plates into the pillars’
channels.

The glass will not go all the way to the chassis
top, but has a gap at the bottom for air flow.

Take care not to scratch or break the glass

Note: tubes should not be installed yet.

The front glass has the etched VAC logo. Install
this between the front pillars. Take great care
not to scratch this glass.

The front glass fits into a small channel in the
front plate.

Tighten the white nylon setscrews that secure
the side glasses. Turn clockwise to tighten.

There are four setscrews for each glass plate.

Do not tighten the setscrews for the front glass
yet.

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Install the nylon blocks at the top of the side
glasses.
If there is a ‘dimple’ in the block, it should face
the outside of the amplifier.

Tighten the metal setscrews that secure each
block using the allen key supplied. Turn
clockwise to tighten.

Replace the aluminum top frame.

Ensure that the front glass fits into the groove in
the top frame.

Ensure that the top frame sits flush in the pillars.

Replace the rear screws.

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Replace the screws that secure the top frame.
Turn clockwise to tighten.

Tighten the four white nylon setscrews that
secure the front glass using the tool provided.
Turn clockwise to tighten.

Do not over tighten.

Install the vacuum tubes.

The large tubes have two pins larger in
diameter, and can only be inserted one way.
The medium size tubes have a plastic center
pin (“keyway”) that can only be inserted one
way. Do not to break this pin.

The small tubes have a gap in the pins that
matches the sockets, and can only be inserted
one way.

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