Balanced Audio Technology VK-33 User manual

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VK-33
WARRANTY REGISTRATION FORM
Unit Serial Number:
_______________________________________
Customer Name:
_______________________________________
Address:
_______________________________________
_______________________________________
Date of Purchase:
_______________________________________
Purchased From:
Dealer Name:
_______________________________________
Address:
_______________________________________
_______________________________________
IMPORTANT NOTE:

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In order to receive the full five year product warranty, please
mail this completed form together with a copy of your sales
receipt to Balanced Audio Technology at the address below,
within thirty days of purchase.
Failure to do so will result in the product being warrantied for
one year from the date of manufacture.
1300 First Stat Blvd. Suite A Wilmington DE 19804 Tel: [phone] Fax: 302-999-
8818

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VK-33
Vacuum Tube
Balanced Stereo Preamplifier
Owner's Manual
1300 First Stat Blvd. Suite A Wilmington DE 19804 Tel: [phone] Fax: 302-999-
8818

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TABLE OF CONTENT
INTRODUCTION 4
Package Content 4
Physical Placement 5
Connecting to your system 5
FRONT PANEL CONTROLS 6
VK-33 Power On sequence 6
Turning the VK-33 Off 6
PHASE Button and LED 7
MONO button and LED 7
MUTE button and LED 7
INPUT selection 7
VOLUME knob 7
DISPLAY format 8
FUCTION button 8
DISPLAY Brightness function 9
MUTE function 9
VK-33 PROGRAMMABLE FUNCTIONS 10
Parameter Definitions 11
PROGRAMMING THE VK-33 11
BALANCE adjustment 11
VOLUME offsets 12
PHASE 13
MONO/STEREO 13
MAXIMUM gain 13
FIXED gain 14
DISPLAY MODE 14
INPUT NAME 15
REMOTE CONTROL FUNCTIONS 16
Volume Up/Down 16
Mute 16
Fade 16
Input 17
Display/Power 17
Fuse Protection 17
Servicing 17
Cleaning 17
RESETTING VK-33 18
Warranty 19
INTRODUCTION
Thank you for your purchase of the Balanced Audio Technology VK-33
preamplifier. Please read this owner's manual to obtain the full benefit of the
VK-33 in your system. It will provide you with the needed safety information
and operating procedures for this exceptional unit.

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WARNINGS:
To prevent the possibility of serious injury, electrical shock or fire:
DO NOT operate with the cover removed.
DO NOT expose to rain or moisture.
DO NOT defeat the ground power-plug.
DO NOT replace fuse with anything other than the same type and rating as supplied
by the factory.
Package Contents
Included in the box should be the following:
Description Quantity
VK-33 Preamplifier 1
Power Cord 1
Spare Fuse 1
Torx Wrench (T-15) 1
Spare Top Cover Screws 5
User’s Manual 1
VK-R3 Remote Control (If ordered)
Save all the packaging material in a safe dry area for the unlikely event that
you need to return the VK-33 to the factory for service.

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PHYSICAL PLACEMENT
It is recommended that you provide at least 6" of free space around the unit for
proper ventilation.
Mount the unit on a hard surface with proper ventilation underneath.
Do not stack the VK-33 preamplifier on top of other units, nor vice versa.
CONNECTING THE VK-33 TO YOUR SYSTEM
Balanced Components
Use balanced XLR interconnects. All input and output connectors are clearly
marked on the back panel.
Note: The VK-33 XLR connectors are wired as follows:
Pin 1: common/shield
Pin 2: positive
Pin 3: negative
For the VK-33, use the Main 1 XLR Output for connection to your balanced power
amplifier. The Output 2 is configured as an RCA connector output.
Single-Ended Components
Single-ended components have RCA connectors. The VK-33 preamplifier is
designed to work with mix of single-ended and balanced components connected
to its inputs and outputs. If more single ended components need to be
connected to the preamplifer, then the XLR inputs or outputs can be used for
that in conjunction with RCA/XLR adapters. These adapters are available from an
authorized Balanced Audio Technology dealer at a nominal charge.
Two types of adapters are available:
Input Adapters: RCA Female to XLR Male
Output Adapters: RCA Female to XLR Female.

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VK-33 FRONT PANEL CONTROLS
STANDBY Button and LED
The Standby button is used to turn the unit ON and OFF and to switch the
preamplifier into its Standby mode. The LED indicates the status of the unit’s
power circuitry and has four state:
LED OFF Display OFF Unit is in OFF state
Display ON Unit is in ON state
LED Flashing Unit is going through its Power-ON routine
LED ON Unit is in its STANDBY mode
When the unit is plugged into a power line, it will stay in the OFF state until the
Standby button is pushed. The LED will then start blinking and the unit will go
through a 50second warm-up sequence. At the end of that sequence it will turn
ON.
Pressing the button again will switch the unit into its Standby mode.
The VK-33 can be turned OFF by pressing and holding the Standby button.
VK-33 Power-On sequence:
When you turn the VK-33 On, it will automatically go through a gentle power-on
sequence. This sequence takes 50 seconds, during which time the display and
the Standby LED will be flashing, indicating the status of the unit.
1. The number on the display during this time indicates the volume setting.
This will usually start at 000. This setting can be changed during this time
by using the volume knob or Volume Up/Down buttons on your VK-R3
remote control transmitter. In addition, such functions as Phase, Mono,
input selection and Mute can be changed during this time either from front
panel or through the remote control.
2. Normally the VK-33 will be not muted (Mute LED on the display is OFF) and
will begin playing at the end of the 50 second delay. If so desired, the unit
can be put in the MUTE mode during this delay interval either by depressing
the front panel MUTE switch or by using the MUTE button on the VK-R3
remote control transmitter.
Turning the VK-33 Off:
The unit can be turned OFF by pressing and holding the Standby button. It will
automatically mute.

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PHASE button and LED
This button allows the user to invert the absolute polarity of the signal to
compensate for some recordings that are made out-of-phase. The LED indicates
whether the unit is in its INVERTING or NONINVERTING mode. This function is also
accessible via the VK-R3 remote control.
LED OFF Non Inverting operation
LED ON Inverting operation
MONO Button and LED
The Mono button allows the user to switch the VK-33 in Mono operation when the
two channels are summed together. This may be useful, for example, while
listening to old monophonic recordings. This function is also accessible via the VK-
R3 remote control.
LED OFF Stereo operation
LED ON Mono operation
MUTE Button and LED
The Mute button disables the preamplifier output. It is recommended that the
Mute be engaged any time the signal cables are changed or any other system
configuration changes are being made. This function is also accessible via the VK-
R3 remote control.
LED OFF Unit in Play mode
LED ON Output Muted
INPUT selection buttons 1through 5
These allow the user to select any of five available inputs to be played. The
selected input number together with its name will be indicated on the unit front
panel display as well. This function is also accessible via the VK-R3 remote
control.
VOLUME Knob
This knob performs different function depending upon the unit’s mode of
operation. In normal mode it works as volume control knob.
It is also used as a data input device in various Function modes to program the
unit. For example, it is used to set the BALANCE adjustment when the VK-33 is

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switched into its Balance mode. More on that in the corresponding sections of
this manual.
The volume control knob on the VK-33 is linked to a digital encoder and is of a
continuously rotating type (there are no stops).
DISPLAY FORMAT:
The VK-33 Vacuum Fluorescent Display (VFD) is capable of showing up to twelve
alphanumeric characters. Its format depends on the mode of operation. In the
normal PLAY mode the display has the following format:
1. One character indicating the selected input number.
2. Four-character input name. That name is fully programmable (See the
programming functions) and can include up to four character from the
Latin, Cyrillic or Greek alphabets or digits.
3. Balance adjustment indicator. Characters L or R indicate that the balance is
shifted in the corresponding direction. A BLANK character means that the
gains of both channels are identical.
4. Volume setting - three digits with the full range of 000 to 140 (See
programming section on Maximum Volume Setting)
FUNCTION Button
This button puts the unit in its programming mode. In addition to its normal PLAY
mode, there are eight programmable functions in the VK-33:
BALANCE Adjustment
RELATIVE VOLUME setting
PHASE setting
MONO/STEREO setting
MAXIMUM volume setting
FIXED volume setting
DISPLAY (Volume) mode
INPUT NAME assignment
Pressing this button while in PLAY mode will switch the unit into programming
mode. Once in the programming mode, pressing the Function button will switch
the unit into its NEXT programmable functions. The unit will stay in the
programming mode until the exit command is issued. To EXIT the programming
mode at any time, press and hold the Function button for about TWO seconds.

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DISPLAY Brightness Function
Changing the Display Brightness: The VK-33 display can be dimmed
or turned completely OFF by simply pressing the DISPLAY button on your
VK-R3 remote control transmitter.
Each press will reduce the brightness of display and LED indicators in steps
from full ON to OFF, and then one press back to full ON. The LED indicators
will dim but never turn completely OFF. With the display OFF, issuing any
remote control command that would normally require a display change (i.e.:
Volume, Input selection, Fade) will automatically turn the display back ON.
MUTE Function:
The VK-33 has two mute modes: manual and automatic. The blue LED above the
Mute button goes ON when the unit is in MUTE state. To MUTE the VK-33,
depress the MUTE button located on the right side of the front panel. Depressing
this button again will return the unit to its normal operation and turn the mute
LED off.
When the unit is powered up it automatically self-mutes until the proper operating
points of the circuitry are reached. It will then automatically go into Play mode,
provided the Mute function was not activated (the blue Mute LED is Off).
Turning the VK-33 OFF even for short time, will make the unit reset its power
sequencing circuit and mute its output. It will then require 50 seconds for the
unit to become operational again.

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VK-33 PROGRAMABLE FUNCTIONS
The VK-33 programming functions allow the user to optimize the unit
configuration for any particular system set up. The flexible programming facility
defines each signal input with a group of user-selectable parameters that are then
stored in the unit’s memory. Every time a particular input is selected, its unique
combination of parameters is loaded into the operating memory. Programming is
easy and is accomplished through using just two front panel controls -: the
Function button and Volume knob, or corresponding remote control buttons
(Function and Volume Up/Down buttons).
Every unit comes from the factory with a default set of parameters stored in its
memory. This set of parameters is usable for many applications. The default set
includes the following parameters:
BALANCE ZERO
RELATIVE VOLUME ZERO
PHASE Non-Inverting
MONO/STEREO STEREO
MAXIMUM VOLUME 140
FIXED GAIN OFF
DISPLAY COUNTS
INPUT NAMES 1 TAPE
2 TUN
3 CD1
4 AUX1
5 AUX2 or PH1 if the phono card is
installed
The user may at any time, configure the unit to a particular set of system
requirements. For example, input names can be changed to reflect a given
system’s source configuration.

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Parameter Definitions:
Every input of the VK-33 is defined with the following set of parameters.
1. Input name (Examples include CD1, DVD1, PH-1, VKD5, or any other
combination of up to four characters including the Latin, Cyrillic and Greek
alphabet as well as digits)
2. Balance adjustment – gain shifted Left or Right.
3. Volume offset relative to any other input (to compensate for gross
differences in various sources levels)
4. Phase: Inverting, Non-inverting or Last configuration
5. Stereo, Mono or Last configuration
6. Maximum allowable volume setting for a particular input. This is a
convenient safety feature in some instances.
7. Display mode. This allows the user to switch the volume display to operate
in any of the three modes: relative Counts, DBU (Decibels referenced to
Unity gain) or DBM (Decibels referenced to Maximum gain).
8. Fixed volume mode: this allows any input to be set with a preferred fixed
volume setting, and is usable, for example, in Audio/Video installations.
With this flexibility it is possible, for example, to set the CD input to be Stereo
and Non-Inverting, while the Phono input would be Mono and Inverting.
PROGRAMMING THE VK-33
NOTE: It is important to note here that all the functions described
below are accessible either through the front panel controls or via the
VK-R3 remote control. Therefore, functions like BALANCE, PHASE,
MONO, etc. all can be performed by using the Function button on the
remote control in conjunction with the Volume Up/Down buttons.
BALANCE Adjustment.
Pressing the Function button once will invoke the Balance adjustment mode.
When in this mode, turn the volume control knob (or press the Volume Up/Down
buttons on the VK-R3 remote control) to set the balance to the desired position.
An L or R character will appear indicating that the balance is now shifted in the
corresponding direction.

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Exiting the programming mode by pressing and holding the Function
button will store this adjustment for the selected input.
The BALANCE adjustment for each selected input is also stored when switching to
another input while still in the BALANCE programming mode.
RELATIVE Volume adjustment.
It is quite common to have sources with very different output levels connected to
a preamplifier. In this case, switching between different inputs is usually
accomplished by a large change in volume. The VK-33 allows the user to avoid
this inconvenience by setting volume offsets between different inputs (using ANY
input as a reference).
To program this feature:
1. Select any input that you would like to use as a reference. Play music at
the level you find comfortable.
2. Press the Function button twice. The display will read: VOL 000
3. Switch to a different input. Adjust the volume while playing the music to
the level that is comparable to the reference input level. The display will
indicate the volume offset number. That number can be either positive or
negative, depending upon whether the new selected input is stronger or
weaker than the reference input.
4. Exit the programming mode by pressing and holding the Function
button or by switching to a different input.
Any input volume offset can be programmed at ANY time with respect to ANY
other input.
EXAMPLE:
The CD1 input is used as the reference. Let’s presume that the PH1 input (the
weaker source) is then programmed to play at 20 counts higher. Its volume
offset will then read 20.
The user can later select the PH1 input and using it as the reference, program the
AUX1 input to be 10 counts lower than the PH1 input. Effectively, the volume
offset from the CD1 input to the AUX1 will now become 10.
The user then can at any time verify his volume offset programming by switching
the unit in its VOLUME mode (by pressing the Function button twice) and then
selecting the inputs 3, 4 and 5. The volume offset numbers for these inputs
should then read 0, 10 and 20 respectfully. That means that the AUX1 source
will be played at 10 counts above the CD1 input and the PH1 input at 20 counts
above the CD1 input.

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Alternatively, the volume offset number can be entered directly, based on your
judgement of volume difference between the two sources. To do that, select the
input, enter the VOLUME programming mode by pressing the Function button
twice, and use the volume knob to set the volume offset number that you deem
desirable. Then exit the programming mode by pressing and holding the
Function Button .
NOTE: A negative number for the selected input indicates that its
gain will be set lower than the gain of the reference input.
PHASE programming.
Select the desired input.
Press the Function button three times. The display will read: PHASE NINV.
Use the volume knob to set the condition to NINV, INV or LAST.
Exit the programming mode by pressing and holding the Function
button .
NOTE: In the LAST mode, the state of the PHASE switch will be the
same as used the last time for that particular input.
MONO/STEREO programming.
Select the desired input.
Press the Function button four times. The display will read: STEREO
Use the volume knob to set the condition to STEREO, MONO or LAST.
Exit the programming mode by pressing and holding the Function
button .
NOTE: In the LAST mode, the state of the Phase switch will be the
same as used the last time for that particular input.
MAXIMUM gain programming
It may be desirable to limit the allowable volume setting on a particular input. To
do this:
Select the desired input

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Enter the MAXIMUM programming mode by pressing the Function button
five times.
Set the display to any desired number that will now represent the maximum
allowable volume setting for the selected input.
Exit the programming mode by pressing and holding the Function
button .
FIXED Gain mode
In some systems (some A/V installations, for example) it is desirable to set a
particular input to a fixed gain, that is then becomes unaffected by the volume
knob. Most often it is required to set the preamplifier gain to Unity (Gain of 1).
The VK-33 allows the user to do so by using its FIXED gain function.
Press the Function button six times.
The display will read: FIX OFF
Enter any desired number for the fixed gain on the selected input (see
below).
UNITY gain for the VK-33 preamplifier correspond to the
following volume setting:
CNTS display mode 100 Counts
DBU 00.0dB
DBM -20.0dB
Exit the programming mode by pressing and holding the Function
button.
DISPLAY MODE programming
The volume display of the VK-33 can be switched to work in any of the following
three modes:

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CNTS: Relative volume counts with the range of 000 to 140
DBU: Decibel readings with respect to unity gain (0dB).
DBM: Decibel readings with respect to maximum gain (20dB)
NOTE: To avoid possible confusion, the SAME display mode setting
applies to ALL inputs. It is not possible, for example, to set one
input to CNTS and another to DBU.
INPUT NAME programming:
The VK-33 allows the user to assign any a custom name to any input. Those
names may include up to four characters. The default names for the inputs are as
follows:
1 TAPE
2 TUN
3 CD!
4 AUX1
5 AUX2 (It will automatically switch to PH1 if the optional phono card is
installed)
Any combination of up to four Latin, Cyrillic, Greek alphabet characters or digits
can be used to name the source. The examples may include:
CD-2, DVD1, JOHN, VKD5, MARY, BOB1, etc.
To program the input name, do the following:
Select the desired input
Press the Function button eight times. The first character of the input name
will start blinking
Use the volume control knob or the remote control Volume Up/Down buttons
to select the desired character. The characters are organized in the following
order: the digits, the Latin alphabet, the Cyrillic (Russian) alphabet, the Greek
alphabet.
Advance to the next character by pressing the Function button once.

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Exit the programming mode by pressing and holding the Function
button .
REMOTE CONTROL FUNCTIONS:
The optional VK-R3 remote control that comes with your VK-33 has the following
functions:
Volume Up and Volume Down control
Mute function
Fade Down/Fade Up function
Input source selection 1 through 5
Phase switch
Function switch
Display/POWER switch.
The following describes these functions.
Volume Up and Down
These two buttons are programmed with variable speed volume change profiles.
The rate of volume change will be slow upon initial pressing of the Volume Up or
Down buttons. Holding the button depressed will cause the rate of change to

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accelerate, allowing for more flexible control when large changes in volume are
required.
Mute
Pressing this button will cause the MUTE function in the VK-33 to toggle between
ON and OFF states. The Mute LED on the VK-33 front panel will reflect the status
of the Mute circuit.
Fade
Pressing the FADE button on the VK-R3 remote control will cause the volume to
smoothly decay over the period of several seconds. This allows for a gradual
reduction in volume, as opposed to the instantaneous MUTE function. This can be
particularly useful during the presentation or demonstration of your equipment.
When the FADE button is pressed, the volume will go down all the way to zero
(000 on display, unit in Mute).
Pressing the Fade button again will cause the volume to ramp back up to its initial
value.
INPUT SELECT:
Pressing any input selection button on the VK-R3 remote control will switch the
VK-33 to that input. All of the set parameters associated with that input will be
loaded at this point.
DISPLAY/POWER switch.
The Display/Power button on the VK-R3 remote control provides two functions:
turning the VK-33 display ON/OFF and switching the power to the preamplifier.
To control the display:
Pressing the display button will change the display brightness.
Turning the VK-33 OFF
With the display in ON state, press and hold the Display button on the VK-
R3 remote control. This function is disabled when the unit’s display is
turned OFF.
Turning the VK-33 ON

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With the VK-33 in its OFF or STANDBY state, simply press the POWER
button on the VK-R3 remote control transmitter.
Fuse Protection:
A blown fuse in the VK-33 is an indication of a serious problem. If a replacement
fuse fails as well, no further attempts should be undertaken. Please contact the
factory for professional service.
The proper fuse ratings are as follows:
For 100-120 VAC Units: 2A 250V Slow Blow
For 200-240 VAC Units: 1.5A 250V Slow Blow
Factory supplied fuses should be only replaced with the same type
and rating parts.
Servicing
The Balanced Audio Technology VK-33 should require no service in normal
operation. Please direct any further service inquiries to the factory.
Cleaning
To remove dust, occasionally wipe the front and top surfaces of your VK-33 with
a damp soft cloth. If fingerprints appear, you may use a mild, non-alkaline soap
solution. Do not use abrasive cleaners, as they may damage the fine finish of the
unit.
RESETTING THE VK-33:
Under certain conditions it might become desirable to reset the internal
microprocessor that controls all the functions of the VK-33.
Doing so will erase ALL user programmed setpoints, and will return the unit to its
factory default state.
In order to RESET the VK-33, do the following:
1. Turn the unit OFF.
2. Disconnect the power cord from the back of the unit.
3. Wait about two minutes.

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4. Press AND HOLD front panel buttons Input #4 and Input #5.
5. WHILE HOLDING the buttons, insert the power cord.
6. Power up the unit normally.