Balanced Audio Technology VK-P10 User manual

VK-P10
WARRANTY REGISTRATION FORM
Unit Serial Number: _______________________________________
Customer Name: _______________________________________
Address: _______________________________________
_______________________________________
Date of Purchase: _______________________________________
Purchased From:
Dealer Name: _______________________________________
Address: _______________________________________
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IMPORTANT NOTE:
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 State Blvd. Suite A Wilmington DE 19804 Tel: [phone] Fax: [phone]

VK-P10
Balanced Phono Stage
Owner's Manual
1300 First State Blvd. Suite A Wilmington DE 19804 Tel: [phone] Fax: [phone]

NOTE:
Your VK-P10 Phono Preamplifier was preset at the factory to the following
configuration:
Input Mode: Direct
Gain: High
Input Resistive Loading: 47kΩ
Input Capacitive Loading: None
Please refer to the chapter on configuration switch setting for information on
optimizing the unit parameters.

Introduction
Thank you for your purchase of the Balanced Audio Technology VK-P10 balanced phono
stage. Please read this owner's manual to obtain the full benefit of the VK-P10 in your system. It
will provide you with the needed safety information and operating procedures for this exceptional
unit.
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-P10 Balanced phono stage 1
Power Cord 1
Male Connector Pins 10
Spare Fuse (See Fuse Protection) 1
XLR Input Shorting Plugs 2
Torx Wrench (T-10) 1
Spare Top Cover Screws 5
User’s Manual 1
Optional Accessories (as ordered)
Save all the packaging material in a safe dry area for the unlikely event that you need
to return the VK-P10 to the factory for service.

Reseating Tubes
Normally, reseating tubes upon delivery is not required. However, if any tubes have
noticeably drifted out of position due to unusually high transportation stress, it will be
advisable to reseat the tubes. Use the supplied Torx wrench to remove the top cover.
Reseat the tubes in their sockets and reinstall the top cover.
NOTE: When using the Torx wrench, make sure it is fully inserted so that the screw head is
not stripped.
Physical Placement
It is recommended that you provide for 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-P10 phono stage on top of other units, nor vice versa.
General Description of VK-P10 Phono Preamplifier
The VK-P10 balanced all-tube phono stage is designed to provide the maximum possible
performance while operating in conjunction with the wide verity of phono cartridges available
today. The unit offers unmatched versatility in system configuration by providing the
following features:
• Wide range of user-selectable gains from 44dB to 74dB (See Specifications
section for choices)
• Built-in high-quality step-up transformers that can be used with very low output
phono cartridges.
• Selectable cartridge loading for both resistance and capacitance
• Absolute polarity reversal switch
Please refer to the Configuration Switches section of this manual for information on how to
configure the VK-P10 phono stage for optimal performance in your system.

Connecting the VK-P10 to Your System
Cartridge Input
The back panel of the VK-P10 phono stage is equipped with two sets of input connectors:
RCA input connectors
XLR input connectors
Either set can be used for connection. This gives the user the flexibility in connecting the
phono cartridge cable to the VK-P10. Whenever possible, the balanced XLR inputs should be
used. They provide the best possible performance. Please contact the factory regarding the
best ways of connecting your tonearm to the VK-P10.
NOTE: Connecting to RCA Inputs:
When connecting your cartridge to the VK-P10 RCA inputs, it is necessary to install the
supplied shorting plugs into the unused XLR inputs.
Output Connection
The VK-P10 is equipped with XLR output connectors. Any high quality set of balanced
interconnects can be used to connect the VK-P10 to your balanced preamplifier.
Single-ended preamplifiers can be connected to the VK-P10 output through the use of XLR-
to-RCA adapters, available from BAT.
Description of Controls
Power Switch
The power switch has two positions: OFF and ON. Putting the switch in the OFF position
(even for a short period of time) will reset the soft start and mute circuits. The VK-P10 will
then require about 45 seconds to return back to normal operation.
When you turn the unit ON, the VK-P10 will automatically go through a gentle power-on
sequence. At the end of this sequence the unit will automatically unmute. However, since the
source volume may be unknown at this time, it is advisable to turn the volume control on your
preamplifier fully counterclockwise and place the mute switch in "Mute" position before
turning the VK-P10 ON.

Phase Switch
The Phase switch on the front panel of the VK-P10 allows the user to compensate for
recordings made in inverted polarity. It has two positions: 0
o
and 180
o
. With this switch in its
0
o
position, the VK-P10 performs as a non-inverting amplifier. Switching into the 180
o
position will invert the absolute phase of the signal.
It is important to note, however, that in both 0
o
and 180
o
positions of the Polarity switch
the signal passes through exactly the same signal path elements and components.
Output Muting
The output of the VK-P10 phono stage has a mute relay that disables it for about 45 seconds
every time the unit is turned ON.
When the unit is powered up it automatically self-mutes until the proper operating points of
the circuitry are reached. It will then go into normal play mode.
Changing the power switch position from ON to OFF even for short time, will make the unit
reset its power sequencing circuit and mute its output. It will then require about 45 seconds
for the unit to become operational again.
Configuration Switches
WARNINGS:
Please make sure that the VK-P10 is turned OFF and your preamplifier is in MUTE
before changing the state of any internal configuration switches in VK-P10.
Hazardous voltages are present on the unit’s printed circuit board. DO NOT operate
the VK-P10 with its top cover removed.

This section describes the setting of internal configuration switches that are located inside the
VK-P10 phono preamplifier. In order to access these switches, do the following:
1. Turn the VK-P10 OFF and disconnect the power cord from the power line receptacle.
2. Remove the top cover, using the supplied Torx T-10 wrench.
Figure 1 depicts the locations of the VK-P10 internal configuration switches. These include:
1. Left and right channel cartridge loading switches S101 and S201
2. Direct/Step-Up input mode switches S102 and S202
3. Gain switch S2
The following section describes the operation of these controls.
Cartridge loading switches S101 and S201
Resistance:
The 47K load resistor is permanently connected to the cartridge input. If a different loading
value is desired, it can be obtained by switching in additional resistors, installed on the
VK-P10 PC board. This is accomplished by using the two DIP switches, S101 and S201, that
allow multiple choices for resistive and capacitive cartridge loading. Four positions are
reserved for the choice of resistance and four for capacitance. Out of each group of four, one
position is loaded with female pins and allows the user to install any desired value component
(this position is marked “USER”). Gold-plated solderable pins are supplied with the VK-P10
accessory kit, that should be attached to either resistors or capacitors supplied by the user.
This allows for easy installation and upgrade of user-supplied components.
The following resistors can be added in parallel with the 47K load:
Switch position Resistor Value
1 100 Ohm
2 1K
3 10K
4 User-Defined
Any parallel combination of these values is also allowable.

Capacitance:
Various values of capacitors can be connected in parallel to the input via switches S101 and
S201. With these switches in the OFF position, there is no capacitive loading to the cartridge.
The capacitance choices include:
Switch Position Capacitor Value
5 100pF
6 470pF
7 1000pF
8 User-Defined
Any possible parallel combination of these values is also allowable.
Input Mode (Direct or Step-Up) Switch
The VK-P10 comes equipped with internal step-up transformers, which allow the user to
achieve the best possible signal-to-noise ratio and dynamic range in any system configuration,
including systems with very low output moving coil cartridges (down to .1mV or less).
By changing the position of the S102 and S202 switches, user may choose between Direct and
Step-Up input modes. In Direct mode the cartridge is connected directly to the vacuum tube
amplification stage. In the Step-Up mode the cartridge signal is routed through the
step-up transformer, in order to boost it before it reaches the amplification stage. This allows
for an additional gain of 20dB.
It is recommended that for phono cartridges with the output of more than .25mV, the Direct
mode be used. For sources with lower output voltage, the user should experiment in order to
find the combination, providing the best performance. Using the Step-Up transformers will
usually provide a lower noise floor (see the Specifications chapter).
Gain Switch
By moving the switch S2 from High to Low position, the amplifier’s gain is reduced by about
10dB. While the High gain position provides the most universal setting, it may be desired to
reduce the overall system gain when using some high output phono cartridges.