Balanced Audio Technology VK-250M User manual

VK-250M
WARRANTY REGISTRATION FORM
Unit Serial Number: _______________________________________
Customer Name: _______________________________________
Address: _______________________________________
_______________________________________
Date of Purchase: _______________________________________
Purchased From:
Dealer Name: _______________________________________
Address: _______________________________________
_______________________________________
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-250 Balanced Monoblock
Owner's Manual
1300 First State Blvd. Suite A Wilmington, DE 19804
Tel: [phone] Fax: [phone]

Introduction
Thank you for your purchase of the Balanced Audio Technology VK-250 balanced power
amplifier. Please read this owner's manual to obtain the full benefit of the VK-250 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 fuses 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-250 Power Amplifier 1
Power Cord 1
Spare Fuses 3
Torx Wrench (T-10) 1
Spare Top Cover Screws 5
Owner’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-250 to the factory for service.

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-250 power amplifier on top of other units, nor vice versa.
IMPORTANT NOTES:
To assure reliable operation always turn the VK-250 OFF while making or changing
input or speaker connections. No connections should be made while the
amplifier is ON.
If the VK-250 was turned OFF for any reason, wait at least 30 seconds before
turning it back ON.
Power Connection
Due to the VK-250 amplifier’ high power rating, it is important to assure the good quality
power line connection. If separate circuit outlets are used for the preamplifier and power
amplifier, it is recommended that both circuits be connected to the same phase of the power
line. Otherwise, a high level of hum can be present.
Input Connections
Best results will be obtained when connecting the VK-250 to a balanced preamplifier.
However, the VK-250 is designed to accept either balanced or single-ended inputs.
Monoblock Connection: On the VK-250M Power Monoblock either left or right input can
be used for input connection – either one will produce identical results.

Balanced Components
Use balanced XLR interconnects to connect the VK-250 to a balanced preamplifier. Input
connectors are clearly marked on the back panel.
Note: The VK-250 input XLR connectors are wired as follows:
Pin 1: common/shield
Pin 2: positive
Pin 3: negative
Single-Ended Components
Single-ended components have RCA connectors. The VK-250 power amplifier is
designed to work with either single-ended or balanced preamplifiers connected to its inputs.
All that is required to connect a single-ended preamplifier with RCA connectors to the
VK-250 inputs is the optional balanced to single-ended adapters. These adapters are
available from Balanced Audio Technology at a nominal charge.
Input Adapters: RCA Female to XLR Male
Speaker Connections
There are two sets of high quality binding posts on the back panel of the VK-250 (one for
each channel). These can accommodate a wide variety of speaker cable terminals. You
can use a 7/16” wrench to tighten these binding posts, however excessive force should be
avoided to eliminate the chance of breakage.
Monoblock Connection: On VK-250M Power Monoblock either left or right output
connector can be used for speaker wires, or both, in case of bi-wiring.
External 12V Trigger Input/Output
VK-250 is equipped with the external 12V trigger connectors – Input and Output. To
control the VK-250 the external device must supply the standard 12V signal.
12V Trigger Output connector can be used to drive another device’s input for daisy-chain
operation of multiple units.

Operating the VK-250
Turning the VK-250 On:
The power switch is located on the VK-250 front panel. If VK-250 was turned OFF even for
a short period of time, you should wait at least 30 seconds before turning it back ON. This
precaution will minimize the stress on internal components.
When you turn the unit ON, the VK-250 will automatically go through a gentle power-on
sequence. At the end of a 10 second delay the unit will unmute and become operational.
Front Panel LED Indicators/ Remote Trigger Operation
When the VK-250 is not connected to the external 12V Trigger line, its Blue ON indicator
will turn ON and OFF when the power switch is depressed.
When unit is connected to the external controller via the 12V Trigger line, the condition
of the LED indicators will depend on the state of that control line.
If the external controller is in OFF state (12V signal is not present), then the green Stanby
LED will light upon power switch activation. The unit will alternate between the
Standby and Off state every time the Power Switch is depressed.
When in its Standby mode, the unit will be controlled by the 12V Trigger line. When that
line issues the ON command (12V signal is present) the green Standby LED will go out,
and the blue ON LED will light.

Fuse Protection:
The circuitry of the VK-250 is protected by the following fuses:
1. The main line fuse is located on the back panel. This fuse should be checked if the
front panel LED’s fail to light.
2. Two internal fuses are mounted on each of the two amplifier circuit boards. These fuses
have two green LED’s associated with them. Both LED’s should be lit when unit is ON and
operating properly. Failure of either of these LED’s to light indicates that the corresponding
fuse is open.
CAUTION:
Make sure that the VK-250 is turned OFF and disconnected from the power line
before checking or replacing fuses.
A blown fuse in the VK-250 is an indication of a serious problem. If a replacement fuse fails
as well, no further attempts at servicing the unit should be undertaken. Please contact the
factory for professional service.
Fuse Ratings
The proper ratings for the main line fuse are as follows:
For 100-120 VAC Units: 10A 250V Slow Blow
For 200-240 VAC Units: 7A 250V Slow Blow
The internal printed circuit board mounted fuses are 10A Fast Acting type.
Factory supplied fuses should be only replaced with the same type and rating parts.
Servicing
The Balanced Audio Technology VK-250 should not require service to maintain its high
performance. In case of malfunction, if replacing fuses fails to eliminate the problem, please
direct any further service inquiries to the factory.

Five Year Limited Warranty
Terms and Conditions
1. Limited Warranty
Upon receipt of the attached warranty registration form, Balanced Audio Technology warrants the purchased
product to be free from manufacturing, materials, and workmanship defects for five years from date of original
purchase, excepting vacuum tubes, subject to the following conditions. Failure to return the enclosed
registration form within 30 days from original purchase will result in a warranty period of one year from
the date of manufacture.
2. Limited to Original Purchaser
This warranty is for the sole benefit of the original purchaser of the covered product, and may not be transferred
to a subsequent purchaser of the product.
3. Conditions and Limitations
This warranty is subject to certain conditions and limitations, as follows. This warranty is void and inapplicable
if the product has not been used in accordance with the instructions found elsewhere in this manual, or if it has
been misused or abused, damaged by accident or neglect, or in transport once in possession of the purchaser.
The warranty is also void if the product has been repaired, modified, or tampered with by anyone other than
Balanced Audio Technology or its specifically authorized agents.
4. Remedy
If this product contains a materials, manufacturing, or workmanship defect that cannot be repaired at the
dealership where the product was purchased, it must be packed in original packaging and returned to Balanced
Audio Technology via insured freight, at the owners expense. If replacement packaging materials are required,
they will be supplied by the factory at a nominal charge. Returned products must be accompanied by a
written description of the defect, and a return authorization number (available from the factory via
phone or fax). Upon receipt of defective product, Balanced Audio Technology agrees to repair the product
without charge for parts (except vacuum tubes if the unit is more than one year old), or labor. The product will
then be returned via prepaid, insured freight, with carrier at the sole determination of Balanced Audio
Technology. This constitutes the purchasers sole remedy.
5. Design Changes
Balanced Audio Technology reserves the right to modify its products or change specifications at any time
without obligation or liability to previous purchasers.
6. Miscellaneous
Any implied warranties relating to the above product shall be limited to the duration of this warranty. This
warranty does not extend to any incidental or consequential costs or damages to the purchaser. This warranty
gives you specific legal rights. You may also have other rights which vary from state to state.