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REX



REX
Balanced Preamplifier






Balanced Audio Technology proudly introduces the REX preamplifier, a
revolutionary successor to its highly regarded reference VK-51SE. REX not
only sets a new standard for a reference line-stage preamplifier, it redefines
the critical importance of a preamplifier to achieving great sound.



Design Highlights:

Reaching a new and once-inconceivable plateau in preamplifier state of the art required
Balanced Audio Technology to re-evaluate and fundamentally change existing design approaches.

REX is not just a preamplifier with an external power supply - for this conventional partition suffers from
several well known drawbacks all resulting from the remote placement of the power supply. REX is a
very different beast altogether, with its low-impedance power supply directly connected to the critical
gain block. This novel approach also preserves an upgrade path for the owner of the VK-52SE to REX.

Indeed, REX takes the Balanced Audio Technology tradition of massive and non-conventional power
supplies to a level far beyond any previous Balanced Audio Technology design. For this king of
preamplifiers, BAT designed each box to contain the complete power supply for one polarity positive
in the Control Module, negative in the Power Module. The REX approach to a two-box preamplifier is
balanced design taken to a new extreme, with each individual power supply similar in size to that found
in many power amplifiers. Both modules maintain true dual-mono architecture, of course.

The ten-tube Power Modules supply gets its raw power from vacuum tube rectifiers. The DC voltages
then undergo several steps of filtering including the use of C-multipliers and AC Shunt regulators to
minimize low-level power supply noise. The final stage of filtering incorporates BATs newest custom
oil capacitors. The same capacitors are also used in the Control Modules SUPER-PAK
TM
.

The extreme performance of the REX power supply works in conjunction with a high-current differential
gain stage, composed of four 6H30 SuperTubes per channel, all supported by vacuum tube current sources
(located in the Power Module). The current sources can be customized to tailor the sound to the
customers needs. The gain stage continues the tradition of Balanced Audio Technologys Unistage
TM

approach that incorporates only a single gain element with no buffers or followers to preserve the purity of
sound, and no global negative feedback employed. REX takes the ultimate simplicity of the Unistage
TM

topology to a new level by backing it up with an innovative power supply of extreme heft and purity.

The REX volume control provides a broad range of adjustment with 140 steps of .5dB resolution,
resulting in an essentially continuous feel. Based on shunt topology and using a 16-bit digital control, it
utilizes Vishay Bulk Metal
�
foil resistors as its pass-through devices. Finally, custom oil-filled
capacitors are used at the output, resulting in an unmatched transparency and clarity of sound.

This whole package utilizes Balanced Audio Technologys powerful user interface that allows
customization of each input individually, and continues to receive universal acclaim from customers and
reviewers alike. Like all Balanced Audio Technology preamplifiers, REX can be ordered with an
optional full function remote control. Custom-tailor your sound:

REX incorporates a unique feature that allows the user to optimize its sound, tailoring it to ones
individual taste or system requirements.

The vacuum tube current sources incorporated in REX, being part of the signal gain stage, have a direct
impact on the units sound. Changing the tube type used in that circuit, allows the user an extra degree of
control over the final sound achieved.






In its standard configuration, the REX
current sources use the Russian 6C19 tubes.
This tube is basically a miniature version of
the famous 6C33 tube, and provides, in our
view, the best combination of sonic
characteristics and electrical performance.

However, the unique design of REX allows
you to also use other tube types as current
sources. Currently (no pun intended), the
user has the following three choices for
vacuum tube current sources:

1. The standard 6C19 tube current source (installed at the factory).
2. The 6H30 SuperTube current source (which requires the purchase of the X-PAK accessory).
3. The 5881 tube current source.

In order to change the tube type, the user needs to remove the installed current source board, replace
it with either another board (designed for a particular tube type), or install the 5881 tubes as a direct
plug-in.

Summary:

REX is an eighteen-tube powerhouse that combines simplicity with authority to establish a new
pinnacle in line-stage preamplification.


Specifications

Inputs:




5 XLRs
Outputs:
Main:


2 XLRs


Tape Out


1 XLR
Maximum Gain:



17dB
Global Feedback:



None
Volume Control Resolution:

.5dB
Volume Control Number of Steps:

140
Frequency Response:


2 Hz to 300 kHz
Input Impedance (minimum:)

100kOhm
Output Impedance



200 Ohm
Noise (unweighted):


-100 dB
Distortion at 2V output:


.005%
Maximum Output Signal:


50V
Absolute Polarity:



Switchable
Tube complement:
Control Module
8 6H30



Power Module
2 5AR4, 4 6C19, 2 6H30, 2 6C45
Power Consumption: Control Module
220VA



Power Module
250VA
Dimensions




19 x 5.75 x 15.5 (each module)
Weight

Control Module
40lb




Power Module
36lb




1300 First State Blvd., Suite A

Phone 302-999-8855


info@balanced.com
Wilmington, DE 19804

Fax 302-999-8818


www.balanced.com