Applied Research and Technology (ART) Tube PAC Owner's Manual

TUBE PAC

PROFESSIONAL TUBE PREAMPLIFIER/COMPRESSOR

USER’S GUIDE

TTAABBLLEE OOFF CCOONNTTEENNTTSS

Introduction 2
Registration 2
Features 3
Overview 4
Setting Up 5

Unpacking 5
AC Power Hookup 5
Audio Connections 5

Installation 5
Safety Precautions 6
Powering Up 6
Front Panel Controls and Indicators 6

Gain Control 6

Gain Switch 7

Phantom Power Switch 7

Tube Drive/ Gain Reduction Display 8

Threshold Control 8

Slope Switch 9

Speed Switch 9

Phase Switch 9

Output Level Control 10

Bypass Switch 10
Rear Panel Connections 11

Power Switch 11

Input 11

Output 11
Applications 12
Tube Replacement 13
Specifications 14
On-line Information 15
Warranty Information 16
Service Information 16

131-5004-101

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IInnttrroodduuccttiioonn

Thank you for purchasing Applied Research and Technology’s
Tube PAC. You’ve undoubtably noticed that the Tube PAC is as cool
sounding as it looks. After getting familiar with the Tube PAC,
you’ll realize what a great investment you’ve just made. The Tube
PAC may be used everywhere

! Anywhere you need level adjust-

ments (gain or attenuation), and anywhere you need compression

- you’ll be using the Tube PAC. Offering a superb level of sound
quality, the Tube PAC will enhance the sonic textures of your audio
system for years to come.

RReeggiissttrraattiioonn
If you haven’t done so already, please take the time to fill out the
User Registration Card for your purchase. Having you in our data­base allows us to keep you informed of updates, application
notes, and new product introductions. It only takes a moment, and
it will ensure you are constantly up to date with your purchase.

Fill in the following for your future reference:

Date of purchase: ___________________

Purchased From: ____________________

Serial Number: 131-________

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FFeeaattuurreess
The Tube PAC is a unique product. It contains two independent
award-winning circuit designs - one of the finest tube microphone
preamplifiers available and one of the finest optical tube com­pressors available. Developed in partnership with studio and live
sound engineers, the Tube PAC possesses a “sound” that is not
available from any other product on the market - at any price! The
Tube PAC was designed and constructed with the best compo­nents, assuring a lifetime of quiet, reliable performance. The Tube
PAC offers:

- The award-winning A R T “SOUND”!

- Tube-based mic/line preamplifier

- Tube-based optical compressor

- Hand-selected 12AX7a tubes

- VCA-less compressor circuitry = transparent dynamics control

- Unique tube drive and gain reduction metering

- Bypassable compression circuitry

- XLR balanced inputs and outputs

- 1/4” TS unbalanced inputs and outputs

- Custom extruded aluminum chassis

- +48V phantom power

- Phase reversal

- Over 70dB of gain

- Independent input and output level controls

- Detented rotary controls

- Compression and limiting ratios

- Selectable release time settings

- >90dB dynamic range

- Internal power supply

- One year warranty

- Designed and manufactured in the USA

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OOVVEERRVVIIEEWW

The Tube PAC (PreAmplifier/Compressor) is a multi-purpose tool
for audio engineering and recording. Enclosed in a table-top (and
1/2 rack-able) chassis are two independent circuits featuring a
tube-based analog preamplifier and a VCA-less, tube-based
compressor with optical gain reduction control. Used as a mic/line
preamp or as a DI (direct) box, the Tube PAC is designed to work
seamlessly with any recording, sound-reinforcement, or electronic
instrument setup.

A R T’s Tube PAC circuitry is a hybrid design utilizing the latest,
most advanced, solid-state and tube technology. Using a trans­formerless design throughout, the Tube PAC maintains exception­al signal integrity and extremely low noise. The compressor circuit
follows the preamp. While the preamp is always active, the com­pressor may be bypassed.

The preamplifier’s active balanced solid-state input provides
extremely low noise and excellent CMRR. The 1/4” input has a
high impedance, which prevents the loading of any device con­nected to it and makes the Tube PAC perfect for DI or line level
applications. The preamplifier’s second stage 12AX7a tube runs
on a regulated DC voltage providing an additional 40dB of gain.
Our design causes the tube to overload before the input or output
stage. This allows you to manipulate the tube gain to meet differ­ent sonic requirements.

The compression circuit features a VCA-less design and utilizes
optical electronics (Vactrol) coupled with a 12AX7 vacuum tube
gain stage for superior musical performance. The compressor is
soft knee by design. Although it is capable of providing a thor­oughly “squashed” signal, it was designed to excel in areas where
transparent and musical dynamics control is desired. The beauty
of the optical/tube design is its ability to apply heavy amounts of
compression without pumping and breathing like VCA-based
compressors. In many cases you will hear the results of the com-

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pression without hearing the compressor.

SSEETTTTIINNGG UUPP
UUnnppaacckkiinngg
Your Tube PAC was packed with care at the factory. The shipping
carton was designed to protect it during initial shipment. Please
retain this carton for use in transporting the Tube PAC, or in the
unlikely event that you need to return your Tube PAC for servicing.

AACC PPoowweerr HHooookkuupp
The Tube PAC has an internal power supply designed to operate
at 100 to 125VAC, 50 to 60Hz. Units manufactured for use out­side of the United States of America have been modified to com­ply with the required electrical specifications. Under no circum

­stances should the power cable be altered. If the cable becomes
cut or damaged, discontinue its use and have it replaced before
operating the Tube PAC.

AAuuddiioo CCoonnnneeccttiioonnss
Audio connections to and from the Tube PAC are balanced XLR
(Pin 2 Hot (+), Pin 3 Cold (-), Pin 1 Ground) and unbalanced 1/4”
(Tip Hot (+), Sleeve Ground.) We recommend using only high­quality cables equipped with the appropriate connectors.

IInnssttaallllaattiioonn
The Tube PAC may be employed in a number of setups
including:

- Between a microphone and a mixer, digital multi-track recorder,

DAT machine, hard disk recorder, or analog recorder.

- In a mixer’s channel insert points.

- Between a microphone and signal processors.

- Between electronic musical instruments (synthesizers, guitars,
bass, samplers, acoustic instruments with pickups) and
other gear.

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