PRO CO SOUND CB-1 PASSIVE D.I BOX

Passive direct box for connection of unbalanced musical instruments
and line-level sources to low-Z balanced microphone input for PA or
recording. Not recommended for speaker-level use. 1/4" (6.35mm) input
(with parallel 1/4" output). Switch for ground lift. Male XLR-type balanced
mic-level output. Uses Pro Co CBT-1 transformer (20k/150 ohm).

Tube-buffered DI-Box DI-1000

The Tube-Buffered DI-Box DI-1000 allows the extraction of all the musical details of
musical interfaces without degrading the sound. This can only be achieved by
providing a very high input impedance to avoid any loading of instrument pickups.This
design approach allows seemingly infinite headroom to preserve the real dynamic range
of the interfaced instruments.A vacuum tube enables all these goals to be achieved
without any compromises in sound quality.The sonic difference between a standard
DI-Box and the Tube-Buffered DI-Box is comparable to the musical resolution difference
between a standard microphone and a studio microphone.One of the best transformers,
the very transparent sounding JENSEN JT-DB-E, was chosen providing complete ground
isolation. The parameters of this transformer, like frequency response, phase response,
group delay and geadroom capabilities, play a vital part in the performance of this DI-Box.
 
Technical Specifications
Input
The signal of the instrument is directly fed to the tube circuit with > 20 MOhms input
impedance to prevent any signal degradation, inevitable in traditional designs.
Buffered Output“
The second stage of the vacuum tube is used to buffer the signal and lower the output
impedance to < 8 kOhms. This unity gain output allows for cable runs of 10 meters
without loosing high frequency information.
Boost circuit
The boost circuit increases the signal send to the output transformer by 15 dB. This may
be useful for instruments with extremely low output, but decreases headroom capability
to 6 Volt rms. Under these circumstances the signal may be clipped, concerning the output
transformer?s signal, which gives you 2nd harmonic tube-like distortion. This distortion
normally does not occur - but is sometimes desirable, being the reason for this special feature.
Unity circuit
The unity circuit feeds a low distortion unity gain signal to the JENSEN output transformer.
This gives the best possible sound quality.
Ground-lift“-Switch
This front panel mounted switch allows complete ground and electrical isolation between the
direct injection box and the console or recording device.
 

Mechanical Specifications
Cabinet 2 mm stainless steel
Front- and rear-panel 1,5 mm stainless steel lasercut and photo-chemically etched
Dimensions 185 x 100 x 40 mm
Vibration insulation 4 high-compliance rubber-elements
Operating Voltage
220/110 V AC, selectable via rear panel mounted switch. The fuse is easily
accessible from the rear panel. IEC mains connector with optional fixture.
Construction details
Double sided glass fibre contacted PCB with 70 mm copper plating. 1% metal film resistors
and the finest polypropylene capacitors are used in the signal path. MIL type Switchcraft jacks
and high performance switches ensure flawless operation. The power supply is optimised via
measurement quality toroid transformer and a low impedance design to ensure the lowest
possible noise. Through a double sided PCB all parts are roadworthy secured. A waterclear
blue LED perfects the aesthetics of the DI box.

Technical Data
Input impedance > 20 MOhm
Output impedance180 Ohm at 1 kHz
Frequncy response 20 Hz - 20 kHz (-0,1 dB)
                             5 Hz - 120 kHz (-3 dB)
THD at 0 dBv  0,06% at 20 Hz
                      0,04% at 1 kHz
                      0,035% at 20 kHz
Signal to Noise Ratio 86 dB
Tube ECC 83/7025 A - military E 83 CC optional
Output transformer JENSEN JT-DB-E
Polarity Pin 2 Hot , AES/IEC -Standard
Max. Input voltage > 30 V peak
 

The AC 275 is an active, phantom powered direct box. Unlike a passive DI where the frequency response of the signal can be altered depending on the connected impedance, an active DI buffers the input signal with an amplifier. This assures that the sound source will reach the mixer balanced and noise-free.

Housed in a cast alloy chassis, the AC 275 supplies two, high impedance, unbalanced 1/4" jacks and one low impedance balanced XLR jack. It operates with battery or phantom power.

Key Features
?	Active direct box
?	Allows a hi impedance unbalanced source to directly feed a low impedance balanced input
?	Flat frequency response
?	Connects guitar pickups, microphones or electric instruments to a recording or P.A. console without audio quality loss
?	Internal pad for speaker level input
?	Operates with battery or phantom power
?	Ground lift switch eliminates typical ground loop problems
?	Rugged, road-proof cast alloy chassis

At dbx, when we do something, we do it right. So when we decided to create our new direct injection boxes, we didnʼt settle for the same old tired approach to direct box design. With our dbx name on the line, how could we? One look at our new dB10 Passive and dB12 Active direct boxes will tell you that these are clearly different. With their bullet-proof construction, and extraordinary audio performance to rival their looks, finally thereʼs a direct box worthy of the dbx name.

Utilizing custom dbx mu-metal-shielded audio transformers, high-quality Neutrik® connectors, and low-noise circuitry preserves the sonic integrity and true characteristics of the signal source. Both boxes include a pad switch that accomodates instrument, line and even speaker level signals. Take even more control of your sound by utilizing the polarity invert switch to set the phase relationship between the direct and mic'd sound.

As a professional, you donʼt have time for interference, so weʼve included a ground lift switch to solve potential hum and buzz problems due to ground loops. And between the combined shielding of the cast metal chassis and the custom-wound transformer, you can be doubly assured of a clean signal free from interference. All of this sits atop a solid, stable footprint, that will keep the box from being dragged around the stage, and the unique contoured underside allows secure stacking of multiple units.

So whether you need to control the level, placement in the mix, or overall characteristics of 4 independent signals or control the gain leveling on a couple of stereo pairs, the dbx dB12 is for you.

• Phantom Powered
• Green LED Phantom Power Indicator
• +48V Phantom Operation
• Low-Noise Active Circuitr

Input: 1 instrument/line/speaker level

Connector: 1/4" jack

Type: Unbalanced, RF filtered

Impedance: 150k Ohm typical

Max Input Level: +20dBu (0dB pad)
+40dBu (20dB pad)
+60dBu (40dB pad)

Thru Output: 1 parallel connection from input jack

Connector: 1/4" jack

Type: Unbalanced, RF filtered

Main Output: 1 line level

Connector: XLR male jack

Type: Balanced

Impedance: 150 Ohm typical

Max Output Level: 0dBu

Transformer: Custom dbx mu-metal-shielded

Frequency Response: 20Hz to 20kHz, +/-2.5dB

Noise:

THD:

Dimensions: 5.82" L X 5.44" W X 2.20" H (148 x 138 x 56mm)

Weight: 1.4 lbs / 0.65 kg

Note: Specifications subject to change without notice.

You're serious about getting rid of all that excess noise on stage, but you've got so many line
instruments you don't know where to start. The ADB-4 from Stewart can take care of all your
high impedance problems. The ADB-4 is 4 active direct boxes, all in a module that only takes
up half a space on your keyboard rack. It's a rugged, durable piece of equipment that packs a
lot of DI power.

? Requires phantom power or 9v battery
? Ground lift switch
? Instrument or speaker level switch
? Transformerless
? Can be used with amp up to 400w
? RF shielding