RADIAL JDI Passive DI Box

The Radial JDI is a passive direct box designed to handle extreme signal levels without distortion of any kind. Unlike an active DI that is limited by the buffering amplifier’s rail voltage, the JDI employs a Jensen audio transformer as the engine. Jensen transformers are legendary in their ability to gracefully handle transients while delivering a smooth, warm sounding Bessel curve, reminiscent of the finest vintage gear. Ruler flat from 10Hz to 40kHz and with virtually zero phase deviation, the JDI delivers the natural, pure sound of the instrument without artifact.

The 100% passive circuitry inside the JDI is incredibly efficient. The transformer performs both high-to-low impedance conversion and signal balancing at the same time with minimal loading and does so without any power whatsoever. The transformer also introduces a magnetic bridge that passes signal while rejecting stray DC voltage. This makes the JDI particularly adept at eliminating hum and buzz caused by ground loops.

Features include input and throughput ?” connectors, -15dB input pad, ground lift, and 180? degree polarity reverse to help phase align the instrument with the PA. A secondary circuit is added for direct interfacing with high output devices such as guitar or bass amp loudspeakers plus a unique merge function allows stereo sources such as keyboards to be summed mono, saving valuable input channels.

Built tough to handle the abuse of live touring, the JDI features a 14-gauge steel I-beam inner frame and a unique book-end outer shell. The innovative design eliminates stress on the PCB, reducing opportunity for solder joints to go ‘cold’ while the outer shell creates a protective zone around the switches and connectors. The steel casing resists noise-causing electromagnetic pollution and the transformer’s sensitive inner workings are further protected from magnetic fields with a MuMETAL® can. This ensures the signal transfer is quiet and free from hum. These combined features have made the Radial JDI the most popular passive direct box in professional touring and an excellent choice for instrument interface in the studio!

The Radial JDI… the world\'s finest passive direct box.

• Compact, high-performance passive direct box
• Jack input 1/4" TS in and parallel out
• Gold-plated XLR output / impedance balanced
• Super-flat frequency output for uncolored sound
• Switchable filter that optimizes the DI for guitars
• Instrument/Amp switch lowers the input level 30dB for feeding amplifiers into the DI
• Instruments or amplifier outputs with up to 3,000 watts can be connected directly
• Offers impedance and signal matching of instruments to mixers
• Perfect for stage and studio use
• Ground lift switch eliminates typical ground loop problems
• Rugged metal case can take the rigors of the road

• Type: Passive DI Box
• Channels: 1
• Ground Lift: Yes
• Inputs: 1 x 1/4"
• Outputs: 1 x 1/4“, 1 x XLR
• Height: 1.4"
• Width: 3.75"
• Depth: 5"
• Weight: 0.66 lbs.
• Manufacturer Part Number: DI600P

The Stewart ADB-1 is a single channel active direct box that allows an unbalanced source to
directly feed a balanced input. Musical instruments, tape recorders, VCRs and sound projectors
can be run "direct" to the mixing console, avoiding unnecessary degradation of sound quality.
The ADB-1 operates on either phantom power or a 9-volt battery.

FEATURES:
Flat response
Low distortion
Low noise
Wide dynamic range
No transformer
RF protection on input and output
Switchable ground isolation
Flush mounted slide switches

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
 

Phantom or battery powered in a rugged steel chassis, with separate Speaker Level input connector
 
The ARX DI-PLUS represents another major step forward in active direct boxes. Packaged in
a single channel stand-alone format, the DI-PLUS represents a fresh look at active D.I. concepts.
Precision engineered
Ultra quiet, ultra clean circuitry delivers maximum headroom whatever the signal. Premium grade
components, plus an all-steel chassis gives excellent hum and noise specifications and superb
audio quality in a tough, roadworthy package.
Level control
The DI-PLUS features a Normal gain high impedance unbalanced input on the front panel, running to
a balanced XLR output on the rear. There is also a separate -40dB Speaker Level input for signal coming
from the External (auxiliary) speaker output of an amplifier. A a global Pad switch drops both the normal
input and the speaker input by a further 20dB, making it suitable for all applications, from the softest
keyboard to the hottest broadcast levels.
 
Battery compartment
The revolutionary simple 'clamshell' action of the DI-PLUS battery compartment makes battery changing
extremely easy, even on the darkest stages.
A 9v alkaline battery snaps into a PCB mounted battery holder for fast, secure location. No fragile battery
clip leads to break, no tools required, no screws to lose. Production crew heaven!
 
Automatic Phantom switching
The DI-PLUS will automatically switch itself to the console's own Phantom Power, if available, and an LED
will indicate this mode. Turn the Phantom Power off and it will instantly revert back to battery mode.
Rugged all-steel case
A lot of direct boxes are fitted into brittle cast alloy cases. Not this one! The tough all-steel inner and outer
chassis of the DI-PLUS provide excellent RF/EMF shielding while making it a sturdy, heavy duty unit that is
hard to dislodge, and hard to leave behind.
 
Rear panel showing XLR connector, ground lift switch, and captive screw for opening up the unit
for battery changing
 
Whether you're a Studio or Live Sound engineer, installation contractor, or broadcast engineer, you want all
the dynamics and clarity of the original sound source transferred to the mixing console. The ARX DI-PLUS
provides a rugged, no-compromise solution to all direct injection and signal balancing requirements.
 
T E C H N I C A L  S P E C I F I C A T I O N S:
Max Input Level
+13 dB Phantom powered
+6 dB Battery powered
Input Impedance 1 Meg Ohm
Max Output Level
+17 dB 10K Ohm load Phantom powered
+12 dB 10K Ohm load Battery powered
+11 dB 600 Ohm load Phantom powered
+12 dB 600 Ohm load Battery powered
Output Impedance 680 Ohms Balanced
Output Signal to Noise
-100 dB unweighted
-104 dB A weighted
Dynamic Range
117 dB 10K Ohm load Phantom powered
112 dB 10K Ohm load Battery powered
111 dB 600 Ohm load Phantom powered
107.5 dB 600 Ohm load Battery powered
Distortion
100 Hz .0027%, 1KHz .0028%, 10KHz .0037%
Frequency Response 20Hz to 20KHz, ± 0.2 dB
Gain through Unit: 6dB (Normal input, Pad switch out)
Pad Switch: -20 dB attenuation
Speaker Input
-40 dB attenuation, equivalent to 100:1 decrease in input level
-60 dB attenuation available with Pad switch
Input Connectors
Insulated jacks (!!!Note that the Input connector switches the unit on
when a plug is inserted. Remove plug when storing to avoid battery drain!!!)
Output Connector
3 pin XLR. Wired Pin 1 Ground, Pin 2 + Hot, Pin 3 - Cold.
With Audio Ground (Pin 1) lift switch
Construction
All-steel chassis, fibreglass PCB
Battery Access
Twist connector opens chassis, snap-in battery holder inside.
No tools required
 

The alphaton Direct Injection-Box SM-50 allows direct connection of electric guitars,
electric bass, and electronic music instruments with mixing desks of PA systems
and of recording studios.
The SM-50 reduces the amount of microphones used on stage, thus improving gain
before feedback.
Coloration of sound is avoided. Clean signal without interference from other instruments
eases the job of the recording engineer. The use of a strong aluminium die-cast box allows
trouble-free function for a number of years even under adverse conditions. Double grounding
(hum) can be eliminated by activating the built-in ground-lift switch. Isolation voltage between
input and output is 2500 volts, against ground 1500 volts (with ground-lift switch activated).
The box thus complies with toughest safety standards.

Technical Data

input impedance 20 kOhm
input impedance, instrument input impedance, line-In input impedance, speaker output impedance 200 Ohm
frequency response 30 ... 20000 Hz, ± 1 dB
THD isolation voltage tranformer pri/sec 2500 V
                        outpur to ground 1500 V
inputs 1/4" phone jacks, unbalanced
outputs XLR, balanced, microphone level.
           pin 1 = ground, pin 2 = hot, pin 3 = cold
case aluminium die-cast
weight 230 g
dimensions113 x 71 x 37 mm