DB-2PX | Jensen Transformers

DB-2PX Two channel direct box

The Iso•Max DB-2PX is a stereo direct box designed to drive unbalanced instrument signals distances to 100 meters (300’) or more without high frequency loss or introducing noise into the signal path.

Converts unbalanced instrument signals to balanced

Eliminates hum and buzz caused by ground loops

Ruler flat frequency response from 10 Hz to 100 kHz

Plug and play easy to use, no power required

The design begins with a flanged steel enclosure for easy mounting in a rack or under a desk. This comes standard with ¼” inputs and XLR outs along with a removable screw-down barrier strip for installers. Inside, two high-performance Jensen JT-DB-EPC transformers provide galvanic isolation as they passively lower the impedance and perform the balancing. A high 140 kΩ input impedance reduces loading, enabling low-output instruments such as a vintage Fender® bass to be connected without losing tone. As hi-Z instruments are particularly sensitive to noise, internal Faraday shielding protects against pollution from RF. An external MuMETAL® can further protects the sensitive internal workings to ensure a quiet interference-free performance even when surrounded by magnetic fields from amplifiers, power supplies and stage light dimmers.

With over +22 dB of signal handling capacity, the DB-2PX gracefully handles extreme signals such as those produced by digital pianos while producing a warm Bessel response that is often referred to as ‘vintage’ sounding. These features combine to make the DB-2PX the ideal choice for studio or live use.

Applications

Passive Direct box with PA

Connect the hi-Z output from your keyboard to the DB-2PX and it will lower the impedance and balance the signal for long cable runs. It also eliminates hum and buzz caused by ground loops.

Laptop DI to PA system

Send the stereo output from your laptop, CD player or DJ mixer to the DB-2PX and it will deliver a balanced mic level output to feed a mic splitter or the mic input of your mixing console without noise or distortion.

DB-2PX in the studio

The high input impedance, exceptional signal handling and broad frequency response make the DB-2PX a great choice for interfacing electric bass or acoustic guitar to the PA or recording system.

Specifications

All levels are input unless noted

PARAMETER	CONDITIONS	MINIMUM	TYPICAL	MAXIMUM
Input impedance, Zi	1 kHz, 0 dBu, test circuit 1	92 kΩ	97 kΩ	102 kΩ
Voltage gain	1 kHz, 0 dBu, test circuit 1	-40.0 dB	-38.6 dB
Magnitude response, ref 1 kHz	20 Hz, +4 dBu, test circuit 1	-0.25 dB	-0.08 dB	0.0 dB
Magnitude response, ref 1 kHz	20 kHz, +4 dBu, test circuit 1	-0.25 dB	-0.07 dB	+0.1 dB
Deviation from linear phase (DLP)	20 Hz to 20 kHz, +4 dBu, test circuit 1		+1.2/-0°	±2.0°
Distortion (THD)	1 kHz, +4 dBu, test circuit 1		<0.001%
Distortion (THD)	20 Hz, +4 dBu, test circuit 1		0.036%	0.10%
Maximum 20 Hz input level	1% THD, test circuit 1	+19.5 dBu	+21.5 dBu
Input common mode rejection ratio (CMRR) unbalanced source	60 Hz, test circuit 2		80 dB
Input common mode rejection ratio (CMRR) unbalanced source	3 kHz, test circuit 2	40 dB	45 dB
Output impedance, Zo	1 kHz, test circuit 1	145 Ω	150 Ω	155 Ω
Optimal cable length	input		3 m (10’)	15 m (50’)
Optimal cable length	output		30 m (100’)	150 m (500’)
Temperature range	operation or storage	0°C		70°C
Breakdown voltage*	primary or secondary to shield and case, 60 Hz, 1 minute test duration	250 V RMS

Graphs

Phase Distortion (DLP)

Frequency Response

THD vs Level at Low Frequencies

THD vs Frequency at Various Levels

DB-2PX Two channel direct box

The Iso•Max DB-2PX is a stereo direct box designed to drive unbalanced instrument signals distances to 100 meters (300’) or more without high frequency loss or introducing noise into the signal path.