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DB4A      4 Channel Rack Mount Direct Box



  • Floating Transformer-Balanced XLR Output for Maximum Isolation
  • 4 Independent Channels for 4 Keyboards, Drum Machine Outputs, etc.
  • 3 IN/OUT Jacks per Channel for Convenient Loop-Thru
  • LINT Mode Handles Signals to +34 dBv
  • GND/LIFT Switch Eliminates Hum and Buzz
  • Rack-mounted “Uni-box” Construction for Superior Protection and Shielding
  • Flush-mounted Switches and Connectors Resist Damage
  • Passive Design Requires No Batteries or Phantom Power



The DB4A provides four discrete “direct-box” channels in a convenient single space (1 3/4” , 44.45mm) rack-mounting package. Ideal for the multi-keyboardist, it is equally well suited to any application requiring the interface of unbalanced high-impedance equipment and balanced low-impedance mixer inputs.

Unlike the traditional “mic on the speaker” approach, the direct approach delivers the clarity and punch that a modern sound demands. The full richness and character of the instruments is preserved because the distortion and coloration of speakers and microphones has been eliminated.

The versatile design of the DB4A allows easy integration with any high-quality audio system. Three parallel-connected IN/OUT jacks for unbalanced signals make “patching in” at virtually any stage of the signal path a simple task. Signals may be taken straight from the instruments (and effects devices) themselves, or from sub-mixer outputs (if you have to run out of mixer channels). Of course, multiple DB4A’s can be used when separate outputs from each instrument or effect are needed.

The DB4A’s rugged 16–gauge steel and aluminum “Uni–box” construction enclosure is finished in a durable black texture powder coat finish with black anodized aluminum side channels. Easy– to–read control graphics are incorporated into the Lexan® front and back panel overlays. Inside, DBT-P transformers combine superb audio quality with unsurpassed noise rejection. The DB4A can be mounted in any standard 19” (482.6mm) rack.



All measurements made with 0Ω source feeding IN/OUT and 1.0 kΩ load on all LO-Z OUTPUT to simulate typical "real world" instrument pick-up and mic preamp. 0 dBv ref. = .775 volts.

Frequency Repsonse:
20 Hz - 20 kHz, ± .5% @ -15 dBv output.
-3 dB @ approximately 85 kHz.

Total Harmonic Distortion:
<.03% 20 Hz - 20 kHz @ -30 dBv output.
<.1% 30 Hz - 20 kHz @ -15 dBv output.
<.25% 20 Hz - 20 kHz @ -15 dBv output.

Phase Response:
<-18 degrees @ 20 kHz (ref. 1.0 kHz).

Rise Time:
<4.5 microseconds (2.0 kHz square wave, 10%-90%).

Voltage Stepdown:
<22 dB @ 1.0 kHz (INST mode).
SPKR mode attenuate signal by 20 dB

Input Impedance:
>130 kΩ @ 1.0 kHz (INST mode).
>105 kΩ @ 10kHz (INST mode).
Nominal source impedance is 20 kΩ.
Approx. 8.2 kΩ (SPKR mode)
Nominal source impedance is 0 Ω.

Output Impedance:
<210 Ω @ 1.0 KHZ.
<215 Ω @ 10 kHz.
Nominal output impedance is 1.0 kΩ.

Maximum Input Level @ 50 HZ for 1% THD:
+16 dBv (INST), +34 dBv (LINE) @ 20 Hz. 
+21 dBv (INST), +41 dBv (LINE) @ 30 Hz. 
+26 dBv (INST), +46 dBv (LINE) @ 50 Hz.