EQ901USB User Guide



The EQ901USB  is an upgrade replacement for existing BOSE 901 Equalizers.  The EQ901USB Series features four specifically designed equalization curve sets unique to each Series I/II, III/IV or V/VI (select your series when ordering).

The EQ901USB is also a high performance digital pre-amplifier (DAC) intended to drive high quality power amplifiers or integrated amplifiers/receivers.  Analog, USB and TOSLINK digital audio inputs are provided.

When used in the digital input mode the music stream is maintained in the digital domain all the way through the 901 equalization process.  This is the purest and highest fidelity way to drive your 901’s.

The EQ901USB Overview

  • USB/TOSLINK Streaming Digital to Analog Converter (DAC) with built in equalization curves for the 901 Series V/VI

  • Precise BOSE 901 equalization is performed digitally before the DAC in an Analog Device 400 MHz SHARC DSP processor with 24 bit resolution

  • The four BOSE 901 tone modes (EQ curves) are available on all four outputs. Two identical stereo pairs outputs are available allowing for dual active stereo systems (two stereo power amps) or the addition of an active subwoofer(s)

  • Remote selectable inputs:

  1. Analog


  3. USB

  • Remote selectable tonal characteristics settings:

  1. Normal mode

  2. Enhanced mode

  3. Warm mode

  4. Low frequency reduction mode

  • Remote volume control with 0.5 dB resolution and mute

  • Ultra low distortion 2 Vrms output driver stage

  • Selectable input sensitivity of 2 Vrms or 4 Vrms

 What’s Included

  • EQ901USB equalizer for your BOSE 901 Series I/II, III/IV or V/VI (select your series when ordering)

  • Four precision engineered tone adjustment equalization curves

  • Two identical stereo pairs outputs are available allowing for dual active stereo systems (two stereo power amps) or the addition of an active subwoofer(s)

  • Deer Creek Audio USB drive with PC USB audio driver 

  • IR Remote Control

  • USB Cable

  • US Regulated power supply - see option for global supply

Typical Connections

Stereo Mode

Dual Stereo (Quad) Mode

Active Subwoofer Mode

Tape/Processor Loop Set Up

Loading your USB drivers (PC only)

Prior to installing the USB drivers, be sure the following programs are up to date:

  • Microsoft .NET framework (version 3.5 or later)

  • Latest version of Adobe Flash

  • Latest version of Adobe Air 

If you haven’t updated these recently, you should download and install the latest versions prior to running the USB drivers.

Driver installation (PC only, Apple is plug and play)

The driver for the miniDSP 2x4 HD enables USB streaming from the computer to the EQ901USB.  To install the driver, the EQ901USB must be connected to the computer with a USB cable and powered on with the supplied AC adapter.  Then select and load the appropriate driver for your PC version from the enclosed CD.


  • miniDSP_UAC2_v4.47.0_ForWin7_8_10.exe (for windows 10)

Hardware Installation

When audio input and output connections are being made, be sure that all associated equipment is powered off.  Also, when you power the EQ901USB on and off, be sure that the associated equipment is off. Connect power to the EQ901USB before turning associated equipment on.

Level Setting

Your EQ901USB is being delivered with an internal level (gain) setting of 0db (max, no insertion loss), which you will adjust with the supplied remote control.   It has been set with the analog Inputs selected. Be sure to turn down your music source to protect your system at turn on. Once you have your inputs connected and all components on, you can adjust all the gain levels for optimal volume mid-position control performance.

Subwoofer Settings

To begin, your subwoofer should be set at mid level gain, and the crossovers should be set at the mid level setting.  After you have the system up and running adjust the subwoofer level, phase, and crossover to get the best response.

USB Music Server Volume Setting Warning

If you are streaming digital music via a server such as foobar2000, JRiver, Roon, etc., begin with the server application level set low .

Remote Control Functions

The supplied IR remote control has the following functions and is the only user control interface.

Tone configurations selected on the remote control:

  1. Normal mode

  2. Enhanced mode

  3. Warm mode

  4. Low frequency reduction mode


The input source is selected by scrolling on the remote control source button:


1.    Analog


3.    USB


Selecting Tonal Characteristics Modes

Selection of the tone mode is generally a subjective choice based on what sounds best to you.  Specifically: Normal mode is the most neutral, Enhanced mode provides a richer sound with more treble and bass, Warm mode adds midrange with slight treble reduction, and Low frequency reduction mode is intended to control bass in smaller rooms or on boomy recordings .



  • EQ901USB platform base: miniDSP 2x4 HD

  • Digital Signal Processor Engine: Analog Devices Fixed point DSP SHARC ADSP-21489

  • USB controller: XMOS xCORE-200

  • Digital to Analog Converter (DAC): AK4626A

  • Internal Processing resolution & Sample rate: 32 bit / up to 192 kHz

  • Audio Input Connectivity:  RCA, TOSLINK (optical), USB Audio

  • Audio Output Connectivity:  Unbalanced output, RCA

  • Input / Output Max Levels: In 2 Vrms / 4 Vrms (jumper-selectable), Out 2 Vrms

  • Input Impedance: 10 k Ω

  • Output Impedance: 560 Ω

  • Filtering Technology: FIR + I/IIR

  • Dimensions: 27 x 119 x 107 mm

  • Power: 12V DC single supply, 2.1 mm round plug, 2.5 Watt

  • IR Remote: miniDSP Remote


Analog Input Level

The analog audio input levels are switchable between 2 and 4 Vrms to accommodate use with most equipment.  The EQ901USB is shipped with the analog input level set to 2 Vrms.


Warranty Terms

This product is warranted to be free from defects in materials and workmanship for a period of one year from the invoice date.  Warranty does not cover failure of the product due to incorrect connection or installation, improper or undocumented use, unauthorized servicing, modification or alteration of the unit in any way, or any usage outside of that recommended in this manual.  The customer provides return shipping to Deer Creek Audio. Deer Creek Audio is an Authorized miniDSP dealer.

Please contact us with any questions you may have