EQ901USB-I/II User Guide


The EQ901USB-I/II is an upgrade replacement for existing BOSE 901 Series I/II Equalizers.  It includes Series I/II specific EQ curves, analog and digital audio inputs.  The EQ901USB-I/II is also a high performance digital pre-amplifier (DAC) intended to drive high quality power amplifiers or integrated amplifiers/receivers

The EQ901USP-PS Overview

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

Precise 901 Series I/II equalization performed digitally before the DAC in an Analog Devices 400 MHz SHARC DSP processor with 24 bit resolution

Remote selectable inputs:

1.    Analog


3.    USB

Remote selectable tonal characteristics settings:

1.    Normal mode

2.    Warm mode

3.    Bright mode

4.    Rock mode

Remote volume control with 0.5 dB resolution and mute

Ultra low distortion 2 Vrms output driver stage

What’s Included

EQ901USB equalizer for your BOSE 901 Series I/II

Four precision engineered tone adjustment equalization curve

 IR Remote Control

USB Cable

Typical Connections

Loading your USB drivers

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

The driver for the miniDSP 2x4 HD enables the plugin to communicate with it.  In addition, it allows USB streaming from the computer to the 2x4 HD and installs the control panel for this purpose.  To install the driver, the EQ901USB-II 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_v4.11.0_2017-06-19_setup   (for windows 10)


Hardware Installation

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

Level Setting

Your EQ901USB-I/II is being delivered with an internal level (gain) setting of -50db, which you will adjust with the supplied remote control.   It has been set low to begin with to protect your system at turn on.  Once you have your inputs connected you can adjust all the gain levels for optimal mid control performance.

USB Music Server Volume Setting

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

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

2.    Warm

3.    Bright

4.    Rock

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

1.    Analog


3.    USB

IR Remote Control Functions



Selecting Tonal Characteristics Modes

Selection of the tone mode is generally a subjective choice based on what sounds best to you.  Technically, Normal mode is the most neutral, Warm mode provides a bit less treble with more bass, Bright mode adds a bit more treble and bass reduction, and Rock mode is intended for high level listening.  As an example, rooms with heavy curtains, rugs, and soft furniture may sound better with the Bright mode.


·    EQ901USB-II platform base: miniDSP 2x4 HD

·    Digital Signal Processor Engine: Analog Devices Fixed point DSP SHARC ADSP21489

·    USB controller: XMOS Xcore200

·    Digital to Analog Converter (DAC): AK4626A

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

·    Audio Input Connectivity:

o   RCA, TOSLINK (optical), USB Audio

·    Audio Output Connectivity

o   Unbalanced output, RCA

·    Input / Output Max Levels:

o   IN: 2Vrms / 4Vrms (jumper-selectable)

o   OUT: 2Vrms

·    Input Impedance: 10 k Ω

·    Output Impedance: 560 Ω

·    Filtering Technology: FIR + IIR

·    Dimensions: 27 x 119 x 107 mm

·    Power: 12 VDC single supply, 2.1 mm round plug, 2.5Watt

·    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-II 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