EQ901B Series User Guide

Introduction

1. Features

2. What’s Included

3. Typical Installation Examples

3.1 Tape Monitor Loop Setup

3.2 Preamp Power Amplifier Setup

3.3 Connecting a Power Subwoofer

3.4 Typical Setup I/O

3.5 AC Power Connection

4. Setting Input Levels

5. Accessing the Input Level Switches

6. Using the Dual Output EQ Curves

7. Specifications

8. Warranty Terms

9. Contact Deer Creek Audio

Introduction

The Deer Creek Audio EQ901B Series is a direct replacement for existing BOSE 901 equalizers. The EQ901B features dual output equalization (EQ) curves, Normal and Enhanced, either of which will accommodate your 901 Series and can be selected based on personal preference. See below for instructions on using this feature.


The EQ901B installs in your tape monitor loop, pre-out/pre-in loop or between your preamp and power amp. Switchable input levels between 0.9 Vrms and 2.0 Vrms accommodate use with most preamplifiers, amplifiers or receivers. The EQ901B series is based on the miniDSP 2x4 digital signal processor.

1. Features

Precision engineered 901 Series model-specific EQ curves

Dual output EQ curves Normal and Enhanced

Simple drop-in replacement

High fidelity and low noise

2. What’s Included

EQ901B Equalizer

Frequency equalization curves for your 901 Series

Regulated power supply

3. Typical Installation Examples

Analog audio input and output connections are made directly to the RCA input and output jacks. When making these connections, make sure to power off the equipment being connected.

3.1 Tape Monitor Loop Setup

Figure 3.1

3.2 Preamp Power Amplifier Setup

The two unused outputs connect to your subwoofer L and R line inputs. The subwoofer controls can then be adjusted to your preference.


Figure 3.2

3.3 Connecting a Power Subwoofer

 

Figure 3.3

3.4 Typical Setup I/O

Figure 3.4

3.5 AC Power Connection

The EQ901B does not have a power switch and can be left powered on, as power consumption is very low. You also may power your EQ901B from a switched outlet on your receiver.

4. Setting Input Levels

The analog audio input levels are switchable between 0.9 Vrms and 2.0 Vrms to accommodate use with most preamplifiers, amplifiers or receivers. If you are experiencing excessive signal level or distortion, you may need to switch the unit to the 2.0 Vrms setting.


The EQ901B model is shipped with the input levels preset to 0.9 Vrms.

 

Figure 4.1


0.9 Vrms position. With this setting, the maximum input signal voltage allowed before clipping the A/D convertor is 0.9 Vrms. This position is typically used when the EQ901B is connected between a preamp and a power amplifier.


2.0 Vrms position. With this setting, the maximum input signal voltage allowed before clipping the A/D convertor is 2.0 Vrms. This position is typically used when the EQ901B is connected in a tape recording loop (REC/in to PB/out).

5. Accessing the Input Level Switches


Figure 5.1

6. Using the Dual Output EQ Curves

The EQ901B is equipped with two equalizer (EQ) curves. The Normal EQ curve is available on outputs 1 and 2, and the Enhanced EQ curve is on outputs 3 and 4.


If you're using an amplifier or receiver with two tape monitor loops, you can connect the EQ901B outputs 1 and 2 to tape playback inputs 1, and outputs 3 and 4 to tape playback inputs 2. Then you will be able to switch easily between the two equalizer curves. If your configuration is a pre-amplifier out / main amplifier in setup, you'll need to manually move the cables from outputs 1 and 2 to outputs 3 and 4. Be sure to power off all equipment before making these adjustments.

 

 

Figure 6.1

7. Specifications

Distortion:  < 1% THD at maximum input

Maximum input voltage:  2.0 Vrms or 0.9 Vrms - jumper settable

Dynamic range:  un-weighted > 98dB

Analog Devices:  ADAU1701 Digital Signal Processor Engine

Dimensions:  26 h x 107 w x 94 d mm

8. 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. Return shipping is the responsibility of the customer.

9. Contact Deer Creek Audio

Please contact us with any questions or comments:


staff@deercreekaudio.com

720.726.9272