HHB Circle 5A User Manual

Version 1d: 01.99
Page
Service manual
HHB Circle 5A
Powered
Monitor speaker
Manual: Version 1d 01.1999
This manual is subject to change without notice.
Always check with HHB that you are using the latest version.
Also available as an Adobe Acrobat V3 file.
When printing this file, for clear sharp pictures on a black & while laser, it may be necessary
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WARNING! DANGER OF ELECTRICAL SHOCK
Opening mains operated equipment like the HHB Circle5A incurs a risk of electric
shock.
DO NOT attempt to open this equipment unless you are qualified to do so, have the neces-
sary test equipment and are operating the Circle 5a from an ISOLATED POWER SUPPLY.
Ensure that only the correct mains voltage is applied, as marked on the module.
NEVER OPERATE OR OPEN THIS SPEAKER IN DAMP OR WET CONDITIONS AND
NEVER ALLOW IT TO BE USED OUTSIDE.
ENSURE THAT ALL POWER AND SIGNAL CABLES ARE IN PERFECT CONDITION AND
ARE CORRECTLY FUSED.
IF IN DOUBT, CONTACT HHB IMMEDIATELY BEFORE PROCEEDING.

HHB Circle 5A Specifications

General

Brand	HHB
Model	Circle 5A
Category	Speakers
Language	English

Summary

HHB Circle 5A Service Manual Introduction

Electrical Safety Warning

Crucial safety warning regarding the danger of electrical shock when opening the unit.

1.0 External Controls and Connectivity

Input Connector Details

Description of balanced XLR and unbalanced Phono input connectors and their pin configurations.

Master Volume Control Function

Explanation of how the Master Volume control scales input signals to drive the power amplifiers.

Removing the Circle 5a Active Module

Tools Required for Module Removal

Lists the specific screwdrivers needed for safely removing the active module.

Module Screw Removal Steps

Detailed instructions for unscrewing the module from the cabinet, noting screw types.

2.0 General Circuit Arrangement

Mute Relay Operation

Explanation of the mute relay's role in preventing speaker thumps during power cycling.

Power On LED Indicator

Description of the power-on LED and its indication of transformer and PSU function.

Mute Relay Modification Details

Resistor Change for Mute Relay Threshold

Details the modification involving changing resistor R46 to adjust the mute relay's switch on/off threshold.

Amplifier Module Level Adjustments

Tweeter Level Reduction

Guidance on reducing the tweeter level by adjusting a preset, with specific dB reduction levels.

Bass Level Adjustment Warning

Cautionary note against adjusting the bass level adjuster as it is factory calibrated.

Connections to the Circuit Board

Circuit Board Wiring Diagram

Diagram illustrating the connections between various components and the main circuit board.

HHB Circle 5 Power Amplifier Parts List

Component Values and Types

Detailed list of resistors, capacitors, diodes, transistors, and ICs with their values and types.

Mechanical Parts List

Physical Component Specifications

List of mechanical parts including heatsinks, connectors, screws, and chassis elements.