Pioneer SPEC-2 Service Manual

STEREO POWER
AMPLIFIER
SPEGI?,
KCU
(DrrroNEER'

Pioneer SPEC-2 Specifications

General

Power Output	250 watts per channel into 8Ω (stereo)
Frequency Response	5 Hz to 100 kHz
Input Sensitivity	1.5 V
Signal to Noise Ratio	110 dB
Type	Stereo Power Amplifier

Summary

Specifications

Power Amplifier Specifications

Details amplifier circuitry, output, distortion, frequency response, damping, and noise.

Front Panel Facilities

Protection Indicator

Circuit Description

Power Amplifier Circuitry

Describes the cascaded differential, triple push-pull OCL amplifier circuit.

Current Limiter Circuit

Peak Level Meter Circuit

Protection Circuit Overview

Explains the circuit's purpose to protect equipment and indicate malfunctions.

DC Balance Detector Circuit

Surge Current Suppressor Circuits

Details primary and secondary surge suppression for the power transformer.

Block Diagram

Adjusting Procedures

Idle Current Adjustment

Step-by-step guide to set the idle current to 30mV.

Current Limiter Sensitivity Adjustment

Guide to adjust VR2 and VR3 for optimal current limiting.

Meter Amplifier Adjustment

Steps to calibrate the meter amplifier for 0dB indication.

Disassembly Instructions

Parts Locations

Top View Component Identification

Front Panel Component Identification

Rear Panel Connections

Schematic Diagrams and Parts Lists

Schematic Diagram and Miscellaneous Parts

Lists capacitors, fuses, resistors, potentiometers, switches, semiconductors, and other parts.

Power Amplifier Schematic

Detailed schematic for the power amplifier stages.

Power Supply Circuit Assembly (AWR-093)

Power Supply Circuit Parts List (AWR-093)

Lists all components for the power supply circuit assembly.

Power Amplifier Assembly (AWH-045)

Power Amplifier Assembly Parts List (AWH-045)

Meter Amplifier Assembly (AWM-081)

Meter Amplifier Assembly Parts List (AWM-081)