Sonic Frontiers SFS-80 - User Manual

S F S - 8 0
STEREO TUBE AMPLIFIER
O P E R A T I N G M A N U A L
We at Sonic Frontiers are sure that you will derive many years of listening pleasure with your new SFS-80 Stereo Tube
Amplifier. This brief operating manual contains important information regarding the operation and care of the ampli-
fier, so be sure to read this manual carefully and follow these simple instructions in order to keep it looking, operating
and sounding its best!
VACUUM TUBES
Handling
We suggest that you do not handle the large power tubes with your bare hands or fingers as skin oils deposited on
the glass surface can “leach” through the glass envelope and cause the tube to become “gassy.” In other words, your
tube life may be shortened unnecessarily. Use a paper towel or one of the cotton gloves (supplied) instead. This is
also the recommended procedure for handling the small input tubes. Also, check to be sure that none of the 6DJ8
tube pins are bent when you install them.
Installation
Whenever you remove or insert the input or power tubes into their sockets, handle them gently and do not force them
into the sockets. Instead, “rock” them slightly as you slowly push them into place, making sure that they are properly
seated.
Recommended Tube Types
Your SFS-80 amplifier is supplied from the factory with 6DJ8 tubes for the input and driver stages (installed into the
small sockets). You may also use tubes of the following designations: ECC88, 6922, or 7308/E88CC.
The power tubes are factory supplied matched pair KT99a’s but you may also use 6550/6550A or KT90/KT99 types.
EL34/6CA7 tubes may also be used but the available output power will be reduced by about 50% to 40 watts.
Although not essential, we recommend the use of matched pairs of power output tubes for lowest distortion.
Tube Biasing
This is a simple yet important function of the front panel meter, the selector switch and the four slotted adjustment con-
trols protruding above the top surface of the chassis.
It is essential that the following procedures be followed before you turn on your SFS-80 amplifier.

Summary

VACUUM TUBES

Handling Vacuum Tubes

Advice on handling vacuum tubes to prevent contamination and damage to pins.

Tube Installation

Instructions for gently inserting and removing vacuum tubes from their sockets.

Recommended Tube Types

Lists compatible tube types for input, driver, and power stages, and recommendations.

Tube Biasing Introduction

Introduces tube biasing as an important function involving front panel controls.

OPERATING PROCEDURES

Tube Biasing Procedure

Step-by-step instructions for setting the bias for the amplifier's output tubes using front panel controls.

Amplifier Cleaning

Guidance on cleaning the amplifier's chassis and transformer top covers using specific materials.

Troubleshooting Guide

A checklist to follow if the SFS-80 amplifier fails to work, covering common issues.

TROUBLESHOOTING AND OPERATION

Troubleshooting Checklist Details

Further steps in the troubleshooting guide, including checking fuses and power tubes for faults.

Operate;Mute Switch Function

Explains the purpose of the OPERATE/MUTE switch for muting the input signal during cable changes.

Tube Cage Purpose

Describes the function of the tube cage for protection and safety, and its installation difficulty.

OPERATIONAL GUIDELINES

Ventilation Requirements

Instructions on amplifier placement for proper airflow to prevent overheating and damage.

Packing Material Recommendation

Advises retaining original packing material for potential future shipping and notes liability for damage.

General Safety Precautions

Lists safety guidelines regarding water, heat, power sources, cleaning, servicing, and non-use periods.

LIMITED FIVE YEAR WARRANTY

Warranty Coverage and Limitations

Details the five-year warranty, exclusions, conditions, and the process for returns and repairs.

TECHNICAL SPECIFICATIONS

Amplifier Specifications

Lists technical details including power, frequency response, impedance, sensitivity, requirements, tubes, dimensions, and weight.

Sonic Frontiers SFS-80 Specifications

General

Signal-to-Noise Ratio	90dB
Input Impedance	100k ohms
Power Output (8 ohms)	80W
Power Output (4 ohms)	80W
Input Sensitivity	1V RMS