S F S - 8 0
STER EO TU BE AM PLIFIER
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!
VAC UU M TU B ES
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.
Need help?
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