Ampeg Guitar Amplifier SJ12T user manual

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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Table of Contents:
The Front Panel  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4,5
The Rear Panel  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Important Information About Tubes and Tube Products
A Brief History Of The Tube  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Tube Types And Usage  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7,8
The Nature Of Tubes: Why (And When) To Replace Them ....

3
IMPORTANT SAFETY INSTRUCTIONS•READ, FOLLOW, HEED, AND KEEP ALL INSTRUCTIONS AND WARNINGS.
•DO NOT OPERATE NEAR ANY HEAT SOURCE AND DO NOT BLOCK ANY VENTILATION OPENINGS ON THIS APPARATUS. FOR
PROPER OPERATION, THIS UNIT REQUIRES 3” (75mm) OF WELL VENTILATED SPACE AROUND HEATSINKS AND OTHER AIR
FLOW PROVISIONS IN THE CABINET.
•DO NOT USE THIS APPARATUS NEAR SPLASHING, FALLING, SPRAYING, OR STANDING LIQUIDS.
•CLEAN ONLY WITH LINT-FREE DAMP CLOTH AND DO NOT USE CLEANING AGENTS.
•ONLY CONNECT POWER CORD TO...

4
1. Guitar Input accepts the output from
your instrument by means of a shielded
signal cable. This input signal to this jack
is not attenuated and accommodates
instruments with standard output signals.
If your instrument has a strong output
signal, use the Accordion Input (#2).
2. Accordion Inputaccepts the output
from your instrument by means of a
shielded signal cable. The signal to this
jack is attenuated 6dB to accommodate
instruments with stronger output signals.
3. Volumecontrols the overall...

5
6. Tremolo-Intensity sets the depth of
the tremolo effect. For slow, smoother
vibrato effects try the Intensity control at
around 6 and the Speed control at 1. For
the really wild sounds, crank the
Intensity up towards 8 (or beyond) and
go from there.
7. Reverb-Dimension controls the
amount of reverberation applied to the
signal. With the control at the “0” position
there is no reverb applied; as the control
is turned towards “10” the amount of
reverb increases accordingly.8. Power lightilluminates...

6

(Reverb cables:
do not disturb)
(Reverb cables:
do not disturb)1314151011
12
10. Power cord connects the amplifier
to
 a  suitable  source of A.C.  voltage. This
is
 a  grounded, three-wire cord and must
be
  connected to a properly grounded
outlet.
DO NOT attempt to defeat the
ground
  connection of  the power cord!
If
  your amp was purchased outside  of
the
  United States, see the sticker next to
the
  A.C.  connector  for its power ratings.
Follow
  the above guidelines. 
1 1,12. Power T ubes:...

7
Important Information About Tubes and Tube Products:
ABrief History Of The Tube:
In 1883, Edison discovered that electrons would flow from a suspended filament when enclosed in an evac-
uated lamp. Years later, in 1905, Fleming expanded on Edisons discovery and created the Fleming Valve.
Then, in 1907, Dr. Lee de Forest added a third component – the grid – to the Flemings Valve and the vac-
uum tube was a fact of life. The door to electronic amplification was now open.
During World War II, data gleaned...

8
Important Information About Tubes and Tube Products (Continued):
low-end response and produces more harmonics at mid and high frequencies (creamier sound). These
differences become more noticeable at higher volumes.
The 6L6 tubes produce a big low-end thump and have a very good dynamic range. They offer a more tradi-
tional American Rock sound. The 6V6 tubes produce a creamy sound with nice distortion. On the other
hand, the KT88 produces a big low-end but sounds more like an EL34 in the mid and high...

9
Important Information About Tubes and Tube Products (Continued):
You can check your preamplifier tubes for microphonics by turning the amplifier on, turning up the gain and
tapping lightly on each tube with the end of a pencil or a chop stick (my favorite). You will be able to hear
the tapping through your speakers, which is normal. It is not normal for a tube to ring like a bell after it’s
tapped. If it does ring then it’s microphonic and should be replaced. Remember to use only high quality, low...

10
Important Information About Tubes and Tube Products (Continued):
Survival Tips For Tube Amplifiers:
To prolong tube life, observe these tips and recommendations:
• Match the impedance of your speaker cabinet(s) to your amplifier. Improper impedance matching will con-
tribute to early tube degradation and may cause premature tube failure.
• Make sure the speaker(s) are properly connected prior to turning on the amplifier.
• After playing the amplifier, allow sufficient time for it to properly cool down...