control turned up).
Step 4
– Turn the vibrato channel tone control fully clockwise.
Step 5
– Turn the vibrato channel volume control clockwise and listen for a low level hiss from
the speaker. There may be a slight hum too, but any dramatic hum indicates wiring troubles.
Step 6
– If the above hiss is heard correctly, turn the vibrato channel volume control back to
minimum (leave tone control turned up).
Step 7
– With a 1/4” guitar cord, connect a suitable signal source (a guitar is good) into one of
the normal channel jacks.
Step 8
– Turn up the normal channel volume control on the amp and verify that the signal
from the signal source is coming from the speaker.
Step 9
– Repeat the above for the vibrato channel.
Step 10
– Turn the vibrato intensity control to “on” and verify that the vibrato is working.
Step 11
– Turn the vibrato speed control clockwise to verify that the speed is adjustable.
Step 12
– If everything checks good, we are almost done!
Final notes (important stuff I forgot to mention):
- If the amp squeals (becomes unstable) when played at high volumes, I recommend using a
wooden stick (old chop stick works great) and move the wires around. These would be the
wires between the turret board, the tube sockets, and the controls. Because the amp has a
great deal of gain, proper wire routing becomes important. Often a wire with a strong signal
will “bleed” into an adjacent wire causing troubles. This is easily corrected by moving the
physical location of the wires around. Turn the amp on as if you are going to play (the amp
must be connected to a cabinet), turn the controls fully up, and with your wooden probe, move
the wires in the amp around. Find the locations for these wires that are the quietest (for hum
and for potential feedback). You can use a dab of silicone sealant to hold the wires in place if
you like.
- If the amp “clicks” in rhythm with the tremolo speed, then I recommend moving the wires
around similar to the above technique. The tremolo oscillator signal is very strong and will
bleed into neighboring audio wires if the wires are too close.
A signal source can be a guitar or high impedance microphone or even a low level CD or
MP3 player. Using a speaker output from another amp is not recommended.
NOTE
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