Hughes & Kettner Switchblade Head 100 Manual De Instrucciones página 22

Switchblade
Note: Replacing tubes for experimentation purposes is not
recommended. Installing the wrong tubes will damage the amp and
cost you a lot more than you bargained for in repair costs.
Before you start swapping tubes, ask yourself these questions:
• Was the fault or failure of the tube caused by the tube itself or by a
flawed peripheral device or component, perhaps a defective speaker
cable? If you don't get to the bottom of the problem and remedy it,
it may crop up again even after you replace the tubes.
• Did the Mains voltage fluctuate or spike while the amp was on? In
all-tube amps, over-voltage surges in the Mains net can certainly
cause drop-outs. Over-voltages are often caused by generators and
faulty high-current power circuits.
• Perhaps a fuse blew even though none of the tubes is actually
defective? An old fuse, tube de-ionization or Mains voltage power
surges may have triggered the fuse.
Things to Bear in Mind When Replacing Tubes
Replacing tubes is a job best left to qualified professionals!
Accordingly, the following guidelines are addressed and apply to
qualified service technicians only:
• Pull Switchblade's Mains plug and allow for a discharge time of at least
two minutes before removing the chassis from the rear of the amp.
• Once the chassis has been removed, carefully ease the tubes out of
their sockets.
• A single power tube may only be replaced if the replacement tube
precisely matches the original, that is, the old and new tubes'
characteristics are identical.
• When a new matched set of power tubes with characteristics
identical to the old set is installed, it is not absolutely necessary to
re-bias the amp.
• The amp must be biased when a replacements set's characteristics do
not match the original set's. This requires experience and extensive
working knowledge in measuring techniques, which is why this is a
job for qualified technicians with tube amp tuning experience.
How to Prolong Tube Life
• Never operate Switchblade without connecting a load (loudspeaker)!
• Never connect speaker cabinets with an impedance that is too high
or low!
• Always use high-quality, heavy-duty speaker cords that won't crimp!
• Use the
switch for short breaks!
STANDBY
• Avoid exposing the amp to vibrations, especially when it's powered up.
• Switch the amp off well before transporting it to allow tubes to cool
off completely.
• Make sure all peripheral devices and connecting cords are in a state
of good repair!
• Ensure air can circulate freely around the amp's ventilation slots at
all times!
• Never expose Switchblade to extreme heat or cold!
• Prevent the intrusion of dust and moisture!
• Always check peripheral gear's specs to ensure these accessories are
suitable for the amp.
• Never connect devices with high output signal Levels to
Switchblade's Input.
• Never operate the amp with Mains power that is too high or too
22
low. When in doubt ask the venue's sound technician or facility
engineer.
• Refrain from DIY repairs! Also have a qualified technician replace
internal fuses.
8 Troubleshooting
Mains connection: SWITCHBLADE
won't power up when you switch it on.
• It's not getting AC power. Check the Mains cord to see if it is
connected and firmly seated.
• The Mains fuse is defective. Ensure it is replaced with another fuse
bearing the same rating.
• The local Mains voltage does not match Switchblade's operating voltage
Available Voltages and How to Adapt Them
Switchblade ships in two versions rated for 110/120V and 220-240V.
You will find the rating indicated on the housing above the Mains
socket. Both models offer two operating voltages that are selected
using the voltage selector integrated in the Mains socket. Ensure that
the Mains voltage matches the voltage rating appearing in the voltage
selector window. This value is legible when the amp is in the standard
operating position, that is, placed right side up. The upright number
indicates the currently selected voltage, and the inverted number
indicates the alternative voltage. Check also the fuse ratings to ensure
they match the ratings indicated on the rear panel.
Voltage selection and fuse replacement may be performed by
experienced service technicians only. Accordingly, the following notes
are addressed exclusively to service technicians:
• Use a small flat screwdriver to remove the voltage selector from the
Mains socket.
• If the fuse is defective, replace it with a fuse bearing the specified rating.
• Turn the voltage selector and insert it back into the port so that the
desired Mains voltage rating is legible and appears at the top left
(next to the "Voltage Setting" arrow).
HEAD / COMBO 100