Factory Settings And How To Restore Them (Factory Reset); Replacing Tubes, Service And Preventive Maintenance; When To Replace Tubes - Hughes & Kettner COREBLADE Mode D'emploi

7.3 Factory Settings and How to Restore Them (Factory Reset)

A factory reset is a seldom needed feature. Even so, be sure to read the explanation
carefully to ensure you don't accidentally delete your presets.
7.3.1 Triggering a Factory Reset
Pressing STORE and FX SERIAL simultaneously while powering the amp up
resets all settings, including the 128 MIDI-switchable presets and the basic MIDI
configuration.
CAUTION: This procedure is a last-resort option! It irrevocably wipes out all
stored settings. Before you trigger a factory reset, be sure to first create a backup
by copying your amp's internal memory to a stick.
7.3.2 Factory MIDI Defaults
A factory reset also restores the MIDI default settings:
• OMNI ON • MIDI channel: 1
• FX ON switched off • SERIAL deactivated
8

Replacing Tubes, Service and Preventive Maintenance

The C o r e b l a d e comes factory-equipped with EL34 power output tubes
that were subjected to a battery of tests, painstakingly selected, and matched using
Hughes & Kettner's Vacuum Tube Inspector. Ditto for its 12AX7 preamp tubes.
This unforgiving test regimen ensures optimum tone and utmost reliability.

8.1 When to Replace Tubes

The tubes in C o r e b l a d e are exemplary in quality, workmanship, and
long life. What's more, the TSC™ module ensures that even veteran power amp
tubes run at their optimum bias point, last longer, and sound better.
Telltale signs of wear are increased microphonics, noise and hiss, top-end
frequency damping, and poorer performance. These symptoms tell you it's time to
replace old tubes because they do take their toll on sound quality and indicate the
aging preamp or power tube will soon fail.
8.2 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? Spiking voltage
in the mains net can cause tube amps to drop out. Generators and faulty high-
current power circuits often produce such surges.
• Is the tube really defective or is it just a blown fuse? An old fuse, tube
de-ionization, or a flash-over caused by mains voltage power surge may have
tripped the fuse
8.3 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:
CAUTION: Tubes can remain very hot for quite some time and cause burns even
if the amp has been off for several minutes.
Pull the power plug on the back of C o r e b l a d e
minutes for power to dissipate! Then remove the rear panel. TSC™ adjusts bias for
you, and the HUM BALANCE trim knob is readily accessible from the outside,
so there's no longer any need to remove the chassis. Now you can carefully pull
out the tubes while gently pressing down on the clamps that hold them in place.
8.3.1 Replacing Power Output Tubes
You can use EL34s as well as 6L6GCs, and even mixed combinations. There's no
need to re-bias the amp - see chapter 6 for on this. However, we strongly advise
using matched tubes that share the same ratings.
CAUTION: Use 6L6GC tubes only! 6L6 tubes have different specifications and
may not be used in this amp. Check the label on the tube to make sure because
6L6GC are often referred to as 6L6s.
8.3.2 Replacing Preamp Tubes
Be sure to use the same type of replacement tube! You may have to adjust the
balance to reduce hum. To do this, proceed as follows:
• Select the CLEAN channel, turn VOLUME, TREBLE, and MID to the left
position, and turn BASS to the far right.
• Adjust the HUM BALANCE trim knob on the
panel until you find the setting that minimizes humming.
8.4 How to Prolong the Life of COREBLADE's Tube
• Never operate
• Never connect speaker cabinets with too high or low impedance!
• Always use high-quality, heavy-duty speaker cords that won't crimp!
• Use the STANDBY switch for short breaks!
• 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
• Prevent dust and moisture intrusion!
• Always check peripheral gear's specs to ensure they are suitable for the amp.
• Never connect devices with high output signal levels to
input.
• Never operate the amp with mains power that is too high or too low. When in
doubt ask the venue's sound technician or facility engineer.
• Refrain from DIY repairs! Always have a qualified technician replace internal
fuses.
9
Troubleshooting
Mains connection: COREBLADE 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
voltage.
Available Voltages and How to Adapt Them
C o r e b l a d e
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
and wait at least two rating appearing in the voltage selector window. This value is legible when the
amp is in the standard operating position; that is, sitting right side up. The
upright number indicates the currently selected voltage, and the inverted number
indicates the alternative voltage. Also check the fuse ratings to ensure they match
the ratings indicated on the rear panel.
C o r e b l a d e
C o r e b l a d e without connecting a load (loudspeaker)!
to extreme heat or cold!
C o r e b l a d e
C o r e b l a d e
ships in two versions rated for 110/120V and 220-240V.
15
's rear
's
C o r e b l a d e
's operating