Hughes & Kettner Statesman QUAD EL84 - Manual (Page 12)

Statesman Series
12
Absolutely pay attention to preparations and chronological
order!
1. Turn off the device
2. Exchange tubes
3. Remove all jumpers
4. In tubes with the same characteristic curve, do not change the
position of the bias trimmer. In tubes with unknown characteristic
curve, turn the bias trimmer to the right-side stop (lowest current).
5. Turn on the device
6. Measure and adjust the bias current (equivalent voltage):
The jumpers bypass a shunt resistor. When removing the jumpers,
the cathode current can be determined via the exposed pins through
a voltage measurement. The following applies in this connection: 1
mV is equivalent to 1 mA. The order of the jumpers from left to right
corresponds to the order of the appurtenant tubes from left to right.
The bias current is correctly adjusted if a voltage between 16 and
21 mV is applied to the pins (between the upper and lower pin of
the respective jumper) with all tubes. If this voltage range cannot be
adjusted to all tubes, the divergent tubes must be exchanged and a
suitable tube must be found. For this reason Hughes & Kettner offers
selected tube sets with similar characteristic curves.
7. Turn off the device
8. Put on all jumpers. Attention: Do not forget to put the jumpers
on again after successful alignment! Never operate the amp without
jumpers!
9. Turn on the device
10. Carry out hum balance Basic setting: Switch the amp to CLEAN,
turn VOLUME, TREBLE and MID to the left-side stop, and turn BASS to
the right-side stop. With the help of the trimmer, look for a setting in
which the lowest humming emerges.
11. Mount the protective grid again
4.
Possible Error
Sources / Troubleshooting
Mains connection: STATESMAN 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 Statesman’s operating
voltage
Available Voltages and How to Adapt Them
Statesman 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).
Statesman is connected properly, but no sound is audible.
• The guitar’s VOLUME knob is turned all the way down.
• The amp’s VOLUME knob is turned all the way down.
• The effects loop is active and set to SERIAL, but no effect device is
connected.
• The anode fuse has blown. Ensure that it is replaced with a fuse of
the same rating.
• The fuse for the tube heating tripped (the tubes don’t glow). Ensure
that it is replaced with a fuse bearing the same rating.
The amp makes ringing noises when
played and tends to Feedback.
• One or several tubes are microphonic. Replace the defective tube
with another of the same type.
Signs of tube wear such as increased microphonics and
noise, Treble loss, weak power output or muddy sound begin
reappearing just a few hours after replacing tubes.
• The wrong tubes were installed when old tubes were replaced or
the amp was not biased properly. Take the amp to a professional to
correct the problem.