TUBE 50/100 - MANUAL
5.0 TROUBLESHOOTING
1) The TUBE 50 / TUBE 100 is not getting any power:
•Check the mains cable to see if it is connected properly.
•The mains fuse may be defective. Replace the fuse with another identical fuse. If this fuse also trips, consult your Hughes & Kettner dealer.
•One of the secondary fuses may have tripped because the MIDI Module was installed incorrectly (reverse polarity). Once the rib-
2)The TUBE 50 / TUBE 100 is connected properly, but no sound is audible.
•One or several GAIN and MASTER controls are turned all the way down. Dial in a higher setting.
•The
•A short circuit in the speaker signal chain has tripped an internal fuse, or one of the power tubes is defective. Replace the speaker cable and have a qualified service technician replace the fuse/tube (identical specifications are a must). Please read Section 4.0 on how to replace tubes correctly.
3)AMP 1 or MODE A will not activate via the STAGEBOARD:
• The front panel selector switch is not in the "OFF" position. Set the appropriate switches to "OFF".
• The STAGEBOARD is not connected to the TUBE 50 / TUBE 100. Plug it into the appropriate jack.
• The MIDI module was previously active. Briefly press the MIDI LEARN button to clear the MIDI mode.
4)The sound is thin and muddy when the effects processor is
active.
•The signal processor is causing phase shifting that is added to the original signal in the parallel effects loop. Turn the
5)An annoying hum can be traced back to the RED BOX D.I. OUT.
•An electrical or magnetic field is causing interference. Use hig-
•Devices are connected to the RED BOX D.I. OUT in such a way as to cause a ground loop. DO NOT SEVER THE GROUND OF THE CONNECTED DEVICES UNDER ANY CIRCUMSTANCES!
Try plugging all devices into the same socket via an AC power distributor (power strip). If this does not eliminate the noise, you must ensure the connection is galvanically separated by routing the signal through a
6) You have connected the RED BOX D.I. OUTPUT jack to a mixing console and the signal is totally distorted, even when you have dialed in a clean sound.
•The RED BOX D.I. OUTPUT signal is overloading the mixing console's input. Reduce the mixing console's input sensitivity (GAIN). If this doesn't rectify the problem, patch the signal to the mixing console's LINE input.
7)You have connected the RED BOX D.I. OUTPUT jack to a mixing console and the signal level is way too low.
•The amp's output level is limited by an incorrectly adjusted POWER or other level control knob. Turn up the control or con- trols.
•The amp's output level is limited because the FX LOOP is active and the FX MIX control is turned up, but you have not connec- ted a signal processor to the loop. Switch the loop off, turn the FX MIX pot down, or patch in a signal processor.
•The mixing console's line input is not sensitive enough. Turn up the gain. If this is still insufficient, use the microphone input (if necessary, use an adapter cable or D.I. box).
8)When in use with a loud PA, the RED BOX D.I. OUT circuit causes feedback even though the amp is set to a low volume.
•Speakers connected to a tube amp may have microphonic pro- perties. On the TUBE 50 / TUBE 100, turn the POWER control up and the circuit will stop feeding back. You can also turn the PA/monitor down or reposition the amp.
9) The sound is slightly distorted and you cannot get a truly clean tone.
•The POWER control is turned down so low that the power amp is operating at minimum power, i.e. it is clipping even at low volume levels. Turn the POWER knob up and the preamp VOLUME knob down. Please see Section 3.2.
•The input section is being overdriven. Depending on the type of pickups in your guitar, this effect is very pronounced or may not be audible at all. If you don't want this slight distortion (although many players prefer a little dirt in their sound), reduce the volu- me of your guitar or volume pedal, turn the screws on the frame of your pickups so the distance between the strings and pickups is greater, or try a different combination of pickups.
•If the distortion has an annoying gritty edge to it, there may be some type of fault due to improper use of a signal circuit, for instance a speaker output connected to your amp‘s INPUT. In this case, consult your Hughes & Kettner dealer.
10)Compared with another amp featuring a similar power rating, the volume of the other amp is substantially louder than the TUBE 50 / TUBE 100 even though the respective
VOLUME/POWER pots are set to the same position.
•Please note that this type of comparison is only relevant when both VOLUME/POWER knobs are turned all the way up! Unfortunately, many amps are equipped with linear master volu- me controls, consequently they achieve maximum output power when the knob is set to somewhere around the 12 o'clock positi- on. We equipped the TUBE 50 / TUBE 100 with a logarithmic POWER pot, which gives you an evenly graduated power output curve. The headroom of the TUBE 50 / TUBE 100 is not fully exhausted until you turn the POWER pot all the way up.
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