Laney Lionheart L20H Manual page 9

L20H USER MANUAL - EN
TUBE AMPLIFIER SURVIVAL TIPS
• Tube amplifiers: generally, sound much warmer/sweeter than solid state transistor
amplifiers but they also need a little more respect due to the fragile glass tubes themselves.
The L20H uses top quality tubes, three ECC83 preamp tubes, and 4 x EL84 output tubes
which should give you years of trouble-free service, however like all tube amps; it is
important to treat it with a certain amount of care.
• Tubes are fragile glass components: they can easily be damaged if thrown in and out
of vehicles.
• Make sure the impedance: of your cabinets matches the setting on your amplifier.
Improper impedance matching will result in reduced output power output and compromised
sound at best and amplifier failure/premature tube failure at worst.
• Allow the amplifier: to warm up to room temperature before switching it on, the sudden
thermal shock generated can crack the cold glass tube housing plus any moisture is bad
news around high voltage electronics.
• Allow the amplifier: to cool down after playing before moving. Hot tubes are more
susceptible to damage than cool ones. Use good quality loudspeaker leads, cheap leads
are often not up to the job of handling the large requirements for loudspeakers and can
often short out.
• Tube amplifiers: don't like running into an open circuit. A tubes life expectancy is based
upon a number of factors which include operating temperature, how hard and how often
it is played, vibration due to travel etc. Tubes should be changed in your amplifier if you
notice any change in your amplifier's performance etc. They need not be changed at any
regular interval.
• Typical problems: with preamp tubes, can be a crackly noise, hiss, hum and micro-
phony. The preamp tubes can safely be changed with no other action required if they fail or
reduce in performance. Typical output tube problems can be blown HT fuse; sound lacking
in punch, sound lacks extreme highs or lows and low-level hum. The Output tubes can be
replaced singularly if you replace them with the exact same type AND grade as factory fitted
otherwise, they should be replaced as a set. See the diagram following to see how to check
the tube grade fitted. Exact replacement preamp tubes and matched sets of output tubes
are available from Laney via your dealer.
www.laney.co.uk
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