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P a g e
tight as they should. This can lead to noise and more commonly, sudden drops in
volume or complete lack of sound.
It is impossible to put a life expectancy on a valve but generally, if it lasts for the
first few weeks of use, a preamp valve can still give good performance for 3-15
years. Output valves tend to wear out much faster and with regular use, rehearsing,
practicing and gigging we would expect them to last between 1-2 years. We
recommend changing older output valves periodically as preventative maintenance,
i.e. before they fail and potentially cause more serious issues or pack-up mid-gig.
Victory ‘burn
-
in’ all amplifiers for a period of 2 hours at full power into dummy
loads to wheedle out any valves that are not up to the job. This is in addition to
around 90 minutes of electronic and audio test & measurement including a live test
at full volume in a sound-proof environment. This extensive testing catches most
problematic valves but a small percentage do fail in the first few weeks of use. If
you suspect a valve failure, please contact our service department who will advise
on the best course of action and invariably, replace these valves under warranty.
It is an easy task to re-tension the valve sockets and this can be done with a small
flat blade screwdriver such as this, (inexpensive watch-makers type):
Important! Please ensure the amplifier is not plugged into the mains and has been
off for at least 30 minutes before removing any valves so all of the high voltages
have dissipated. Carefully remove each valve in turn. The pre-amp valves have a
sprung-loaded screening can fitted over each one so twist these through 90 degrees
or so until they pop off. Then using the slow circular motion, pull the valve from the
socket. The output valves are retained by spring clips which need to be lifted up
and over the top glass nipple on the valves to facilitate their removal.
Please ensure that the valves go back into the same sockets as they are optimized
at the factory for best position relating to gain, noise, & microphony. This is easily
achieved if you just do one at a time; take it out, re-tension then re-insert and go to
the next one.
You will see that the valve bases have small 2-part metal clips in each hole and
these need to be pushed together to make a tight connection on the valve pins.
