My Laney LC15R makes some intermittent hiss when using low gain (around 9 o'clock), engaging the bright switch eliminates this but I lose the sound I like. Any ideas what's causing the hiss?
Thank you.

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Pull the tubes out. Spray the pins with contact cleaner and work the tube in and out of the socket 3 or 4 times. Then seat it into place. Repeat until all tubes are done.
Failing that it may be a dry joint or any number of things including failing tubes. Would be worth trying your spare tubes but try simply cleaning it first.
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