The input jack is probably grounding or has a bad ground. it probably has a bad solder joint on the jack to the circuit board. if you can open it up gently look at the pins of the jack to the pcb. make sure the battery is disconnected! dont want to short anything out. it may be hard to see, but you can push on the jack and see if the legs/pins move, etc. humming and buzzing sounds usually are a bad ground. especially on a unit this small. yostamplifier.com
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The input jack is probably grounding or has a bad ground. it probably has a bad solder joint on the jack to the circuit board. if you can open it up gently look at the pins of the jack to the pcb. make sure the battery is disconnected! dont want to short anything out. it may be hard to see, but you can push on the jack and see if the legs/pins move, etc. humming and buzzing sounds usually are a bad ground. especially on a unit this small.
yostamplifier.com