Hi, I have an acoustic guitar which also has a piezo-electric (?) pickup. I don't have an amp to play the electric function but I heard that regular computer speakers with independent power supply can be connected to the guitar with a 3.5mm -> 6.3mm jack converter. I bought a 6.3mm connecter and plugged in the speakers to the guitar but there's no output to the speakers and the guitar plays like it does normally on acoustic mode! Any idea where I'm going wrong? Thanks.