Dear fellow Marshallers,

I have recently bought a Marshall DSL15C amp for my guitar and was looking to use headphones for silent practice. I tried disconnecting the amp output on the back side of the speaker and plugging in my headphones instead - this doesn't seem to work perfectly as my headphones only play in one ear and the sound is crazy high. 

Is there a good way to use headphones on this amp or do I need to buy another amp for silent practice?

Rock on,

Magnus