Over the weekend I was tinkering with my pop's system and noticed the left channel sounded a little dull. I narrowed it down to the preamp. I opened it up and cleaned it out and noticed one of the mosfets looked like it had some heat damage. I tested it with a multimeter and it read the correct voltage. Has anyone ever had to replace a faulty mosfet, and would it cause the sound to be dull and lifeless? He's going to be getting a new preamp pretty soon (probably a musical fidelity
) and the hafler will be in my posession... so I'll be the one repairing it.