I have been trying to get my recently built Clarinet to work. It did not smoke , or smell and everything seemed ok except it did not play music. I checked all the parts to make sure they are correct,, and went over all the solder joints...still no sound. there is a faint hum. All the voltages are close to the amounts printed on the PCB. I built a Cornet , however it did not have the switching...could that be the problem. I am out of ideas. Thanks , Allan