I would still get an exchange for another PW2200, even if they where unable to produce the sound. If the problem still occurs with a new unit it may be your AC lines, or maybe just not a solid connection at the outlet. Check your electric outlet to be sure it is staying at a consistent voltage that is around 110 volts, if it is lower than that voltage, it might be the problem. If the voltage is highly variable, that could also be a problem.
Certain types of amplifiers are very intolerant of variable voltage or low voltage. The PS1000 uses a Class A/B amplifier, however the PW2200 uses a Class D amplifier. Being that it is Class D it may require more stable voltage to operate correctly, if the voltage where to spike or dip too low it may cause the amplifier to kick out some type of feedback momentarily. If it is your electricity that is the source of the problem, a power conditioner with voltage regulator may fix this problem.
Talk to your dealer and explain you would like to test that same model to verify if the electricity is or is not the origin of the problem. If they seem to have no problem getting the current PW2200 to work correctly they should have no problem taking it back and giving you a replacement unit.
Good luck.
