Acoustic 120 Head in with damaged output transistors.. blownBass is open to act a as a heat sinkPower amp and drive transistors.. all blow.I tried reparing this several times and each time when the amp was driven hard the output transistors went… taking the drive trasnsistors and several resistors with them,…After the PA board became damaged with repeated soldering I gave up and stripped her out..And installed this 250 Watt Class D module which with this power supply should give 220 Watts into 4 Ohms and 110 Watts into 8 OhmsSimple neat install with it being a very efficient amplifier it only needs a small heat sink…Testing her out and she works very well with the Acoustic Preamp! all sounding good with my Jazz BassBack together and ready to ship to the customer This amp has caused me trouble.. the Power amp section blew transistors frequently.. in the end I went for a new power amp module (Class D) and she is sounding sweet again!