I have an old audiopro mos 1200. it was made by yorkville and weighs 56lbs. It is a mosfet design and has 600x2 into 2 ohms or 1200 bridged into 4ohms. The fan is very quiet. It is not a class D amp but a class A/B. From what I've been told is about 10yrs old. The amp is always on due to a malfunction in the on/off switch. It is a pro amp . Also as of recent one channel does not work. It is in bad shape but one channel is working good. for 600at 2ohms and in its current condition I will sell at $50US. I bought it $300 used Canadian. I would prefer local sale but I can meet half way. it is no good to me as I have bought a new amp. Second I have a pair of 6" port flares left over from a project I never ended up doing. I will sell for $50US(cost) and if you need some 6" pipe I got that too. just email or pm or reply here.