A bit of History. I have a HA3500 that I love, but the fan went out while playing and the Amp Module got damaged. It now "Farts" out after 20 minutes or so at volume. Part is only $60..No problem. BUT!!!!!! I bought a complete HA5500 rig for $200 with a 4x10 and a 1x15. The 5500 has a burnt module like the 3500 and a bad tube pre amp circuit. Solid state side works fine. So here is the question. Can I use my 3500 pre amp board with the soon to be new module board and the 5500 power amp? Hartke tech said He was unsure. I said they both have 3500/5500/7000 printed on the PCB. Anybody really know? NOT guessing..But really know?