I would like to help out all SWR Workingman's 12 and 15 combo owners with a tech tip. I own both models and noticed my 15 was running way too hot compared to my WM12. After looking around the web I found that there is an internal bias trim pot to balance some transistors. After a visit to Fullcompass's service department this week here in Madison, WI my bias on the WM15 was properly adjusted. Problem solved and took 1 hours service time. Before I could not touch the heat sink on my WM15, now the heat is barely perceptible. Photos are of my current home setup, SWR WM15 on one end and Acoustic Control Model 126 combo on the other end of my room connected with a Roland Micro Bass RX as preamp controller in stereo.