I have a TS-850 that was modified extensively for ESSB and a DSP-100. I am using Behringer audio equipment for EQ enhancement. Here is the problem: When I transmit on 40m, I keep getting a heavy, thumping oscillating beat that continues even after I release my PTT hand switch. When I drop the gain on the Behringer preamp, it stops. Then I have to readjust the preamp gain control to get the rig to work without the oscillating. Of course, power drops considerably. I am running power from an AL-80B and use an "audio pecker" to tune the amp and antenna. This doesn’t happen on any other band. Just 40m. However, when I transmit into a dummy load, everything works perfectly on 40m. This confuses me. Is there possibly something wrong with my TS-850, DSP-100, or could it be just my tuner? I am new to ESSB , so any suggestions would be great. I will change tuners this evening.