Description, of
this pedal (Broadcaster-AP) is:
"The control layout features both LEVEL and GAIN TRIM potentiometers and a switchable high-pass / low-cut filter – 100Hz @ 6dB/oct. The GAIN TRIM control has 12dB more gain than the low-gain side of standard Broadcast, allowing the Broadcast-AP to cover ground from clean boost through to medium gain overdrive tones. In addition, the gain of the pedal can be increased via an internal trimmer and – when pushed to the max – the sound becomes overloaded, broken and fuzzy. The high-pass / low-cut filter can help keep the low end together, especially when driving amps at higher gain and volume levels."
Kind of a high-quality, broken-speaker, bad/overloaded-board-preamp sound, I would look for broken speaker-like components -- a fuzz that leaned more toward the broken speaker sound instead the overdriven amp sound. I would try keeping a good percentage of the clean sound mixed in -- maybe a shunt around the pedal. You could use the Low Cut control on the chosen fuzz pedal to match the "high-pass / low-cut" filter in the Broadcast-AP pedal. (maybe the "Master Fuzz"
Maestro Fuzz-Tone FZ-1A pedal, used in "(I Can't Get No) Satisfaction"
Then, I would add to it with the Speaker parameters, Speaker Drive, Speaker Compression, Speaker Compliance and Speaker Time Constant. If I still felt something was lacking, I would look at Xformer Matching, Voice Coil Resistance and Xformer Drive. And especially, the Cab Preamp -- as
@Joe Bfstplk previously mentioned, I would try Transformer and Tube Types along with the Drive and Saturation parameters. And, paradoxically, I would try out the High-Quality preamp settings, even though we are munging the tone with it.
I am guessing this distortion tone has it's linage in the original 1961 Grady Martin broken-channel-strip sound. All of this is kind of a hack to match the pedal. But, it could actually end up sounding better -- with access to all of FAS's amp/transformer/speaker/cab/mic-preamp parameters. The pedal is a actually a hack to match the clipping and transformer distortion of the bad channel-strip. My guess is that a lot of the sub-harmonic and octave sounding tones will appear on their own.
But First, I would start with "Master Fuzz" Maestro Fuzz-Tone FZ-1A pedal, shunt around it with a clean signal, and cut down the pedal's bandwidth with the Low Cut and the High Cut on the pedal. I would also experiment with the pedal's Graphic EQ and Advance parameters.
With the FM9 or the FX3 you could devote a whole other amp to this sound. Obviously, it will be trickier with one amp in an FM3.