so this has been bugging me for about three weeks now. i picked up my 7300 after a lightning storm (not a direct hit, just nearby, had everything unplugged but apparently not fast enough) and ever since then the audio on transmit sounds like garbage according to everyone on the repeater and on 40m SSB. i can hear myself fine in the monitor but people are saying its like... clipped and buzzy? one guy said it sounded like i was talking through a tin can underwater which is a bit much but ok.

i pulled the mic gain down thinking maybe something got fried and was now overdriving but that didnt help. tried a different mic too, same thing. RF power output looks fine on the meter, SWR is normal, receive is totally normal. just the TX audio that's messed up.

my first thought was the finals but if the power output is normal would the finals even cause an audio distortion issue? or am i thinking about this wrong. wondering if something in the modulator section or maybe the DSP board took a hit. anyone dealt with something similar after a storm event?

yeah the finals being fine but audio being trashed actually points pretty strongly away from the PA stage, you're right to second-guess that. what you're describing — clipped buzzy audio with normal power — sounds more like something in the baseband processing path. on the 7300 i'd be looking at the main board around the audio input and modulation circuitry before assuming DSP, the DSP failures usually show up in weirder ways like the waterfall going nuts or the radio locking up.

did you check if the ALC is doing anything weird? sometimes after a surge event you get a component thats partially cooked and the ALC starts oscillating or misreading which can cause exactly that clipping effect even at low mic gain. worth putting it on a dummy load and watching the ALC meter while you talk. if it's jumping all over the place before you even get loud that might be your culprit area. icom service manual for the 7300 is actually pretty accessible, the schematic isn't terrible to follow if you're comfortable with a DMM and oscilloscope.

had almost the exact same thing happen to a friends ft-991 after a storm, turned out to be a cap on the audio board that had gone leaky. not totally dead just... wrong. took forever to find because everything kinda sorta worked. if you have access to a scope and can probe around the audio chain while keyed up on a dummy load you might see it pretty fast, the waveform will look ugly right at the bad component.

also just worth asking — have you tried doing a full factory reset on the radio first? i know it sounds dumb but sometimes a near strike can corrupt settings in ways that are really non-obvious and a reset costs you nothing. probably not your problem but takes 30 seconds so.