(Noob question) How do I set the bias? If it clears up the distortion that would be awesome! Anything before I return it or fork out money for repair...
It's not a noob question at all.
But fair warning - setting bias can be touchy and one wrong move (a slipping probe, turning a control too much) can cause more damage. If you're familiar with taking measurements and tweaking controls, you should be fine if you take things slow and are very careful.
Do the following with the amp unplugged and OFF:
You want to look for two bigger "emitter" resistors of value 0.47 ohms. You also want to look for two adjustment "pots". They're variable resistors that allow you to change the value by using a small screwdriver and turning the pot control.
Look to see where the pot controls are set currently - this is very important.
If your pots are like most on these units, they're likely dirty/oxidized and aren't providing the right value to the circuit. If (when the amp was on) your heat sinks are cold, this is the case. They should be quite warm to the touch. If they're ultra-hot and you can't leave your hand on there for a few seconds, that's also not right. They should be around 50C or thereabouts. But of course if the amp is unplugged and off like it should be now, they'll be cold.
The right long term thing to do is to replace these pots with new ones - preferably multi-turn pots that allow you to precisely set the values without risking a small change making a big resistance change. But if you don't want to go there just yet, what can work as a temporary fix is to exercise the pots (turn the controls back and forth to remove some of the oxidation and "clean" the controls a bit). So the reason you want to note where the pot is set currently is because after you exercise the pot a bunch of times, you want to return it to the original position. Don't exercise the pots with the amp on - only with the amp unplugged and off.
You can place small clipping probes on either side of one of the 0.47 ohm emitter resistors and set your DMM to DC voltage mode. What you'll eventually read will be in the mV range.
If you've successfully exercised the pots and set them back to the original position and set up your probes across the emitter resistors, then go on.
Plug your amp in and turn it on.
Read the voltage across the emitter resistor. It should be ~70mV. If it's lower and somewhat close to this value (say 40-50mV or higher, but below 70mV), I would just wait to see if the heatsink on that side of the amp warms up. If it does and it's fairly warm, but not really hot, you may want to leave it. If it's cold or really hot, you can slowly adjust the pot control - I believe counterclockwise will make it go down, clockwise up. You'll see the effect of the movement on the voltage. Be conservative and set it to say 40-50mV and see how hot the heatsink gets.
Check the other emitter resistor and repeat the process.
When I got my amp, both heatsinks were cold. I exercised my pots and set bias, and got the heatsinks warmed up nicely. But even with the heat sinks cold, there was no distortion and it actually sounded fine. Since I set the bias a few months ago, one of my heatsinks has gone cold again. Exercising the pots to "clean" them doesn't necessarily last. I need to replace my pots as a long term solution.
If the above all sounds pretty intimidating, I wouldn't mess with it yourself. You may want to post your location and see if there's a local AK'er whose set bias before and can help you.
in comparison to the 400A, which has a tube-like reputation, the Forte is more in your face and a touch harsher, but that's not necessarily a bad thing as i think some people would find the 400A too laid back and warm. one thing that surprised me was how light the Forte was in comparison to most 200wpc amps - it's probably about 35 lbs. build quality is still perfectly acceptable, though.
