No idea what PRS uses, but some info anyway…
Solder for electronics is typically 60/40 which is a ratio of tin to lead. It is usually rosin core, which has a soldering flux placed inside the solder to clean away contaminants during heating. This makes the joint clean and provides good contact. A better solder is 63/37, and known as eutectic solder because it turns quickly from a liquid to a solid and spends less time in what is known as the plastic region. 60/40 goes from liquid to plastic to solid. Movement of a joint during cooling can crystalize or fracture the solder (plastic region) making a poor electrical connection. Prevent movement during cooling to make a proper joint and don’t blow on it to cool it. Blowing causes movement.
Soldering on a wire or component merges the metals into a new alloy consisting of tin, lead, copper, etc. The outer surface of the wire for example is coated with solder at the molecular level. The wire is known as “tinned” and the solder cannot be wiped off even if reheated.
I recommend avoiding low lead solder because it can grow tin whiskers that can short out wiring and electronics. NASA lost some satellites from using low lead solder.
Silver solder in my experience is for jewelry work, and I think it requires a much higher melting point which might be the cause of your sound problem. The joint may be a poor electrical contact, otherwise known as a cold solder joint.
Overheating solder destroys it and ruins the electrical connection. A good joint should be shiny. A grey sugary looking solder joint was moved during cooling, and can be reheated to fix it. Overheated joints have black streaks and bubbles. These can be wetted with fresh solder, but should probably be sucked out and re-soldered.
Get the proper solder and re-solder the joints to address your issue. Hope this helps,
John
