Hi everyone. I have been accumulating experience in repairing many types of amplifiers for years now. After 10 years of experience, I have found that the only amps that give me random problems after doing routine repairs are only the big Korean SPL amps (zenon in particular). Most of the time, the repairs are successful and the owners are able to use the amps again for a long time without having problems, others instead (quite a few) come back because they explode all the time (sometimes the same bank, sometimes different banks without any logical sense). I often read that when this happens, a shorted or partially shorted inductor can occur (slightly pinched by electric arcs that arise under the peeling insulating enamel). The question arises spontaneously: how the heck can such a thing happen? and above all, typically, at which point of the inductor does it happen? I realize that many times, unrolling the whole inductor and rewinding it with new wire (of the right section) is really nerve-wracking and does not ensure optimal electrical and aesthetic results (especially because there are 2 or 4 amplification stages that must work in parallel. identically). Have you had these experiences? how did you solve?
Rewinding is a pain but if you have manufacturers who will not support the repair of their products, you don't have many options if you want to repair the amp.
Rewinding may look different but if done correctly (same number of turns, evenly distributed on the core, the electrical properties of the inductor should be the same. One exception is where the core reached extremely high temperatures (often obvious by a core color change). That can change the properties of the core and therefore the properties of the wound inductor.
When you wind, you have to pull every strand of the wire bundle down tightly as is done by the OEM.
Most of the failures that I've seen have been in the first wrap onto the body of the inductor by the terminal windings. Properly fixing the inductor body in place will help prevent this.
Deeper failures are likely due to a combination of thin enamel (too thin) and pulling windings down between other windings with too much force. Using a wire with better enamel will help prevent this.
Rewinding may look different but if done correctly (same number of turns, evenly distributed on the core, the electrical properties of the inductor should be the same. One exception is where the core reached extremely high temperatures (often obvious by a core color change). That can change the properties of the core and therefore the properties of the wound inductor.
When you wind, you have to pull every strand of the wire bundle down tightly as is done by the OEM.
Most of the failures that I've seen have been in the first wrap onto the body of the inductor by the terminal windings. Properly fixing the inductor body in place will help prevent this.
Deeper failures are likely due to a combination of thin enamel (too thin) and pulling windings down between other windings with too much force. Using a wire with better enamel will help prevent this.