Though a guitar amplifier's microphonics distortion is sometimes appreciated as part of the " special sound " of a guitar amplifier, a faulty vacuum tube or other component can cause out-of-control positive feedback.
12.
Since the higher output AC30 / 4 shared its preamplifier design with the lower powered AC15, Vox discovered the high-gain EF86 tube was susceptible to microphonics, or even failure, when exposed to the increased vibration present in this uprated amp.
13.
A coil or capacitor which emits acoustic noise will, conversely, also be microphonic, and the high-end audio industry takes steps with coils and capacitors to reduce these microphonics ( emissions ) because they can muddy a hi-fi amplifier's sound.
