I wonder if PCB layout affects the amount of interaction between the two halves and hence the noise. I seem to get far less whine with Melzi and A4988 but the switching waveforms for A4982 should be exactly the same. I think the only difference is that it has better short circuit protection.
They both have the same fixed off time so the on time is defined by the current and the motor voltage / supply voltage ratio. I made a Huxley version of the Mendel90 with NEMA14 motors and took it to a local 3D printer group. The younger members complained about a high pitch whine but it was above my hearing. The smaller motors must have lowered the switching frequency.
They both have the same fixed off time so the on time is defined by the current and the motor voltage / supply voltage ratio. I made a Huxley version of the Mendel90 with NEMA14 motors and took it to a local 3D printer group. The younger members complained about a high pitch whine but it was above my hearing. The smaller motors must have lowered the switching frequency.