That's not entirely true, so I have to defend Topping a little.
With the L30, a maximum of 3-5 cases are known where headphones were damaged.
This initially had nothing to do with DC in the music signal, but only with the ESD sensitivity of the devices.
DC protection was actually installed, but it was discovered at the time that the DC protection did not respond quickly enough. There were also coupling capacitors at the input.
Also, this ESD problem came together due to several unfortunate technical circumstances and in reality only a few units were even affected under unfortunate circumstances. Among other things, it was the perfection of Topping that caused the problem in the first place.