DC blockers - what's your experience

Should point out that the thing DC blockers fix the most is mechanical transformer hum.  99% of the time it does not affect the electrical output.

this is correct and consistent with my experience

reality is, dc in the powerline is a reality for most, in modern homes, with modern electronics, lighting and appliances...

My experience of using a few different DC blockers is they seem to choke the transient impact, bass and speed of the power amplifier.

If you have DC issues, like I did in my last apartment, they can make the sound cleaner and clearer, but with the above mentioned negatives. So they give and take away.

If you have no DC issues, like in my current house, they just become a net negative and your system is better without them.

I have noticed that in my area the DC on the line situations come and go, when they occur they persist for a few weeks. Whenever there's a holiday, that's when it starts and persists.... the cause is most likely overloading of the entire neighborhood, and it got much, much worse since the outbreak of the pandemic with most people staying at home / working from home / losing jobs & full time at home watching TV and hanging on all times to their electronic devices.

The most practical solution I found is to bleed the DC when it happens with a parallel inductor (Richard Grey - RGPC makes such device, for example). Then I get a major improvement in sound quality in all areas.

However, when there's no DC on the line, I keep the RGPC off.

This way I can avoid the negatives of a series DC blocker...

DC causes my amps toroidal transformer to buzz fairly loudly. The only time it happens is when my wife uses this one particular space heater.

I think DC on an AC circuit in the US is very rare and is often blamed for buzz when it is something else.