I have one of the ebay China speaker protection relay boards on my Class D amp currently. I've read of contacts welding when using relays to protect from DC. I guess I could test this by running one of the plus or minus 70 volt rails into a 2-4 ohm load and cycling the relay several times to see if welding will happen. I've read mixed opinions on the reality and likelihood of this.
I have seen a triac crowbar work exactly as designed (Peavey CS series power amps) to cut power to the speaker. This tends to take out additional power transistors (unfortunately sometimes rare obsolete ones at that). I do trust that it'd save the speakers, but I see the triac crowbar complained about since it does destroy yet more transistors when one or more have failed.
Is there a better way that's "more reliable" than a relay and less damaging than a crowbar?
I have seen a triac crowbar work exactly as designed (Peavey CS series power amps) to cut power to the speaker. This tends to take out additional power transistors (unfortunately sometimes rare obsolete ones at that). I do trust that it'd save the speakers, but I see the triac crowbar complained about since it does destroy yet more transistors when one or more have failed.
Is there a better way that's "more reliable" than a relay and less damaging than a crowbar?
Yes, using mosfets as a solid state relay.
This thread may be of interest: https://www.diyaudio.com/community/threads/rtr-ssr-speaker-protection-gb5.392399/
This thread may be of interest: https://www.diyaudio.com/community/threads/rtr-ssr-speaker-protection-gb5.392399/
Last edited:
Check https://neurochrome.com/products/guardian-86, he has great protection circuit. His design are top notch and he’s a pleasure to deal with.
sB
sB