Speaker Protection Kit for under $5

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silverprout

silverprout

Member
Joined 2008
AndrewT said:
You are reading but not assessing the content. Read and understand and discard the chaff.
Waiting for the DC on the power supply to sag enough to allow the relay to drop out could take 10000ms, or if you arrange for a very low charge storage one could get down to maybe 1000ms
Too slow, by more than a decade and could be three decades slower to isolate.
Click to expand...

"delay to ON and instant OFF isolates the speaker before tha amplifier starts to shut down."

With this solution the relays are off way faster than the amplifier starts to shut down (especially if you add a regulator and very sensitive relays).

PS : You could perhaps try a 7805... and measure the delay ?
 
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A

AndrewT

R.I.P.
Joined 2004
silverprout said:
"delay to ON and instant OFF isolates the speaker before tha amplifier starts to shut down."

With this solution the relays are off way faster than the amplifier starts to shut down (especially if you add a regulator and very sensitive relays).

PS : You could perhaps try a 7805... and measure the delay ?
Click to expand...
I have already implemented slow release and faster release and Bonsai's NX PSU with a very fast release.
But loss AC detection is far faster than any of those.
I have the PCB kit as being discussed in this Thread. It is potentially slow because it does not have loss of AC detection.
If it were powered from the Main PSU to avoid the cost of a separate low voltage transformer, then it becomes far too slow.

Sajti's post34 sch with a separate transformer and low charge PSU can be made acceptably quick for a power amp isolation. But may still be too slow for a fast reacting source that shuts down very quickly. I know I have tried it and used it.
 
silverprout

silverprout

Member
Joined 2008
AndrewT said:
I have already implemented slow release and faster release and Bonsai's NX PSU with a very fast release.
But loss AC detection is far faster than any of those.
I have the PCB kit as being discussed in this Thread. It is potentially slow because it does not have loss of AC detection.
If it were powered from the Main PSU to avoid the cost of a separate low voltage transformer, then it becomes far too slow.

Sajti's post34 sch with a separate transformer and low charge PSU can be made acceptably quick for a power amp isolation. But may still be too slow for a fast reacting source that shuts down very quickly. I know I have tried it and used it.
Click to expand...

I've designed a circuit by myself because it seems extremely difficult to detect defects in the AC.
When the stormy weather is here, there are some erratic small and fast series of power cuts, and all boards that i've buyed (including mainstream market amplifiers) or designed are in trouble.
How can you differtiate small cutted and distorded sinewaves of the regular distorded and dephased sinewaves please ?
 
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sajti

sajti

Member
Joined 2003
This is my protection pcb. 2sec turn on delay, DC detection, overtemperature protection. The PCB fixed by the speaker terminals. It gets 12V power from the ribbon connector, and it feeds the relay of the inrush current limiter.

Sajti
 

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