FS: Speaker protector using solid state relay SSR
Speaker protector using solid state relay (SSR)
60 amp 300 volt mosfets. Good for 150WRMS into 4 ohms or 300WRMS into 8 ohms.
Requires a mains transformer 0-9 0-9VAC 5VA.
Holds off relay for 5 second for anti thump power up.
If DC is detected the relay is turned off and protect LED comes on until power is removed.
£9=95 each plus £3-99 p+p if UK or £10-99 p+p rest of world.
I built up a few for some disco amplifiers and some spares then never used them.
protect | harrabylad | Flickr
Speaker protector using solid state relay (SSR)
60 amp 300 volt mosfets. Good for 150WRMS into 4 ohms or 300WRMS into 8 ohms.
Requires a mains transformer 0-9 0-9VAC 5VA.
Holds off relay for 5 second for anti thump power up.
If DC is detected the relay is turned off and protect LED comes on until power is removed.
£9=95 each plus £3-99 p+p if UK or £10-99 p+p rest of world.
I built up a few for some disco amplifiers and some spares then never used them.
protect | harrabylad | Flickr
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Still 2 of each left.
The mains transformer pcb's have UK mains transformers on.
The ones without a transformer can have local mains transformers added i.e. 100VAC USA.
I have built up a new version with DC detect, over current detect and mains failure detect.
On power up SSR is held off for 4 seconds and on power down the SSR is disconnected.
There's a lot on the pcb so its not cheap but I am selling at cost of components.
Note UK mains only (230VAC)
£19-99 + £3-99 p+p to UK and £12-99 to rest of world.
On power up SSR is held off for 4 seconds and on power down the SSR is disconnected.
There's a lot on the pcb so its not cheap but I am selling at cost of components.
Note UK mains only (230VAC)
£19-99 + £3-99 p+p to UK and £12-99 to rest of world.
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Nigel,
I did see a post from a while back asking about a multi-channel speaker protector, that is, a board that can monitor and protect a 3 or, preferably, 4 way active speaker. Given many people have on this forum have actives, I wonder if you had ever considered such a design. It has the advantage of one PCB and not 3/4 for each amp with the commensurate space and wiring demands. A LED could indicate the faultamp, for example.
Is this a practical idea?
I did see a post from a while back asking about a multi-channel speaker protector, that is, a board that can monitor and protect a 3 or, preferably, 4 way active speaker. Given many people have on this forum have actives, I wonder if you had ever considered such a design. It has the advantage of one PCB and not 3/4 for each amp with the commensurate space and wiring demands. A LED could indicate the faultamp, for example.
Is this a practical idea?
It would be big and expensive so not a very attractive project.
For just DC detect my pcb is 100mm by 100mm.
My other pcb which does dc detect, over current detect and mains fail that is 160mm by 106mm for just one channel.
I already use an LED to show amp is in protect mode.
I spent a bit more time developing my dc detect, over current detect and mains fail detect protection circuit.
The over current detect can be set up using a trimmer from about 1 amp to 12 amps.
I got stuck into the software as it was taken from a simple DC detect protection circuit. It was quite easy before to just time things using instruction cycles. But with overheads of over current detect and mains failure this became inaccurate. I now use the PIC timer 0 to count up milli-seconds for dc detect and mains failure.
Mains failure now turns of the SSR and checks to see if mains returns before going through power up sequence again. This ensures system cant get stuck on a mains failure only to find mains comes back and is ignored.
Works very well now.
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