Has anyone built Rod Elliott's speaker protection circuit ?
Here is the design:
Loudspeaker Protection and Muting
Has anyone used it with 15 Volts DC ? I am building this and had a couple of questions before I solder in the parts, since it makes it very difficult to correct PCBs once they are already populated.
I DO have his full build site which gives component values but since it is copyrighted, unfortunately, I cannot give that information out. But for anyone who has ALREADY bought his product and built them, the site is available.
What I want to know is, with 15V DC as the power supply, what should the values of C4 & R8 be to give a start up delay of AT LEAST 8 seconds. I was thinking about 100uF and 120k but I am not sure if those are correct.
Thanks
Here is the design:
Loudspeaker Protection and Muting
Has anyone used it with 15 Volts DC ? I am building this and had a couple of questions before I solder in the parts, since it makes it very difficult to correct PCBs once they are already populated.
I DO have his full build site which gives component values but since it is copyrighted, unfortunately, I cannot give that information out. But for anyone who has ALREADY bought his product and built them, the site is available.
What I want to know is, with 15V DC as the power supply, what should the values of C4 & R8 be to give a start up delay of AT LEAST 8 seconds. I was thinking about 100uF and 120k but I am not sure if those are correct.
Thanks
Has anyone built Jan Didden's protector system for the pax amplifier ? Here is the schematic & information:
https://linearaudio.nl/sites/linearaudio.net/files/UK-3 2008050501.pdf
I would like to use its parts which only perform speaker DC protector and instead of the amplimo relay, I would like to use Rod Elliott's Mosfet relays. The good thing about this design is the use of upc1237 and the fact that it 'latches' when a fault is detected, which is what I would like.
If I keep the supply voltage at 44 volts (as in his design), I presume I would be able to keep pretty much all the existing R & C values without having to make drastic changes.
I also intend to monitor BOTH channels on the board.
What I am not sure is, how to terminate the ends which go to the other modules, namely ProtN & ProtP. Should these be just left open circuit and OL pin on uc1237 simply grounded ?
Thanks
https://linearaudio.nl/sites/linearaudio.net/files/UK-3 2008050501.pdf
I would like to use its parts which only perform speaker DC protector and instead of the amplimo relay, I would like to use Rod Elliott's Mosfet relays. The good thing about this design is the use of upc1237 and the fact that it 'latches' when a fault is detected, which is what I would like.
If I keep the supply voltage at 44 volts (as in his design), I presume I would be able to keep pretty much all the existing R & C values without having to make drastic changes.
I also intend to monitor BOTH channels on the board.
What I am not sure is, how to terminate the ends which go to the other modules, namely ProtN & ProtP. Should these be just left open circuit and OL pin on uc1237 simply grounded ?
Thanks
Do you mean an amplifier with +15V and -15V split rails, or some kind of full bridge class-D amp that runs from a single +15V rail?
Rod's circuit won't work for the latter as there is no ground reference to connect D5 and D6 to. The 'ground' on a single rail amplifier is effectively the negative supply rail with respect to the speaker output.
For +/-15V operation it'll work just fine as is.
Rod's circuit won't work for the latter as there is no ground reference to connect D5 and D6 to. The 'ground' on a single rail amplifier is effectively the negative supply rail with respect to the speaker output.
For +/-15V operation it'll work just fine as is.
No, Didden's board works off simply a 45V SINGLE DC supply, which I can build simply using a very small 30V AC transformer with a rectifier. Single supply is enuf. Pls check the circuit.
As for Rod's P33 board, even tho it is great and that ALSO works with a single supply, because of its non latching nature, I prefer to use Didden's circuit using the upc1237.
For the Mosfet relays, I will use Rod's P198, which simply uses a photodiode. It can work with any supply.
Thanks
As for Rod's P33 board, even tho it is great and that ALSO works with a single supply, because of its non latching nature, I prefer to use Didden's circuit using the upc1237.
For the Mosfet relays, I will use Rod's P198, which simply uses a photodiode. It can work with any supply.
Thanks
Diddens circuit has the same limitation - the ground of the protection rail must be 0VDC with respect to the speaker output.
If your amp is powered by a single rail, the output becomes halfway between the positive rail and ground.
E.g. the typical Class-D amps you find powered by say a +24VDC wallwart will measure approx +12VDC on the speaker terminals with respect the ground terminal of the DC power barrel jack. Since both terminals of the speaker are at +12VDC no dc is passed through the speaker but hooking up these protection circuits will cause them to be constantly triggered.
At a glance, Diddens circuit requires an amp with split rails (+Ve, -Ve and ground supply rails) but the UPA1237 chip only requires to be connected between +Ve and ground. It won't work for a single supply amp where there is an intentional DC offset between both speaker output terminals and supply ground as there is no ground supply rail which is at the same voltage as the speaker terminals.
Rod's circuit requires requires an amp with split rails and connections to both +Ve, -Ve and ground supply rails. It won't work with a single supply amp either for the same reason - there is no where to connect the ground reference.
If your amp is powered by a single rail, the output becomes halfway between the positive rail and ground.
E.g. the typical Class-D amps you find powered by say a +24VDC wallwart will measure approx +12VDC on the speaker terminals with respect the ground terminal of the DC power barrel jack. Since both terminals of the speaker are at +12VDC no dc is passed through the speaker but hooking up these protection circuits will cause them to be constantly triggered.
At a glance, Diddens circuit requires an amp with split rails (+Ve, -Ve and ground supply rails) but the UPA1237 chip only requires to be connected between +Ve and ground. It won't work for a single supply amp where there is an intentional DC offset between both speaker output terminals and supply ground as there is no ground supply rail which is at the same voltage as the speaker terminals.
Rod's circuit requires requires an amp with split rails and connections to both +Ve, -Ve and ground supply rails. It won't work with a single supply amp either for the same reason - there is no where to connect the ground reference.
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Both circuits would be fine since my amp has +/- 85 volts DC dual supply. But since that voltage is too high, both the protector circuits would be fed by a separate txformer whose 0 volts would be tied to the the same 0 volts of the amp's power supply.
I just noticed something which I do not understand.
Unfortunately the datasheet for upc1237 does not explain the operation of the chip thoroughly.
I assume that pin 6 is low under normal circumstances such that enough current sinks thru it to activate a normally open relay so that speakers are connected. When a fault occurs, pin 6 must go hi (or infinite resistance to the ground) so that the current thru the relay coil stops and hence the relay is disengaged.
Instead of a relay coil, I am attaching Rod Elliott's P198 Mosfet relay between Vcc & pin 6 to eliminate DC arcing. Mosfet relays only needs about 15 mA max to switch the mosfet on FULLY.
What I do not know is, when a fault occurs and pin 6 goes hi, what value of voltage or resistance it reaches ? The reason I am asking is because to turn the Mosfet relay off, less than 0.5 mA must be allowed. Does pin 6 behave in such a way that it inhibits all the current ?
None of the datasheets mention that.
If anyone knows, please explain.
PS: My Vcc is 45 VDC, and I am using Jan Didden's circuit specified here:
https://linearaudio.nl/sites/linearaudio.net/files/UK-3 2008050501.pdf
Unfortunately the datasheet for upc1237 does not explain the operation of the chip thoroughly.
I assume that pin 6 is low under normal circumstances such that enough current sinks thru it to activate a normally open relay so that speakers are connected. When a fault occurs, pin 6 must go hi (or infinite resistance to the ground) so that the current thru the relay coil stops and hence the relay is disengaged.
Instead of a relay coil, I am attaching Rod Elliott's P198 Mosfet relay between Vcc & pin 6 to eliminate DC arcing. Mosfet relays only needs about 15 mA max to switch the mosfet on FULLY.
What I do not know is, when a fault occurs and pin 6 goes hi, what value of voltage or resistance it reaches ? The reason I am asking is because to turn the Mosfet relay off, less than 0.5 mA must be allowed. Does pin 6 behave in such a way that it inhibits all the current ?
None of the datasheets mention that.
If anyone knows, please explain.
PS: My Vcc is 45 VDC, and I am using Jan Didden's circuit specified here:
https://linearaudio.nl/sites/linearaudio.net/files/UK-3 2008050501.pdf
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