Crowbar can't function with low voltage power supply.
Crowbar can't act as delay circuit.
Crowbar contact is a catastrophic failure.
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If you mute first the amplifier than you can use crowbar to protect the speakers without risk for the amplifier, and can be used to reduce the noise generated during startup but only if the amplifier schematic is well made.
Crowbar working from 8 V DC and 100% safe to protect your Speaker and, parts cost 2 USD
Delay circuit ist very simple, also about 3 USD parts count if amplifier is not well designed to avoid turn on off thumps, have seen last 20 years a lot of rubbish schematics from Hi-Fi designer
an failed amp is catasttophic failure and need reliable DC
Protect
please update Hi-Fi skills and learn from other
risk for amplifier short Output to Ground same crowbar does with full Output power?
,...come on LOL,
Then its rubbish not well designed amplifier !!!
Throw it away or use as doorstep.
Designer need to learn from other to add protection and not copy and paste schematics without understand basics.
I can short amplifier everytime and anytime with full load output power same crowbar does and all is fine.
after remove short, the amplifier play again music and hundreds of people can dance
No problem to short amplifier welll designed with 25 A Output current and > 100 V AC Output voltage.
After remove short amp start automatic Player again music.
By the way ...Crowbar risk for amplifier at Hi-Fi Level Output Power
Come on Lol
After remove short amp start automatic Player again music.
By the way ...Crowbar risk for amplifier at Hi-Fi Level Output Power
Come on Lol
A well designed crowbar protection is the most reliable protection for the speakers, and a good amplifier design will not have any problem with it.
Completely agree @NMOS.
Completely agree @NMOS.
Project 120
'' Needless to say, using the circuit with supply voltages less than around 40V is not recommended, as you will have a false sense of security. ''
'' Needless to say, using the circuit with supply voltages less than around 40V is not recommended, as you will have a false sense of security. ''
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For those who think the Crowbar is the better method, how about they start their own thread where they can share their designs/schematics/boards and extol the virtues of that design rather than taking drive by pot shots in an existing thread about an alternate method.
LKA was good enough to publish his working design and yet people get on this thread every so often to criticize and boast that their design is better.
Talk is cheap and as I said previously, show us your design or start your own thread.
Better still, ask your self why you are posting????
If your comments are NOT constructive, you have a problem with your character, that you need to correct!
Talk is cheap and as I said previously, show us your design or start your own thread.
Better still, ask your self why you are posting????
If your comments are NOT constructive, you have a problem with your character, that you need to correct!
I haven't really considered the crowbar approach as there has been some, possibly unwarranted, criticism of its shortfalls. It would take time that i don't have, to understand those comments so I have stuck with "if it ain't broke, don't fix it" approach.
So I have used the conventional spkr protect topology developed by Silicon Chip, and others on this forum and even some "esteemed"
amplifier book authors, for well over 18 years. The approach is very simple and many have used the same configuration of trannies but with different caps and resistor values to achieve the same thing. I have played with some of the values but many of the changes have made no difference. The main components to "play" with are those setting the start-up time.
I also have the mainly "diode-based" version but haven't focussed on it since I have plenty of signal transistors and what I have has worked Ok.
I took out the mechanical relay a while back and replaced it with the Si8752 and MOSFETS, using information and recommendations from Rod Elliot's articles, another thread here, and the application notes, and have been running it for a decent period of time with no issues. The amplifiers it is used with, use MOSFETS as outputs and are 50 - 100W rated output but I never crank them up as my old speakers have 93db sensitivity so they generate a lot of sound.
The circuit is, as i said, conventional and the mechanical relay is replaced by the 680R resistor and Si8752s and MOSFETS. It will run on amplifier supplies from 40 - 60V comfortably as the circuit has its own ~30V operating voltage via the linear regulator (MJE3055 + zener). The MJE3055 can be heatsinked if necessary. The board size is 68 x 85mm for a stereo setup and I have played around with different layouts to try to better match the amplifiers geometries and associated other components. When i get back to a PC on my network, i will try to find the board drawings.🙂
View attachment SpkrprotectwMOSFETs.pdf
So I have used the conventional spkr protect topology developed by Silicon Chip, and others on this forum and even some "esteemed"
amplifier book authors, for well over 18 years. The approach is very simple and many have used the same configuration of trannies but with different caps and resistor values to achieve the same thing. I have played with some of the values but many of the changes have made no difference. The main components to "play" with are those setting the start-up time.I also have the mainly "diode-based" version but haven't focussed on it since I have plenty of signal transistors and what I have has worked Ok.
I took out the mechanical relay a while back and replaced it with the Si8752 and MOSFETS, using information and recommendations from Rod Elliot's articles, another thread here, and the application notes, and have been running it for a decent period of time with no issues. The amplifiers it is used with, use MOSFETS as outputs and are 50 - 100W rated output but I never crank them up as my old speakers have 93db sensitivity so they generate a lot of sound.
The circuit is, as i said, conventional and the mechanical relay is replaced by the 680R resistor and Si8752s and MOSFETS. It will run on amplifier supplies from 40 - 60V comfortably as the circuit has its own ~30V operating voltage via the linear regulator (MJE3055 + zener). The MJE3055 can be heatsinked if necessary. The board size is 68 x 85mm for a stereo setup and I have played around with different layouts to try to better match the amplifiers geometries and associated other components. When i get back to a PC on my network, i will try to find the board drawings.🙂
View attachment SpkrprotectwMOSFETs.pdf
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ASSR-V621-302E (surface mount type) is already an option (or you can short the DIP8 leads and then solder).
The dual-channel input/output is connected in series.
The dual-channel input/output is connected in series.
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I understand LKA, i just asking if you could consider full THT board because that is possible and some like me are not comfortable with SMD.
If it is not possible do you authorize me to design a PCB from you schematic with full THT.
If it is not possible do you authorize me to design a PCB from you schematic with full THT.
a well designd Amplifier no need additional speaker protection
BOM is very high for this circuit, to protect toys 50 to 100 W for living room,
you can handle 2500 W RMS with a simple crowbar to save speaker
If you have experience to design and service amplifier in KW Range Rails +/- 180 V DC
you wlll agree
BOM is very high for this circuit, to protect toys 50 to 100 W for living room,
you can handle 2500 W RMS with a simple crowbar to save speaker
If you have experience to design and service amplifier in KW Range Rails +/- 180 V DC
you wlll agree