M2X amp uses optocoupler to control output stage bias. The circuit looks very safe in cause of failure. In most cases the bias will just drop to zero and = zero voltage at output. I am building a set of M2X mono blocks in the moment and no issues so far.
Has anybody used DC blocking cap in a dual rail amp, where it takes too long for offset voltage to stabilize, starting from a high DC voltage at power on and has a similar DC voltage at power off?
When I powered up M2X for first time I measured DC offset and it stayed far below 1 V and that was before I adjusted DC offset. At power down the PSU is at zero in a few seconds (even with large capacitors) caused by the relative large bias current. So power down is no problem (I won't call it DC at power down but a low frequency AC). I don't even think you will hear a "blob" sound....but will see when I connect speakers.
Which speaker system do you have?
I assume that it is only the woofer which is DC exposed?
That would be the normal case with a passive crossover.
I assume that it is only the woofer which is DC exposed?
That would be the normal case with a passive crossover.
Hi,
If you were asking me,
At present its a Monitor Audio BX6 for now so not sure if its just woofer
Thankyou
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If your'e using a cap or transformer at the output, DC protection may be nearly useless in your case..
You'll need to intuit some of the features of my scheme and how to apply it to your own liking.. This scheme assumes that you are using a 5v source, separate from the amp supply. My system is entirely controlled using a Raspberry Pi and makes use of controlling the mains AC power itself. If you were to use something like this, you could have a similar setup except you could control the power manually by putting a switch between the latching relay and a mains 5v relay. Once the system is triggered, you will need to reset the relay by simply reversing the polarity momentarily. Hopefully that will never happen, however, this is a great way to keep from starting a fire in your house or potentially damaging your speakers. You can disregard the "service" label in the image in that it is just for sense, application using with the Pi.
You'll need to intuit some of the features of my scheme and how to apply it to your own liking.. This scheme assumes that you are using a 5v source, separate from the amp supply. My system is entirely controlled using a Raspberry Pi and makes use of controlling the mains AC power itself. If you were to use something like this, you could have a similar setup except you could control the power manually by putting a switch between the latching relay and a mains 5v relay. Once the system is triggered, you will need to reset the relay by simply reversing the polarity momentarily. Hopefully that will never happen, however, this is a great way to keep from starting a fire in your house or potentially damaging your speakers. You can disregard the "service" label in the image in that it is just for sense, application using with the Pi.
They call them 2 1/2 way which probably means that both 2 x bass driver and mid-bass driver plays bass so 3 x 6 1/2" will get DC:
BX6
…..so power from eventually DC are spilt between 3 voice coils…..so it has to be a serious error to blow all 3 drivers voice coils.
Maybe a simple solution could be an old fashion fuse.....like 1.5 A or 2A F types....I am quite sure such a fuse would burn before voice coils gets too hot to melt wire insulation and glue.
BX6
…..so power from eventually DC are spilt between 3 voice coils…..so it has to be a serious error to blow all 3 drivers voice coils.
Maybe a simple solution could be an old fashion fuse.....like 1.5 A or 2A F types....I am quite sure such a fuse would burn before voice coils gets too hot to melt wire insulation and glue.
Thankyou everyone.
I have parked the idea of using caps at output.
I am planning to use Nigel's dc protection circuit.
I have parked the idea of using caps at output.
I am planning to use Nigel's dc protection circuit.
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95% of failures will happen in the first hour, so don't hook up a speaker
until you've gotten well past that.
until you've gotten well past that.
Helo,guys ! How can I control DC offset of STK 403 , I have an Yamaha-rx-v357 and all STK have 1 V DC offset on output, otherwise sound is clear if protection is deactivated...
I've found on Google : "I found that the +/- Pre voltages were very important in setting the DC offset on the output."
I've found on Google : "I found that the +/- Pre voltages were very important in setting the DC offset on the output."
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better try in Solid State forum : https://www.diyaudio.com/forums/solid-state/
guys playing around are less likely to have extensive experience with STK circuits
in any case - best way is to prepare and post schematic of amp in question, how you posted it here, there is not enough info
guys playing around are less likely to have extensive experience with STK circuits
in any case - best way is to prepare and post schematic of amp in question, how you posted it here, there is not enough info