I bought one of those smps power supplies to drive my own stereo class A/B amplifier rated at approximately 250 watts/channel at 8 ohms. This amp needs +/- 70 volts but the smps output of +/- 65 is also good enough. The output power would drop a bit but that is not a concern at all.
I do not quite know the sudden transient response of SMPS supplies so do you think it would be better to also supplement this with additional 50k or 100k uF of reservoir capacitors at its output ? I have 4 x 50k uF 100 volt capacitors at my disposal already so there would be no additional cost.
This SMPS has an inrush current of about 37 amps or so, without any capacitors at its output, which is extremely high indeed. Together with the capacitors attached, I am sure it would not be very happy at all at power on. To this end, I am also putting a relay bypassed power resistor (wirewound chassis type 33 ohm, 150/200 watt) current limiter at the mains input, limiting the initial current to about 4 amps (at 120 volts AC) for the first 3-4 seconds.
Given all the above, does anyone see any issues apart from the 3-4 second warming up of the current limiter resistor which will be bypassed in about 4 seconds max ?
In addition, would it be wiser and/or preferable to use a PTC thermistor (yes postive TC) instead of the resistor to limit the current permanently in case the bypassing relay does not operate and engage ? This would limit the current passing and a PTC would eventually stop the current to a negligible amount, so nothing destroyed.
Thanks
I do not quite know the sudden transient response of SMPS supplies so do you think it would be better to also supplement this with additional 50k or 100k uF of reservoir capacitors at its output ? I have 4 x 50k uF 100 volt capacitors at my disposal already so there would be no additional cost.
This SMPS has an inrush current of about 37 amps or so, without any capacitors at its output, which is extremely high indeed. Together with the capacitors attached, I am sure it would not be very happy at all at power on. To this end, I am also putting a relay bypassed power resistor (wirewound chassis type 33 ohm, 150/200 watt) current limiter at the mains input, limiting the initial current to about 4 amps (at 120 volts AC) for the first 3-4 seconds.
Given all the above, does anyone see any issues apart from the 3-4 second warming up of the current limiter resistor which will be bypassed in about 4 seconds max ?
In addition, would it be wiser and/or preferable to use a PTC thermistor (yes postive TC) instead of the resistor to limit the current permanently in case the bypassing relay does not operate and engage ? This would limit the current passing and a PTC would eventually stop the current to a negligible amount, so nothing destroyed.
Thanks
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With SMPS you need very little smoothing in your amp, just a little locally.
SMPS can be touchy about power on surge and will cut out if its too high.
Depends a lot on the power of SMPS.
Yours is pretty heft so should be able to stand some smoothing at the amp but I cant say exactly how much.
I would start off smal land work your way up and see where it starts to drop out then back off a bit.
SMPS can be touchy about power on surge and will cut out if its too high.
Depends a lot on the power of SMPS.
Yours is pretty heft so should be able to stand some smoothing at the amp but I cant say exactly how much.
I would start off smal land work your way up and see where it starts to drop out then back off a bit.