Hi,
I wrote to Hypex to determine the maximum capacitance that can be applied to the output of the Hypex SMPS400A400 power supply to reduce bus pumping. Their response was that :
"It is unsupported to apply extra capacitance on the output of the supply. The surge current could damage the supply."
Has anyone any experience of using reservoir capacitors on their SMPS units - (63volt units) ?
Of course there will be local reservoir capacitance as per the class D amplifier, so the blanket statement that it is not supported seems overly cautious.
Thanks and regards for any feedback on this.
Regards,
Shadders.
I wrote to Hypex to determine the maximum capacitance that can be applied to the output of the Hypex SMPS400A400 power supply to reduce bus pumping. Their response was that :
"It is unsupported to apply extra capacitance on the output of the supply. The surge current could damage the supply."
Has anyone any experience of using reservoir capacitors on their SMPS units - (63volt units) ?
Of course there will be local reservoir capacitance as per the class D amplifier, so the blanket statement that it is not supported seems overly cautious.
Thanks and regards for any feedback on this.
Regards,
Shadders.
Hi,
From :
Avoid Overvoltage Stresses by Minimizing | Maxim Integrated
A strange phenomenon can occur with Class D audio amplifiers that have single-ended output loads: the power-supply voltage increases as power is delivered to the load. The phenomenon is known as power-supply "pumping,"
Regards,
Shadders.
From :
Avoid Overvoltage Stresses by Minimizing | Maxim Integrated
A strange phenomenon can occur with Class D audio amplifiers that have single-ended output loads: the power-supply voltage increases as power is delivered to the load. The phenomenon is known as power-supply "pumping,"
Regards,
Shadders.
Hi,
It does not matter what the amplifiers are - they are class D, and the single SMPS will power 3 class D amplifiers (single ended operation) which are driving the bass, mid and tweeter of a single speaker.
Regards,
Shadders.
It does not matter what the amplifiers are - they are class D, and the single SMPS will power 3 class D amplifiers (single ended operation) which are driving the bass, mid and tweeter of a single speaker.
Regards,
Shadders.
I guess it does matters, not the brand but their combined power consumption, since the SMPS only can deliver enough juice to drive a total of 400 Watts@ 20 Hz, according to their specs.
Kind regards,
Willem.
Kind regards,
Willem.
Hi,
I will not be using the system at such levels where it will regularly exceed 400watts. Should there be a transient which does not exceed 400watts, yet can still cause "some" bus pumping, then my preference is to counter this with reservoir capacitance. Something is better than nothing.
Regards,
Shadders.
I will not be using the system at such levels where it will regularly exceed 400watts. Should there be a transient which does not exceed 400watts, yet can still cause "some" bus pumping, then my preference is to counter this with reservoir capacitance. Something is better than nothing.
Regards,
Shadders.
Hi @Amplifier Dude,
Thanks - is this essentially the power supply Mosfet clamps the voltage rail ?
Thanks and regards,
Shadders.
Thanks - is this essentially the power supply Mosfet clamps the voltage rail ?
Thanks and regards,
Shadders.
These supplies are designed to power single ended class D amps. (Like all the Hypex amplifiers). Because the supply was designed this way, they designed it to tolerate supply pumping. And they did so by using mosfets that can sink current, rather than a rectifier like most supplies use. So adding caps will only worsen the supply quality, and potentially damage it like the Hypex engineer told you.
Hi @Amplifier dude,
Thanks. The Hypex support indicated that it would have been the surge current that was the issue. They did not mention anything about bus pumping in the e-mail i received.
Thanks and regards,
Shadders.
Thanks. The Hypex support indicated that it would have been the surge current that was the issue. They did not mention anything about bus pumping in the e-mail i received.
Thanks and regards,
Shadders.
Well maybe everyone there isn’t a power supply expert. They hired a 3rd party engineer to design them 12-14 years ago.
Years ago when I had my SDS-250 class d amp with ConnexElectronic 300W smps, experienced bus pumping problem when play punch and deep bass, it just stopped playing. Later I changed to linear PS with 600VA 35V transformer and about 80000 u caps, it's much much better.
Yeah because the Connex supplies can’t deal with supply pumping. Others experienced the same problem with those supplies and the Purifi amps.
I believe that's the difference between linear and smps, for example a 2X100w amp, a 300VA transformer and some big caps will work just fine, but if use smps, at least need one rated 600w, maybe even more
Or just a SMPS that is properly engineered for the application. The 400w UCD 400 single ended class D amp works perfectly fine with the 400W SMPS400A400.
