EMC and power factor correction are not quite the same thing. Any item put on sale commercially in the EU has to have, among other things, reasonable EMC performance - unless you are Chinese in which case you just put a CE sticker on the back.
Power factor correction would only apply to higher power equipment, but I don't know where the threshold is. Someone on here is bound to know.
Power factor correction would only apply to higher power equipment, but I don't know where the threshold is. Someone on here is bound to know.
There are no limits for:
- Equipment with input power P ≤ 75 W.
- Professional equipment with input power P > 1 kW. *
- Symmetrical controlled heating elements with input power P ≤ 200 W.
- Independent dimming devices for light bulb
* Note: Professional equipment for use in trades, professions or industries and which is not intended for sale to
the general public. The designation shall be specified by the manufacturer
At present, power supplies (30W to 500W+) internal to class d guitar amplifiers use 50Hz mains transformers, folowed by a rectifier, then a large capacitor bank.
-therefore, they are obviously not power factor corrected.
Ao i am wondering , if such a power supply was replaced with an SMPS, would that need to be power factor corrected?
-therefore, they are obviously not power factor corrected.
Ao i am wondering , if such a power supply was replaced with an SMPS, would that need to be power factor corrected?
Hi, nigelwright7557 is correct, according to EN61000-3-2, class-A equipment (to which this would belong) needs low harmonic current emission (== good power factor) if rated power is > 75W. That includes audio equipment. So yes, a guitar amplifier with a 50Hz mains transformer and bridge rectifier and large caps (perfect recipe for producing a lot of current spikes) would need a filter at the input, or a active power factor correction circuit.
just my two cents
just my two cents
Hi,
This is getting very interesting indeed...because i can assure you that currently sold guitar amplifiers that are plugged into the mains, and are above 75W in power, are definetely not power factor corrected.
So howcome the authorities have not clamped down on the world of guitar amplifiers?
This is getting very interesting indeed...because i can assure you that currently sold guitar amplifiers that are plugged into the mains, and are above 75W in power, are definetely not power factor corrected.
So howcome the authorities have not clamped down on the world of guitar amplifiers?
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Are you asking about Power Factor Correction or EMC?
They are very different.
If your amplifier operates in Class D mode, it will generate lots of RF noise and EMC filtering is necessary.
Power Factor Correction should not be necessary for such a small amplifier.
The phase angles of the current vs. voltage (Power Factor) becomes important only when the input impedance of the power transformer is low and the transformer is drawing a lot of current from the mains. When that happens, Power Factor Correction capacitors or inductors can improve the efficiency of the power transfer into the transformer.
They are very different.
If your amplifier operates in Class D mode, it will generate lots of RF noise and EMC filtering is necessary.
Power Factor Correction should not be necessary for such a small amplifier.
The phase angles of the current vs. voltage (Power Factor) becomes important only when the input impedance of the power transformer is low and the transformer is drawing a lot of current from the mains. When that happens, Power Factor Correction capacitors or inductors can improve the efficiency of the power transfer into the transformer.
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