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Hypex FA501 rms output vs other class D amps

Palmspar

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Dec 31, 2023
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I use the Hypex FA501 to power my DIY dual opposed subwoofer, it works fine and sounds verry good.
But it seems that the 500w from the Hypex is peak power, not rms.
The 500 watt peak output @4ohm looks not much compared to a SVS SB2000 subwoofer that has 500w rms and 1150w peak output.
In my old car i used a JL Audio class d amp that also had 500w rms @ 2 ohm with a test tone @50hz.
The Hypex looks well bould it seems strange that it has less power then other class D amps.
 
But it seems that the 500w from the Hypex is peak power, not rms.
Screenshot_20240317-150452_Chrome~2.png
 
An amplifier with a solid well-regulated power supply and good thermal design will put-out the same power on short-term peaks or continuously. Otherwise,, the power supply voltage can "sag" or it can go into thermal protection with continuous tones and the power will drop compared to the short-term peak.

It's not related to amplifier class.

The problem with "peak power" is that there is no standard measurement method. It might put-out peak power for 1 millisecond or 1 second, etc.

Headroom for occasional peaks can be a good thing and if there was a peak-power standard it could potentially be useful since music isn't continuous full-power tones, but without a standard it's usually it's best to ignore peak power ratings.

Plus, most manufacturer's specs are dishonest to some extent so you need independent measurements. I don't think anybody disassembles powered subs to measure the amplifier inside.
 
Thanks, i read the specs a time ago from the NC500 oem wat has 100w rms and 700w peak @4 ohm.
And concluded the specs from the FA501 must be also also peak output.
 
Looking at most subwoofers, they A) write optimistic numbers, B) have very insensitive drivers or C) have a more powerful amp than they need. Or possibly a combination.
 
Looking at most subwoofers, they A) write optimistic numbers, B) have very insensitive drivers or C) have a more powerful amp than they need. Or possibly a combination.
When i read the review of your Sigberg 10D subwoofer on audioholics 1.5 year ago, it seems indeed strange to see a subwoofer with 500w amp performing so good.
Its very wel bould with great components to have that level of performence.
 
When i read the review of your Sigberg 10D subwoofer on audioholics 1.5 year ago, it seems indeed strange to see a subwoofer with 500w amp performing so good.
Its very wel bould with great components to have that level of performence.

In reality knowing the amp power gives you almost no information without understanding the driver and system sensitivity. 500W is more than enough for the 10D.
 
Hypex 501, which has 500W, requires, for example, 50V DC from the power supply. Old-style power supplies need a 35.5V RMS transformer that charges the capacitors to a peak voltage of 50V. This is exactly +3dB. So we have 3dB of Energy in the Capacitors. If the capacitors are too small, they will be discharged and the voltage will drop to 35V, which will cause a power drop of -3dB, the amplifier will clip and destroy the tweeters. The situation is better if we have modern switching power supplies that hold the voltage until they reach the limit of their capabilities. Maybe the Hypex power supply is well made and its amplifier is not able to overload it, and then the max power and RMS are the same.​
 
I hate to be pedantic, but there is actually no such thing as RMS power - it's just average or continuous power. RMS is only used for current and voltage.
 
An amplifier with a solid well-regulated power supply and good thermal design will put-out the same power on short-term peaks or continuously. Otherwise,, the power supply voltage can "sag" or it can go into thermal protection with continuous tones and the power will drop compared to the short-term peak.

It's not related to amplifier class.
This needs more clarification and micro-detailing per say. What I really like about switch mode/PWM power supplies operating with class D amplification is the technology that enables the operation to reduce the power available to the audio amp section to protect the overall system. Class A/AB do not do this because of the use of a linear power supply.
 
I hate to be pedantic, but there is actually no such thing as RMS power - it's just average or continuous power. RMS is only used for current and voltage.
I am aware of this and respect that. The thing for me is the RMS value is so commonly applied that it has become a useful value.
 
At page 5 the document says 100w continuous output power?
Thats exact the reason i make this topic.

This has been discussed to death countless times on this forum. Amir's tests of various amps have shown time and time again that the Hypex modules does achieve or exceed the rated powers at 8/4/2 ohm.
 
The 700W@4ohm for the Hypex amplifier is peak power; continuous output power is 100W.
Maybe this puts things in perspective?
The countinous output means constant sinus wave output and the limit is thermally related.
Do you listens to sinus waves countinously? ;)

Above is a discusion on diyaudio forum, it make more sense to me now.
I read and post on forums to learn more, therfore startend this topic.
 
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When i read the review of your Sigberg 10D subwoofer on audioholics 1.5 year ago, it seems indeed strange to see a subwoofer with 500w amp performing so good.
Its very wel bould with great components to have that level of performence.
An amps power output doesn't necessarily make a better sub compared to one with lower output, FWIW.
 
Advertising of watts on a sub with no other details certainly has created some odd impressions on how meaningful it is....
 
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