1 - 20 of 31 Posts

#### Joeslacker

·
##### Registered
Joined
·
15 Posts
Discussion Starter · ·
Hello It's me again. I'm using a Fully Regulated Low Ripple Dc Switching Power Supply (pyramid psv300). And I would like to know how many watts it can handle total? I've used a calculator on the net but I'm not sure if I should go by the 13.8 volts that it describes or the AC amount of 110-120? I guess it would be about 440 watts or so for the 13.8 which seems kinda pathetic to me and I doubt it I've seen people on the net have multiple amps hooked up to just one of these power supplies.

I'm going to have about 210 watts true power from my amp to each channel (4 channel amp to 2 speakers so 2 channels) so would I add the power from all 4 channels or just the two since I'm using only 2 channels to power something. Also would it be just the amount of per channel say 210 watts or would I add up the two channels total PLUS the watts from the sub amp (300 watts 1 channel 2 10 inch kenwood kfc x100 subs).

So I'm looking at I THINK around 720 watts. Would this work on this power supply? Thanks guys!

#### Mike-G

·
##### Registered
Joined
·
203 Posts
Ohm's Law: P=VxI; Output is 13.8V x 30A = 414 Watts Max or 292.7 W Rms

This would be fine for testing at low volume levels, but not at full tilt.

#### Joeslacker

·
##### Registered
Joined
·
15 Posts
Discussion Starter · ·
Ohm's Law: P=VxI; Output is 13.8V x 30A = 414 Watts Max or 292.7 W Rms

This would be fine for testing at low volume levels, but not at full tilt.
I'm having a hard time understanding this. If it was 292.7 watts rms then how come I'm running 22 watt head unit with 300 watt sub? I've seen people with mondo setups with just one of these things..

Thanks for the reply although I'm having a hard time believing this.

#### Mike-G

·
##### Registered
Joined
·
203 Posts
That 300W does not occur all the time, only when the amp is pushed hard. At normal volume levels, the power output is much less.

#### Joeslacker

·
##### Registered
Joined
·
15 Posts
Discussion Starter · ·
That 300W does not occur all the time, only when the amp is pushed hard. At normal volume levels, the power output is much less.
How much less are we talking? I don't think we really answered my question anyway would the power supply I'm using now supply the power needed for that 210 watt x2 channel amp on top of the 300 that I'm using for the subs? Or would I have to get one of greater amperage if so how much greater say 60 amps?

#### Mike-G

·
##### Registered
Joined
·
203 Posts
What are you using the power supply for exactly? The amount of power output is probably non-linear, so the output depends on the volume level.

#### Mike-G

·
##### Registered
Joined
·
203 Posts
You would need to get a clamp ammeter and see what kind of current is being pulled as you turn the volume up and work through the values.

#### Joeslacker

·
##### Registered
Joined
·
15 Posts
Discussion Starter · ·
What are you using the power supply for exactly? The amount of power output is probably non-linear, so the output depends on the volume level.
If it depends on the volume level then with the 210 watts to each speaker I would assume I'd be using less than 1/3rd volume so It shouldn't be a problem. But yeah with the clamp ammeter seems really pricey.

#### dumdum

·
##### Registered
Joined
·
2,369 Posts
You’d be better off buying a couple of small mono amps from eBay that run off mains if you’re only running 1/3 volume as that will probably be sub 50 watts and less on music, half volume on a stereo doesn’t equal half power or half as loud, more like 1/8 or less most likely

But as said the only way is to measure it and check to be 100% accurate

#### Grinder

·
##### Registered
Joined
·
3,951 Posts
Hello It's me again. I'm using a Fully Regulated Low Ripple Dc Switching Power Supply (pyramid psv300). And I would like to know how many watts it can handle total? I've used a calculator on the net but I'm not sure if I should go by the 13.8 volts that it describes or the AC amount of 110-120? I guess it would be about 440 watts or so for the 13.8 which seems kinda pathetic to me and I doubt it I've seen people on the net have multiple amps hooked up to just one of these power supplies.

I'm going to have about 210 watts true power from my amp to each channel (4 channel amp to 2 speakers so 2 channels) so would I add the power from all 4 channels or just the two since I'm using only 2 channels to power something. Also would it be just the amount of per channel say 210 watts or would I add up the two channels total PLUS the watts from the sub amp (300 watts 1 channel 2 10 inch kenwood kfc x100 subs).

So I'm looking at I THINK around 720 watts. Would this work on this power supply? Thanks guys!
It would help to know the make and model of your amplifier, speakers and subwoofers.

Absent adequate testing and measurement, one cannot know for sure how many watts your power supply can deliver; nor how many watts your amp will draw at maximum (or at any specific volume). We can say for sure that an amplifier is not 100% efficient, and that a speaker can only draw as much power as it is given.

Bear in mind that the vast majority of power requirement is at elevated levels. For example, an increase in volume of 10 dB (approximately twice as loud) will require ten times the power (in terms of amplifier output. Based on amplifier efficiency, power supply output requirement might be even greater than 10x).
For more on this: https://jlaudio.zendesk.com/hc/en-us/articles/217201737-Doubling-Power-vs-Doubling-Output

Be sure to heck out this excellent site as well: Basic Car Audio Electronics

Just hook it up and try it. Install a 20 amp fuse on the positive power cable (between the power supply and amplifier), and see how it goes. Chances are, you'll be quite surprised how loud it can get. If you want it much louder than that, you'll need a lot more power supply (and amplifier?) capacity.

#### Rrrrolla

·
##### Registered
Joined
·
389 Posts
The power supply inside the amp matters in this situation. An amp can output 1000w for a very short time and not require 1000w of input power. This is because amplifiers have capacitors on their input DC side as well as on the rails (the voltages made by the internal power supply). The extent of which this regulation exists varies from amp to amp. So as long as you're not playing test tones for log periods of time, the power output from an amp connected to a 30A power supply can be much MUCH higher than what you would calculate from the old Pout = Pin X Eff% formula.

#### Joeslacker

·
##### Registered
Joined
·
15 Posts
Discussion Starter · ·
You’d be better off buying a couple of small mono amps from eBay that run off mains if you’re only running 1/3 volume as that will probably be sub 50 watts and less on music, half volume on a stereo doesn’t equal half power or half as loud, more like 1/8 or less most likely

But as said the only way is to measure it and check to be 100% accurate
Well I was just assuming 1/3rd volume since the speakers are 94 db sensitivity and I'm putting 210 watts to them. So you're saying that 1/8th of the power being put to the speakers is actually being used hence about 50 watts or so used on music. If this is the case then It should be acceptable to use on this particular power supply unless the max total rms from the speakers and sub amp would be greater than that of the max of the power supply so about 410 watts and it's about 322 watts now so that's good now but if I upgrade to 210 watts each speaker (x2speakers) then the max from the power supply would have to be greater than say 700 so I would need aproximately a 60 amp power supply?

Reply to Grinder @Grinder as to what my make model of my amp speakers and subwoofers.

I'm running Two kenwood excelon KFC - xw100 10 inch subwoofers, With a Kenwood Excelon X500-1 powering those subs I'm using a Kenwood Excelon kdc - x303 head unit. I'm using Polk Audio MM692 - MM1 Series 6x9" Coaxial Speakers and I'll be using a NVX VAD10004 power amp for the speakers.

@Rrrrolla
So you're saying that as long as I'm not playing those test tones I'm going to be fine with the equipment I stated for that power supply?

#### JCsAudio

·
##### Registered
Joined
·
2,779 Posts
If you put a 12 volt car battery in parallel with the power supply than you will increase the power supplies ability to handle temporary musical demands greatly. If your speakers are 94% efficient, meaning they produce 94 db with just one watt and you’re listening to music at adult listening levels than your amplifiers aren’t using much power at all playing music through those speakers. The subwoofer amplifier will be the one that demands the most but even then at normal listening levels it may be fine especially if you have a car battery in the equation. If it’s a sealed box it will use more power than say a ported box for the same volume.

#### Holmz

·
Joined
·
6,691 Posts
It would help to know the make and model of your amplifier, speakers and subwoofers.
...
It would help more to have an SPL reading.

Unless one has some digitised sampling, then just using the RMS SPL power is a great way to work out RMS wattage.

250W if you play a DC tone (nobody does this) on a class D amp.
500 W with any music.
How on earth did you come up with ^this^?

·
Joined
·
3,951 Posts

#### Attachments

• 10.4 KB Views: 111

#### Holmz

·
Joined
·
6,691 Posts
^Maybe^

It is a microwatt output power with the volume down, and with a class-AB maybe 30W input power for that micro watt of output???

A class-D may be lower input power.

However if it is cranked up, then unless we know what "cranked up" is, we have no way of knowing how much of the hundreds of watts are being used.maybe 10-20watts???

But with an SPL measurement then we know exactly what "cranked up" means, and would be close to knowing exact output watts using some simple maths.

Ohm's Law: P=VxI; Output is 13.8V x 30A = 414 Watts Max or 292.7 W Rms

This would be fine for testing at low volume levels, but not at full tilt.
I thought 300W RMS would be "super loud" if one is not considering a sub channel.

A 30 amp supply running into a battery would be a sensible approach.

#### Grinder

·
##### Registered
Joined
·
3,951 Posts
^Maybe^

It is a microwatt output power with the volume down, and with a class-AB maybe 30W input power for that micro watt of output???

A class-D may be lower input power.

However if it is cranked up, then unless we know what "cranked up" is, we have no way of knowing how much of the hundreds of watts are being used.maybe 10-20watts???

But with an SPL measurement then we know exactly what "cranked up" means, and would be close to knowing exact output watts using some simple maths.
It's called sarcasm...

I know perfectly well what you were on about. Not sure why you felt the need to quote my post with your "it would help more to..." impertinence.

#### JCsAudio

·
##### Registered
Joined
·
2,779 Posts
Fight, fight, fight.

·