You are here

Log in or register to post comments
Freako
Freako's picture
Offline
Last seen: 1 year 7 months ago
Joined: Jan 17 2010 - 8:29am
Is this a lot of juice?

In the papers following my amplifier, it says that it is capable of 150Wpc i 8 Ohms, 230Wpc i 4 Ohms, but a mindblowing +/- 40 Amperes of peak current.

In my book this is pretty much, but knowing my amp very well (on year 4 now), I have no reason to not believe it. How much current is your amp capable of letting go, compared to the Wattage?

JSBach
JSBach's picture
Offline
Last seen: Never ago
Joined: Nov 28 2008 - 1:25am
Re: Is this a lot of juice?


Quote:
In the papers following my amplifier, it says that it is capable of 150Wpc i 8 Ohms, 230Wpc i 4 Ohms, but a mindblowing +/- 40 Amperes of peak current.

In my book this is pretty much, but knowing my amp very well (on year 4 now), I have no reason to not believe it. How much current is your amp capable of letting go, compared to the Wattage?


Damned if I know and I can't make any sense out of the Nu Force specifications on their web site http://www.nuforce.com/hi/products/Monoamp/ref9v3se/index.php
Don't care really as my ears tell me there's way more than enough power, either as current or watts, to run my Usher Be 10's. Mind you I never play music as rock concert levels and the sub bass is taken care of by the amps inside a pair of Velodyne DD15's and I'm not going hunting around for the power specs for those either.

Freako
Freako's picture
Offline
Last seen: 1 year 7 months ago
Joined: Jan 17 2010 - 8:29am
Re: Is this a lot of juice?

I was just curious

scarpi
scarpi's picture
Offline
Last seen: 5 years 11 months ago
Joined: Mar 22 2007 - 3:57pm
Re: Is this a lot of juice?

Wow, that sure is alot of amp draw. I thought my B&K amp drew alot of current at 17 amps. It has 200wpc into 8 ohms and 375wpc into 4 ohms. The best thing I did for it was have a dedicated 20 amp circuit installed for it.

Freako
Freako's picture
Offline
Last seen: 1 year 7 months ago
Joined: Jan 17 2010 - 8:29am
Re: Is this a lot of juice?

The 40 Amps is a peak thing, not continuously.

Freako
Freako's picture
Offline
Last seen: 1 year 7 months ago
Joined: Jan 17 2010 - 8:29am
Re: Is this a lot of juice?

I also guess it's not a very common thing, as my power fuse blows at 13 Amps, and it hasn't done that yet

Perhaps it's a capacitor thing?

scarpi
scarpi's picture
Offline
Last seen: 5 years 11 months ago
Joined: Mar 22 2007 - 3:57pm
Re: Is this a lot of juice?

Before I had the dedicated line installed, the amp always dimmed the living room lights or blew the circuit breaker when I turned it on. It seems to draw alot of current at turn on.

john curl
john curl's picture
Offline
Last seen: 11 years 10 months ago
Joined: Jan 20 2010 - 8:01am
Re: Is this a lot of juice?

Of course, it is PEAK meaning short term current. 40 amps is good. 10ms is all you need.

Jim Tavegia
Jim Tavegia's picture
Offline
Last seen: Never ago
Joined: Sep 1 2005 - 4:27pm
Re: Is this a lot of juice?

John verify my math:

The square root of watts/ohms = current. current X ohms = rms voltage. Peak voltage is current X ohms X 1.41?

I might be passing around misinformation.

Correct if I am wrong with great haste!

rvance
rvance's picture
Offline
Last seen: 9 years 3 months ago
Joined: Sep 8 2007 - 9:58am
Re: Is this a lot of juice?


Quote:
I also guess it's not a very common thing, as my power fuse blows at 13 Amps, and it hasn't done that yet

Perhaps it's a capacitor thing?

Capacitance is expressed in farads, whatever the hell those are.

RGibran
RGibran's picture
Offline
Last seen: 1 year 2 weeks ago
Joined: Oct 11 2005 - 5:50pm
Re: Is this a lot of juice?

Musical Fidelity A5 Integrated

400 watts @ 4 ohms

Current peak-to-peak = 75 amps

Jim Tavegia
Jim Tavegia's picture
Offline
Last seen: Never ago
Joined: Sep 1 2005 - 4:27pm
Re: Is this a lot of juice?


Quote:

Quote:
I also guess it's not a very common thing, as my power fuse blows at 13 Amps, and it hasn't done that yet

Perhaps it's a capacitor thing?

Capacitance is expressed in farads, whatever the hell those are.


-------------------------
On a QSC amp the current line current draw on a 260 watt/ch amp at 1/3 power with pink noise (about 90 watts per channel) is 6.6 amps per their website. I don't think I would want to be in the room to listen to that.

Freako
Freako's picture
Offline
Last seen: 1 year 7 months ago
Joined: Jan 17 2010 - 8:29am
Re: Is this a lot of juice?

I know, microFarads, actually.

Freako
Freako's picture
Offline
Last seen: 1 year 7 months ago
Joined: Jan 17 2010 - 8:29am
Re: Is this a lot of juice?

I found some kind of answer to my question:

scarpi
scarpi's picture
Offline
Last seen: 5 years 11 months ago
Joined: Mar 22 2007 - 3:57pm
Re: Is this a lot of juice?

I also found out that my B&K 200.5 amp has a spec of 75 amps peak to peak whatever that means.

Freako
Freako's picture
Offline
Last seen: 1 year 7 months ago
Joined: Jan 17 2010 - 8:29am
Re: Is this a lot of juice?

It means a LOT of juice!!!

bertdw
bertdw's picture
Offline
Last seen: 3 years 4 months ago
Joined: Sep 18 2007 - 5:41am
Re: Is this a lot of juice?


Quote:
I also found out that my B&K 200.5 amp has a spec of 75 amps peak to peak whatever that means.

Current flows in two directions, back and forth through the loudspeaker. Peak to peak refers to the difference between the positive peak and the negative peak. In your case, the amplifier will supply a maximum of 37.5 amps in each direction.

bertdw
bertdw's picture
Offline
Last seen: 3 years 4 months ago
Joined: Sep 18 2007 - 5:41am
Re: Is this a lot of juice?


Quote:
The square root of watts/ohms = current. current X ohms = rms voltage. Peak voltage is current X ohms X 1.41?

Your math is basically correct. I would only add that peak and rms need to be the same in each equation, so that:

rms current x resistance = rms voltage
peak current x resistance = peak voltage
peak voltage = rms current x resistance x 1.41 for a sinusoidal waveform

Music is rarely sinusoidal.

Jim Tavegia
Jim Tavegia's picture
Offline
Last seen: Never ago
Joined: Sep 1 2005 - 4:27pm
Re: Is this a lot of juice?

Much of that has to do with power supply design and cap storage. The NAD amps are a case in point, designed for large voltage swings for short periods.

bertdw
bertdw's picture
Offline
Last seen: 3 years 4 months ago
Joined: Sep 18 2007 - 5:41am
Re: Is this a lot of juice?

I don't understand your point. Yes, the NAD amps are designed to provide high peak outputs, but the formulas above remain the same.

Freako
Freako's picture
Offline
Last seen: 1 year 7 months ago
Joined: Jan 17 2010 - 8:29am
Re: Is this a lot of juice?


Quote:

Quote:
I also found out that my B&K 200.5 amp has a spec of 75 amps peak to peak whatever that means.

Current flows in two directions, back and forth through the loudspeaker. Peak to peak refers to the difference between the positive peak and the negative peak. In your case, the amplifier will supply a maximum of 37.5 amps in each direction.

Expressed as +/-37,5 A

bertdw
bertdw's picture
Offline
Last seen: 3 years 4 months ago
Joined: Sep 18 2007 - 5:41am
Re: Is this a lot of juice?

Yes, thanks. I tend to over-explain.

Freako
Freako's picture
Offline
Last seen: 1 year 7 months ago
Joined: Jan 17 2010 - 8:29am
Re: Is this a lot of juice?

Not really, I was just adding to your explanation, so no problem

JoeE SP9
JoeE SP9's picture
Offline
Last seen: 2 days 45 min ago
Joined: Oct 31 2005 - 6:02pm
Re: Is this a lot of juice?

The short term peak current output is dependent on the amount of capacitance in the power supply. A large energy storage capacity in the power supply can greatly increase short term peak power.
Amplifiers that have very large energy storage reserves will continue to have an output after AC power has been removed. The more storage the longer they will produce sound.

That energy storage is what allows some amplifiers to have very high peak current output.

Freako
Freako's picture
Offline
Last seen: 1 year 7 months ago
Joined: Jan 17 2010 - 8:29am
Re: Is this a lot of juice?

It may me checked if you pull the plug in the middle of playing a tune. The amp continues to play for several seconds without AC...

bertdw
bertdw's picture
Offline
Last seen: 3 years 4 months ago
Joined: Sep 18 2007 - 5:41am
Re: Is this a lot of juice?


Quote:
The short term peak current output is dependent on the amount of capacitance in the power supply. A large energy storage capacity in the power supply can greatly increase short term peak power.
Amplifiers that have very large energy storage reserves will continue to have an output after AC power has been removed. The more storage the longer they will produce sound.

That energy storage is what allows some amplifiers to have very high peak current output.

Hi Joe. I agree with everything you said. Not to be argumentative, but I'm now wondering if some people are misunderstanding my post about the formulas. I'm not saying that peak output currents can't be higher than 1.414 times the rms value, in fact they can be many times higher. Also, the formulas refer to the actual output, not the rated rms vs. the available peak output of an amplifier.

Is there something I said that you wish to dispute? That's fine, have at it! :-)

Jim Tavegia
Jim Tavegia's picture
Offline
Last seen: Never ago
Joined: Sep 1 2005 - 4:27pm
Re: Is this a lot of juice?

Since I posted them I did not say they did not.

JoeE SP9
JoeE SP9's picture
Offline
Last seen: 2 days 45 min ago
Joined: Oct 31 2005 - 6:02pm
Re: Is this a lot of juice?

Dispute you say!
I can't argue with math. I was an Electrical Engineer before I retired. I was only trying to point out that huge storage capacity in the power suply will allow short term peak current output well beyond an amplifiers rated output.

Elk
Elk's picture
Offline
Last seen: 2 years 2 months ago
Joined: Dec 26 2006 - 6:32am
Re: Is this a lot of juice?


Quote:
It may me checked if you pull the plug in the middle of playing a tune. The amp continues to play for several seconds without AC...


Pretty cool, yes?

Freako
Freako's picture
Offline
Last seen: 1 year 7 months ago
Joined: Jan 17 2010 - 8:29am
Re: Is this a lot of juice?

bertdw
bertdw's picture
Offline
Last seen: 3 years 4 months ago
Joined: Sep 18 2007 - 5:41am
Re: Is this a lot of juice?

It may be cool, but it might not be good for your speakers. After the power is disconnected the voltage on the power supply rails starts to decrease. When you begin to hear distortion, you're actually clipping the signal. We all know what clipping can do to your tweeters. I don't mean to alarm anyone, but please be careful.

Freako
Freako's picture
Offline
Last seen: 1 year 7 months ago
Joined: Jan 17 2010 - 8:29am
Re: Is this a lot of juice?

You are correct. This should never be done with the volume up high.

Elk
Elk's picture
Offline
Last seen: 2 years 2 months ago
Joined: Dec 26 2006 - 6:32am
Re: Is this a lot of juice?

Yes, an excellent point.

bertdw
bertdw's picture
Offline
Last seen: 3 years 4 months ago
Joined: Sep 18 2007 - 5:41am
Re: Is this a lot of juice?

I didn't think you guys would pull the plug at full blast, but just because I'm paranoid doesn't mean everybody's not against me.

Freako
Freako's picture
Offline
Last seen: 1 year 7 months ago
Joined: Jan 17 2010 - 8:29am
Re: Is this a lot of juice?

Thanks for caring for our speakers

  • X