AMPS: High Power Vs High Current?

[highfigh]

I would caution trying to calculate output power into a loudspeaker using Ohms law. Most loudspeakers are not resistors they are reactive and can load an amplifier with a unique, inductive output. Some loudspeakers like the MagnaPlanars are mostly resistive, but we have measured component amplifiers that can output 125 watts into a Dale resistor load (8 ohms) but into a certain loudspeaker the power output drops to 22 watts...

A far more accurate method is to use the PowerCube, unfortunately few testing labs take the time to do this.

Just my $0.02...

Rockford-Fosgate used that and it made most other amplifiers look like crap.

 

[highfigh]

Interesting......but what is PowerCube? I am almost afraid to ask......LOL!!!! Thanks!


Cheers,

Phil

Easier to google than to explain.

http://audiograph.se/

And look at the skinny wire they use!

 

[Hetfield]

Wish you lived closer. I'd have you over for a listen. Wouldn't mind hearing yours either.

Yeah we could contrast and compare the Def Techs and Ultras. That would be fun. I'd love to hear the PSA MT-110s too. I was almost ready to scrap my whole system I just built for PSA speakers because of everything I read about them. I would have been in big trouble at home if I did that. Then I came home from work early one day and watched The divergent: Allegiant and really listened to what I have. I cranked it up to -25 which is cranking it to me and I ended up saying out loud, "I'd have to be brain dead to trade these out for anything". I mean it sounded so good there was no was I could justify making any type of move. I was stupid close though. This dam hobby is dangerous! We've all been there.

Sent from my Pixel using Tapatalk

 

[speakerman39]

Easier to google than to explain.

http://audiograph.se/

And look at the skinny wire they use!

You beat me to it as I was getting ready to google PowerCube.........LOL!!!! Got a lot going on this morning. Thanks!


Cheers,

Phil

 

[KEW]

No, I have not. But, honestly I do not know how to read them very well. My eyesight is not the greatest being diabetic. Care to interpret it for me? Or, explain to me how to read the impedance curves better? Might as well learn something new here I always say.

Cheers,

Phil

I'm not the one to interpret it, and I think it is important to also have a phase chart (most testers put impedance and phase on the same chart). But here is the impedance graph.

As an aside: Almost not sure why they'd bother to take measurements if they are going to scale the vertical axis so high that you cannot read it very well. 15 or 20 Ohms would be much more appropriate.

It looks like it is right around 4 ohms for much of its frequency response, but does not drop to lower values. To me (with my limited understanding) that means it should do fine with a solid mid-level AVR unless you are going to drive it hard.

As far as trying to get "warmer" sound out of your Dentons, I would say you are much more likely to get the sound you want by switching speakers than doing some sort of trial and error attempt with amps.
For an amp to warm up the sound means it adds distortion to the mix. I would stick with the AVR amp or buy a clean amp that does not color the sound instead of looking for one that has some built-in distortion (which, to me, reads "poorly engineered") that matches the sound signature.

A miniDSP is probably the best way if you want to "custom tweak" you sound.

 

[AcuDefTechGuy]

Yes, so very true. But, sometimes we also used some simplified calculus as well. But, once I go into Calculus II, things became much more difficult for me. It was a nightmare to say the least......LOL!!!! Glad that is over with and done!

Cheers,

Phil

I aced Calculus III and Engineering Mathematics I, but I can't remember anything now to save my life.

These days there is an app for everything.

Back then using Calculators was a big thing. Now we don't even use calculators. Just use apps on phones.

 

[PENG]

I would caution trying to calculate output power into a loudspeaker using Ohms law. Most loudspeakers are not resistors they are reactive and can load an amplifier with a unique, inductive output. Some loudspeakers like the MagnaPlanars are mostly resistive, but we have measured component amplifiers that can output 125 watts into a Dale resistor load (8 ohms) but into a certain loudspeaker the power output drops to 22 watts...

A far more accurate method is to use the PowerCube, unfortunately few testing labs take the time to do this.

Just my $0.02...

Agree caution is needed, but Ohm's law and the power formula are applicable regardless. The ACD drop to 35W from 100W 2 channel is due to impedance dips and/or the unit's protective cct design for the specific model, not the nature of the impedance, not directly anyway.

Highly reactive loads still follow the power formula and Ohm's law but it would result in lots of heat dissipated in the amp instead of the load. Steve wrote an article for AH a few years ago that explained this quite well.

 

[AcuDefTechGuy]

Agree caution is needed, but Ohm's law and the power formula are applicable regardless. The ACD drop to 35W from 100W 2 channel is due to impedance dips and/or the unit's protective cct design for the specific model, not the nature of the impedance, not directly anyway.

Highly reactive loads still follow the power formula and Ohm's law but it would result in lots of heat dissipated in the amp instead of the load. Steve wrote an article for AH a few years ago that explained this quite well.

So what's the bottom line as far as "High Current Amp vs High Power Amp" ?

Power = Voltage x Current

so High Current is High Power (and High Voltage).

 

[Hetfield]

Pretty funny this subject because my amp is the HCA 1205A amp which stands for high current amp I believe. What that actually means or what that does is way above my pay grade but that is what that means it now Parasound model number.

Sent from my Pixel using Tapatalk

 

[PENG]

Just a friendly reminder, everyone knows Ohm's so please remember it is just V=IR for a resistive load, and V=IZ for a reactive load.

Z is a phasor, or incorrectly called, vector, that has the magnitude and phase components.

To calculate power, you can use the power formula P = V x I x Cosine of the phase angle between V and I (the voltage and current phasor)

For a resistive load, the phase angle is virtually 0, and cosine 0 degree is 1

For a reactive load such as the impedance of a loudspeaker, the phase angle can be as high as 60 degree, and cosine 60 degrees = 0.5 so you can do the math and figure out how much watts would end up in the amp instead of the speakers.

You can also see that the phase angle does not factor into the current (I) calculation using Ohm's law, but it obviously affect the power calculations.

ADTG: I hope you aced in trigonometry too.

 

[Pogre]

Showoff...

 

[AcuDefTechGuy]

ADTG: I hope you aced in trigonometry too.

I aced Trigonometry and Analytic Geometry too, but that was 25 years ago when I actually worked part time as a Math Tutor.

Ah, the good old days when I felt a lot smarter.

 

[AcuDefTechGuy]

Showoff...

Nah, that ain't nothing.

He's going to be showing off in his next post when he talks about E=MC^2 and Einstein's Theory of Relativity as it pertains to loudspeakers, power, gravity and all that physics crap.

 

[mtrycrafts]

I thought the 10v was just a random example. Just checking to make sure. Have not done this kind of math in a very long time.....LOL!!! None of it is really that hard, but I know it can easily get that way fast and in a hurry. I got an A in college Calculus I, but Calculus II was an entirely different story..........LOL!!!! Thanks!


Cheers,

Phil

Well, not to worry, no calculus involved in Ohm's law, just a simple formula: E=IxR; P=IxE

Yes, that 10 V was random and a nice round number.
Reading some old issues of The Audio Critic that used the power cubed approach to amp testing, it seems that many if not most of those amps had at least 30V rail into 8 Ohms, some higher of course.

So, just play with that power and see what it can deliver. Just don't forget, that high current comes with a higher rail voltage; it has to. And more power, hand in hand. It is the law.

 

[mtrycrafts]

Interesting......but what is PowerCube? I am almost afraid to ask......LOL!!!! Thanks!


Cheers,

Phil

You should never be afraid to ask. As posted by the link, it is just adding inductive and capacitive loads to the amp. Still, power, voltage, current are all interlinked. If you don't intend to switch speakers to be an easier load, then that remains constant in your test calculations for power and current. But as the graph in that link shows, amps will sag in rail voltage as load decreases.

 

[mtrycrafts]

...
And look at the skinny wire they use!

Yes, but how much current through them?
And, may not be continuous power.

 

[mtrycrafts]

I aced Calculus III and Engineering Mathematics I, but I can't remember anything now to save my life.

These days there is an app for everything.

Back then using Calculators was a big thing. Now we don't even use calculators. Just use apps on phones.

And, when the power goes out, battery runs down? Work stands still.
Bring back the slide ruler. But wait, that needs Google to learn how to use. LOL.

 

[AcuDefTechGuy]

And, when the power goes out, battery runs down? Work stands still.
Bring back the slide ruler. But wait, that needs Google to learn how to use. LOL.

Oh no, when phone batteries run down, we use those little portable battery chargers.

 

[mtrycrafts]

So what's the bottom line as far as "High Current Amp vs High Power Amp" ?

Power = Voltage x Current

so High Current is High Power.

Oh, but that current didn't exist without that higher voltage. One is not without the other, hand in hand, inseparable.

 

[speakerman39]

I'm not the one to interpret it, and I think it is important to also have a phase chart (most testers put impedance and phase on the same chart). But here is the impedance graph.

As an aside: Almost not sure why they'd bother to take measurements if they are going to scale the vertical axis so high that you cannot read it very well. 15 or 20 Ohms would be much more appropriate.

It looks like it is right around 4 ohms for much of its frequency response, but does not drop to lower values. To me (with my limited understanding) that means it should do fine with a solid mid-level AVR unless you are going to drive it hard.

As far as trying to get "warmer" sound out of your Dentons, I would say you are much more likely to get the sound you want by switching speakers than doing some sort of trial and error attempt with amps.
For an amp to warm up the sound means it adds distortion to the mix. I would stick with the AVR amp or buy a clean amp that does not color the sound instead of looking for one that has some built-in distortion (which, to me, reads "poorly engineered") that matches the sound signature.

A miniDSP is probably the best way if you want to "custom tweak" you sound.

Yeah, I see what you mean regarding the ohms scale albeit the vertical axis. The review mentions that the Dentons are 4 ohm below 500 hz and 5.6 ohm over all. So, hopefully my Denon X3300 will do the trick. I am finally getting around well enough to get things up and running. Still taking antibiotics (3) times a day and the headaches can be quite overwhelming to say the least.

I also see what you mean regarding the Outlaw 5000 amp. It is truly a bargain no doubt. At 120 X 5 all channels driven is impressive. In 2 Channel it would be 150 X 2, no? Do you consider the 5000 to be neutral? Just curious. Thanks!


Cheers,

Phil