[infinitesymphony]

Quote:

Originally Posted by mofonyx /img/forum/go_quote.gif Can you point me to amplifiers that require 45A of *peak* current?

Parasound HCA-1000A.

Your other questions are good ones, but I can't answer them.

 

[dvw]

You guys are talking about two different things.

mofonyx, what you are taliking about is what the equipment will draw from the socket.

Infinitesymphony what you are quoting is the capacity of the device can deliver in theory. The Parasound uses three pairs of 15A transistors. So the maximum capacity is 45A. But the amp can only deliver 200W into 8 ohm load. So the maximum current it can delivered is actually only 5 A without going into large distortion. Notice it also has 40,000 uF of capacitor, that's a lot of reserve current stored. I bet if you turn off the amp, it will play for another 3 to 5 second before it goes off. This is where the peak current comes from.

Usually, there is fuse at the power supply. But many people didn't realize there is also fuse at the output stage to protect the transitors.

What a good power amplifier is actually a good power supply. It can usually withstand lousy power line and peak power demand. IMO, if you have a good power amp, don't worry about power conditioner. And if you have a lousy amp, power conditioner is not going to help you.

 

[infinitesymphony]

Thanks for clearing that up, dvw. Your explanation makes sense.

 

[mofonyx]

dvw, so does power conditioners actually cause bad sound quality in any way?

 

[Ferbose]

Quote:

Originally Posted by LawnGnome /img/forum/go_quote.gif Household fuses and breakers are quick blow. As soon as you draw more than 15/20 amp, it blows. Why amps can have peak outputs greater than what you think a wall could provide, is because they have large capacitor banks. Remember, a lot of these sayings and myths are created by people who don't understand how these devices actually work.

Well, how power supply works and how power conditioner works requires real engineering knowledge, which I don't have. But I remember that the power supply of an amp only draws its current from the AC line for a few milliseconds in each of the 60Hz cycle. This means that the instantaneous current drawn can be far greater than 15A. But the house fuse or power conditioner won't blow because the power demand is not prolonged. If there is some filtering inside the power conditioner, I recall that it may cause phase shifts between current and voltage. This is what electrical engineers call power factor. Unfavorable power factor could cause some PSUs to work unfavorably. The amp itself also has to meet the transient demand of high-current output depending on the input signal. So we cannot simply thing in terms of continuous power. Also, there are capacitors in the amp and sometimes inductors/batteries in the conditioner that can store energy. What's behind a wall plug is very standardized, although what comes out of it can be messed up, because it is shared by many things in the household. What's inside a power conditioner can be very simple or complicated, and the circuit there in can interact with the circuit in the PSU. What comes out of the conditioner also varies widely due to design. Some computer UPS output weird waveforms which are very detrimental to audio equipment. Unfortunately, this is all too complicated for some one who is not an engineer like me.

There are solid engineering reasons that a power conditioner can improve or worsen certain components. But then again this is complicated business. In the pro-audio market, power conditioning is dominated by Furman. They have upscale power conditioners from hundreds to thousands of dollars. If they can dominate the pro audio market for so long, they must know what they are doing. But I guess most audiophiles like hi-end marketing more than solid engineering, and hence Furman power conditioners are not popular among audiophiles. Many audiophiles would much rather buy exotic power cords and audiophile power conditioners which are not even UL-tested. I just buy high-quality commercial power cords (try those shielded ones) and use a Furman conditioner because I am too lazy to think much about it.

 

[Patrick82]

I only use my Premier Power Plant to get modified sinewaves to add distortion to my system, the MultiWave and mass damping with books is a great combination.

 

[dvw]

Quote:

Originally Posted by mofonyx /img/forum/go_quote.gif dvw, so does power conditioners actually cause bad sound quality in any way?

Power conditioners should not cause any degradation in sound quality unless you have a defective one.

Think of it this way. All computers are powered by a power supply. It is the power supply's job to provide good stable clean power. Whatever artifact from the raw power should be filtered out. Power conditioners have not harm any data in these cases. In audio, the power supply are "usually" much better because of the current driving capability (there is always exception of course). So conditioners should not degrade the sound quality.

 

[Ferbose]

Quote:

Originally Posted by dvw /img/forum/go_quote.gif Power conditioners should not cause any degradation in sound quality unless you have a defective one. Think of it this way. All computers are powered by a power supply. It is the power supply's job to provide good stable clean power. Whatever artifact from the raw power should be filtered out. Power conditioners have not harm any data in these cases. In audio, the power supply are "usually" much better because of the current driving capability (there is always exception of course). So conditioners should not degrade the sound quality.

The computer analogy is not very useful. The digital system is designed to tolerate a large amount of analog noise and still function correctly. Look at those cheapo switching power supplies in the computer which output crappy power.

Two reasons that a cheap power conditioner can make audio worse:
1. Its filtering circuit raises AC line impedance, reducing the dynamics of power amplifiers.
2. Its circuit adds noise under certain operation conditions.

Read about it here:
PF-PRo

Although it is only product literature, it does describes some engineering principles and provide product measurements. It at least show how complicated power conditioning is for audio applications. The conditioner has to store power, reduce noise and provide surge protection, which is no small task. On top of that there should be voltage regulation, because house AC is really unstable nowadays, but this will cost you.

 

[dvw]

Quote:

Originally Posted by Ferbose /img/forum/go_quote.gif The computer analogy is not very useful. The digital system is designed to tolerate a large amount of analog noise and still function correctly. Look at those cheapo switching power supplies in the computer which output crappy power. Two reasons that a cheap power conditioner can make audio worse: 1. Its filtering circuit raises AC line impedance, reducing the dynamics of power amplifiers. 2. Its circuit adds noise under certain operation conditions. Read about it here: PF-PRo Although it is only product literature, it does describes some engineering principles and provide product measurements. It at least show how complicated power conditioning is for audio applications. The conditioner has to store power, reduce noise and provide surge protection, which is no small task. On top of that there should be voltage regulation, because house AC is really unstable nowadays, but this will cost you.

I respectfully disagree.

http://www.national.com/an/AN/AN-556.pdf

This is an introduction to power supply. Boring reading, we can skip that.

Low Noise Audio Power Supply Circuit - Maxim

Here's an application note on basic linear regulation. It has a noise rejection of 40dB and it is not using any reference with only a 10uF capacitor. Most linear regulator with bandgap reference today can have a typical 60dB or more noise rejection.

So the power supply itself actually acts as a "power conditioner".

The Furman is an impressive unit. But however, it is redundant. Reserve power is a nice touch. But it still have to go through the transformer of the power supply and the fuse. 45A will certainly blow the fuse. Unless the power supply of the audio equipment is really crappy, there is really no need for power conditioner except for surge protection. But if you have equipment with that bad a power supply, it is probably cheaper to upgrade.

 

[mofonyx]

Quote:

Originally Posted by Ferbose /img/forum/go_quote.gif Well, how power supply works and how power conditioner works requires real engineering knowledge, which I don't have. But I remember that the power supply of an amp only draws its current from the AC line for a few milliseconds in each of the 60Hz cycle. This means that the instantaneous current drawn can be far greater than 15A.

But your power cord is only rated at 13A, usually.

However, the rest of your arguement does make sense to me.

 

[philodox]

Try it both ways and listen. My amp sounds the same out of my UPC-200 as it does straight out of the wall, so I leave it plugged in to one of the zones. My CD player does benefit from the UPC-200 and is plugged into the other zone.

 

[mofonyx]

Hmm, philodox, I want to understand why it can be detrimental, because it didn't make sense to me before.. which is the point of this thread

 

[philodox]

No idea, but I would suggest just trying it with your different components and seeing how they react.

 

[Ferbose]

Quote:

Originally Posted by mofonyx /img/forum/go_quote.gif But your power cord is only rated at 13A, usually. However, the rest of your arguement does make sense to me.

What does it mean that a power cord is rated at 13A? It means that if the continuous current is higher than 13A for a long time, enough heat will build up to make it unsafe. Of course the current can be 45A for a very short time and nothing will happen to the power cord. 45A will easily flow through 16 gauge copper, or even 22 gauge copper.

 

[mofonyx]

Well okay then, that explains it.