2. misc-audio
  3. 1016666334

Current: Power Line and Amplifier Amp Ratings

Hello,

I have little knowledge when it comes to power and alot of specifications relating to amplifiers. Hopefully some people here would be able to assist me with a few items.

My electrical sockets are currently all 15 amp.

I use a Musical Fidelity amplifier, an A300 Integrated, and the specifications mention that it can do 20 amps.

Does this essentially mean that if the amplifier was required to put out this amount of current, that it is limited by my electrical setup, or am I looking at two specifications that aren't related to each other?

If these are related, would I find a considerable improvement in being wired for 20a, with a 20a socket? When I ask this, I am not looking to find if benefit would come from a dedicated line, or changing wiring, simply from a technical perspective, if all things considered, things remaining exactly the same, but being setup for 20a instead of 15a.

Also, often I will see amplifiers that have a peak current output of say 50a, or 75a. Are these essentially meaningless high ratings if amp current is limited by your electrical setup?

Even if the above is true, is there anyway based on knowing your speakers specifications and graphs, and a certain volume level at a certain listening difference, to estimate how much current your amplifier is actually generating at typical levels, and at peak requirements?

Using my speakers as an example, they are about 87db/sensitivity, and a relatively flat 4 ohms across the frequency range.

Is it typical to find that despite the _ability_ to push our rediculous amounts of current, that most amplifiers rarely need to?

Please excuse my complete ignorance when it comes to these matters -- I have listened to many components an systems and know what sounds good to my ears, but I am still trying to understand some of the core concepts behind audio and power.

Creating short lists, and auditioning, buying value, buying quality. These are all positive things in the search for what you're looking for, but I'm sure that me understanding requirements and claims will also help me to determine exactly what and how much of certain things I need, and what is overkill.

Thanks for your help.
paris47a19e7

Showing 1 response by jameswei

jameswei
883 posts
 
Wattage equals the resistance times the square of the current. W=RxIxI. If power were 16 watts and resistance were 4 ohms, the current would be 2 amps.

By the way, the capacitors in your amp's power supply store energy like a water tank stores water. The tank is capable of delivering a high volume of water until it is depleted, even though it's refilled at a much slower rate from the pump at the well. Similarly, your power supply capacitors are filled relatively slowly from the wall current, but your amp is capable of disseminating current at a faster rate until the capacitors are depleted. Most usage requires very brief bursts of high current to support musical peaks so the capacitors almost never get fully depleted. Relative to the needs of the music, they refill quickly enough.
More to discover