High Current vs high power


Hi!

Often you hear/read comments that the current matter more than the power (example Nait) and one should look for high current more than high power etc.?

Can anyone explain that or debunk the myth (my limited physics knowledge tells me that power and current are interrelated for the same voltage and impedance)?

Also, which amplifiers (pre power or Integrated) have 'higher current' than their peers at same power ratings? Is there any specification that shows the current capability of the amp which one can read and compare? like power, THD etc.?

Thanks
K
kelpie
Zd ... more than you know, I agree with what you said about live auditions. A while back, I posted a comment about road testing two sets of speakers at a dealer friend's shop. Coincidentally, he had just taken in trade an ARC VS-115 tube amp, which until a week ago was the amp I used. That's about as good as it gets for "A/B'ing" speakers. I was quite surprised that a speaker similar to my current fronts ("Brand P") cleaned the floor up with Brand X. Was it the gear, the room, the cables, the amp??? Dunno. But in "theory" Brand X should have cleaned up the floor with Brand P. Go figure.

But here's the dilemma. How often can one fairly audition speakers, amps and other gear given the paucity of high end B&M stores? Forget being able to control all the variables, like using the same model amp when comparing speakers. At least in my neck of the woods, forget taking gear home. Doesn't happen.

OTOH, I find the subject of speaker/amp electrical compatibility interesting. Grasping the variables, many of which are EE design trade-offs, is challenging. But that's me.

Cheers

Bruce
The Rowland 8Ti is a good example of what I was talking about.

Into 4 ohms it is rated 400 watts, but the current figure states(from the website):
50 amps continuous, 100 amps peak

Its pretty obvious this has nothing to do with power! 50 amps continuous into a 1 ohm load would be 2500 watts, yet we can see from the specs that the amp is unable to double power between 8 down to 4 ohms. Even it if could continue to double power to 1 ohm, the output power would "only" be 1600 watts.

What is being stated here would seems to be that the power transformer can provide 50 amps on a continuous basis. I suspect though that if that were to actually happen it would blow its mains fuse in less than a second.

So what we can conclude without speculation or debate is that this 'current' figure is not a real-world spec so much as it is a measure of the capacity of the power supply. I have seen, FWIW, tube amps with this much and more 'current'.
"But here's the dilemma. How often can one fairly audition speakers, amps and other gear given the paucity of high end B&M stores? Forget being able to control all the variables, like using the same model amp when comparing speakers. At least in my neck of the woods, forget taking gear home. Doesn't happen."

I agree that you can't control all of the variables. The good news is you don't always have to. I'll use myself as an example. I'm very picky when it comes to high frequencies. If a system can't get hf's right, I can't listen to it. I don't find it too difficult to judge components in this area under less than ideal circumstances, like a dealer. Given the fact that hf's are very directional, room acoustics don't factor too much into the equation, at least for me. As long as there's nothing in the way between myself and the tweeter, I can usually pick out what I need to.

Now look at another area; Bass. That's much more difficult because the room is so important. That doesn't mean a demo is worthless. Trying a certain amp with a certain pair of speakers can, at least, give you some info, but you are still taking a chance without listening to the system in your room.

So, where I'm going with all this is to say that you shouldn't give up on demoing equipment just because you don't have ideal conditions. Pick the areas of sound quality that are most important to you, and focus on those. Sometimes you have to get creative. Sometimes you have to have to take a road trip. That's just the way it goes. I learned from some very costly experiences, myself. I have no problem at all driving several hundred miles to get to the 1 dealer that will lend me the CD player. And then drive 2 states over because that's where the speakers are. (With the rest of my system in the car, of course). Why? Because its so much easier to spend it, than earn it!
08-26-13: Bifwynne
Al and Ralph, it amazes me how this technical issue just keeps on giving.
LOL! & so true...
but it's good to see that more & more people are beginning to ask this question & are desirous of understanding this electrical interface. This is good! I'm reminded of a clothing company that I * think* is no longer in business - Syms - their slogan was "an educated customer is the best customer". I feel the same for this hobby (obsession?) of audio. The more the users understand, the more the manuf will be vary of try to pull wool over the users' eyes & the more truthful the specs will be.
On the flip side - Look across the pond in the EC countries - hardly anyone over there buys audio equipment based on specs. And, they manuf some really nice sounding gear!
In the USA (& maybe Canada too?) we are obsessed with specs & make that our guiding light in our decisions....

Kelpie, i 2nd Bifynne - read his other threads where several of us have contributed to clearing up the air. It's extensive reading but it will help a lot.