Amplifier current vrs watts; why is current more important?

Lately when talking to knowledgeable people in the audio industry I’ve been hearing how current delivery is more important than watts in determining weather an amplifier will drive a speaker.
So what exactly is current and how does it effect speaker performance? How can a amplifier rated at 150 watts into 8 ohms vs one rated at 400 watts into 8 ohms be a better match for a hard to drive speaker?

I'm far from an electrical expert but I'm starting to understand the above. So far the criteria I've gathered from research is to look for:

  • Amps that double wattage from 8-4-2ohms
  • Amps that are 2ohm stable
  • Larger power supplies

@christianb5s4 What is important is whether your amp can behave as a voltage source on your speaker. This does not mean it has to double power into 2 Ohms from 4 Ohms at full power even if your speaker does dip to 2 Ohms.

It will have to double power from 4 Ohms to 2 Ohms at less than full power. Do you see the distinction?

The only time there might be a problem is when you are pushing the amplifier hard, like really at full power as loud as the amp will play. All that will happen is if the amp isn't able to do the job at full power it will overload. So just make sure that the amp makes enough power to satisfy your requirements in your room.

IMO/IME its more important to get an amp that sounds like music, rather than to get one simply on its ability to double power as you cut impedance in half. That's a bit more challenging, since to get an amp to double power as impedance is halved will require (most of the time) that the amp also use feedback.

To use feedback properly without the feedback causing brightness and harshness, you really have to jump through some hoops on the design side and frankly, 99% of amps out there simply don't. What good does it do you to have an amp that can double power into 4 or 2 Ohms if it simply sounds harsh and no-one wants to hear it??


Thank you for the detailed response, I'm still learning about all the ins and outs of this topic but think I've gotten a decent grasp on it now. And I totally agree with your point on sound, I've never been a 'spec buyer' but like to balance good objective performance and subjective performance.


While my Arcam PA240 is ok at higher volumes, it lacks low-mid volume punch particularly in the bass department. And I want to get a better quality amp anyway as my system is at a much higher level than when I first got the Arcam.


For what it's worth, the amps I've shortlisted are Pass Labs x250.8, Parasound JC5, Coda 8, and Musical Fidelity M8 series. Also have Krell on the radar.

i have a mcintosh mc602 advertized as having 15o current per chanell! how doe's this stand??


my personal opinion -- get a modern pass, coda or krell, you won't need to worry about the speakers being well driven, the parasound and musical fidelity are (slightly) lesser units