- May 8, 2010
This might sound like a silly question but what exactly will adding power amps do to the sound?Does it just make it easier drive the speakers or is there more to it?
Soopafly49 said:Thanks for the replies guys. looks like ive got some reasearch. Will I gain more control aswell if each speaker had its own power amp.
busb said:I may give a pair of the audiolab mono-blocks a listen - they would have to be very special indeed to beat the Primare.
CnoEvil said:busb said:I may give a pair of the audiolab mono-blocks a listen - they would have to be very special indeed to beat the Primare.
Have you ever heard Bel Canto?.....if not, it should probably be on your list as well.
busb said:Thanks for the suggestion. Their REF150S would do the trick & is class D with full switch mode PSUs for £1.5k.
The level of detail from the Primare was jaw dropping. The imaging through my Arros was sublime: individual intruments could be discerned from others, their timbre was highlighted & the different recording venues such as studio or concert hall were very apparent. Vocals were very nicely rendered where breathing augmented the feeling of being close. the mix didn't particularly get projected forward but had depth & the amp never ever sounded pushed - perhaps a bit matter-of-fact at times. Top end was grainless, not over-emphasised, detailed where as the bottom end went deep, tuneful & controlled my Arro's 4 Ohm load with ease. The combination really did show how cr*p many pop recordings are: anything with amplitude distortion (volume pumping) sounded compressed & poor but no proper Hi Fi at any price will transform poor recordings & I don't want a systen that rounds off rough edges like I did 20yrs ago when my hearing was better! When I returned to my Restek amp, it sounded distorted by comparison, the Primare sounded that clean. The only aspect I wasn't sure about was that other amps sound more dynamic but that could be down to distortion artefacts - on paper class D should not have a problem with dynamic shifts. The build quality was up to Primare's usual high standards, it wasn't mine so I overcame the temptation to unscrew the lid & look inside! I never realised just how much difference amplifiers could make to a system - huge!
CnoEvil said:If you haven't done so, have a read of this (even if it's about speakers, it covers what makes a good amp): http://www.whathifi.com/forum/hi-fi/speakers-lets-define-an-easy-load Power (as in lots of Watts), isn't always the answer....just read the adventures of Acalex and Roby, where a 35W amp walks all over a 500W one (in their opinion).
Craig M. said:that 35 watts could easily be misleading though if the amp can provide much more for short bursts (dynamic peaks). music doesn't need a million watt amp, probably around 10 would do it as long as it can respond with more when the peaks come along. a lot depends on the speaker it is attached to.
barefoot_sound said:One aspect of amplifier power that probably goes unrecognized its effect on speaker transient response – especially with regard to dynamic speakers. A dynamic speaker works by flowing current through a coil (or ribbon) that is suspended in a magnetic gap. As current flows back and forth, the coil moves in and out. It's just a particular type of electric motor. But, as you may know, an electric motor can also be used as an electric generator. If you force the coil to move in the magnetic gap, the system will generate a current in the coil. This is how a dynamic microphone works.
Generating that current also generates a magnetic field inside the coil that opposes the fixed magnetic field in the gap. In other words, as you push on the coil, the coil pushes back. The more current that is generated, the harder the opposing force - or damping force. The regenerative breaking systems in hybrid and electric vehicles work on this same principle where the current generated recharges the battery. But the maximum damping occurs when you actually short the terminals of the motor (speaker) because this presents the least resistance and allows the most current to flow.
Powerful amplifiers with high current capacity behave like very low impedance sources. In other words, connecting a speaker to a powerful amp is like shorting the speakers terminals. And we know that shorting the terminals generates the most breaking power in the coil.
Ok, so what does this have to do with transient response? We don't actually push on our speakers cones, right? As a matter of fact, we do push on the speaker – with the amplifier signal. The amplifier generates current to push on the speaker to make sound. Obvious enough. But what happens when the amplifier stops pushing on the speaker, or tries to force the speaker to move in a different direction? Well, dear old Isaac Newton tells us that objects in motion tend to stay in motion. The speaker diaphragm has inertia and it will keep on moving even after the amplifier signal stops. The speaker will overshoot changes in the amplifier signal and continue to "ring" in the absence of signal.
So how do we solve this problem? What we need is a good breaking system like we described above, right? And as we just learned, the best breaking comes from having a high current capacity amplifier. So if the speaker tries to shoot past its mark, we have the maximum opposing force to damp its motion.
perthpete said:Besides all of the above mentioned comments (and I love the explanatoin about the pushing back speakers as well!!), one other important aspect is obviously budget and also where you are coming from .. My (simple) situation:
I've got B&W CDM7 se speakers (for about 12 years now). They have always been driven (as part of a surround setup) by a surround receiver (Always Denon so far, currently 3808 specced at 7x130W). I have never had any complaints about the sound. Untill the day someone came over with his power amp (Modwright 2x150) to 'show' how different that would be... Got to say it was an amazing difference. The speakers opened up especially in the highs, and at the same time much stronger base as well. Effectively I'd say that the sound was now much more in balance (between low/mid/high). Interesting result being that we had less urge to crank up the volume..
Meanwhile I have now bought a Parasound A21 (2x250W) and got it in my system for a week. Same result!!
So for me it is absoultely clear that just power spec on itself does indeed not mean a lot. The build, design etc but probably mostly the potential for high current is one of the biggest reasons for the improvement (the Parasound delivers up to 60 amp per channel).
So my short answer to your question would be: More current first, closely followed by more power
How do I know if it has more current?
CnoEvil said:busb said:Thanks for the suggestion. Their REF150S would do the trick & is class D with full switch mode PSUs for £1.5k.
The level of detail from the Primare was jaw dropping. The imaging through my Arros was sublime...<SNIPPED>
You give very interesting insight......and I agree with you about the quality of the amp.
The Bel Canto is the only Class D amp that I have liked, which is why I suggested it (great CDPs and Dacs as well).