A question on power.

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What's the deal with amplifier power?

I demoed some spendor A5's today and the 75W amp (Roksan Caspian) was clipping before any decent volume levels. But I was once told that amps actually play at like 4W and 20W of music would make your ears bleed. So why couldn't the amp handle them?

Incase anyone's interested in the demo.... We switched to a 250W Musical Fidelity although it was louder, the small drivers (5") were bottomming out before it was remotely party volume. Later at a different shop I heard some PMC GB1i's which I actually thought went louder despite only a single 5" driver. Their clarity was amazing and really punchy as well, down low.

 

[Anonymous]

It's a mixture of things probably. The speakers may have awkward impedance or very low sensitivity which will drive the amp very hard. The amp itself needs to have decent current delivery to be able to work awkward speakers. It's not just a question of power.

 

[Thaiman]

It's all depend on quality of "watts" rather than quantity of watts.

I had 25 watts Vitus turn up as loud as concert hall level without problem, Mcintosh at 60 watts also can go so loud without become aggressive or bright. My wife's (2nd) system is KW250s and it will clip quicker than most!

 

[Anonymous]

Thaiman:
It's all depend on quality of "watts" rather than quantity of watts.

I had 25 watts Vitus turn up as loud as concert hall level without problem, Mcintosh at 60 watts also can go so loud without become aggressive or bright. My wife's (2nd) system is KW250s and it will clip quicker than most!

Yes, absolutely agree.

It's whats behind the op-amps that gives the effortless power, and that's where the expense is!

 

[shooter]

Thaiman:
It's all depend on quality of "watts" rather than quantity of watts.

I had 25 watts Vitus turn up as loud as concert hall level without problem, Mcintosh at 60 watts also can go so loud without become aggressive or bright. My wife's (2nd) system is KW250s and it will clip quicker than most!

Hello Thaiman, your getting between 113db and 116db peaks at regular listening distances from a 25w amp or do you have your head in the speaker??

 

[Anonymous]

trevor79:Thaiman:
It's all depend on quality of "watts" rather than quantity of watts.

I had 25 watts Vitus turn up as loud as concert hall level without problem, Mcintosh at 60 watts also can go so loud without become aggressive or bright. My wife's (2nd) system is KW250s and it will clip quicker than most!

Yes, absolutely agree.

It's whats behind the op-amps that gives the effortless power, and that's where the expense is!
Really? Can you explain in any greater detail to me as I'm very interested but don't have the electronics background. I bought the best OP amps I could find for my Quad and always understood that they affect resolution and detail but I never considered them a factor in the power handling.

 

[Anonymous]

The reason music often lacks body and sounds thin and brittle is due to current demand and the amount of reservour capacitance and quality of the Diode bridge in the amp/amps which effects the recharge rate of them.

For example adding a PSX unit onto a Cyrus Amp gives a much fuller and effortless sound.

The Quad 404 upgrade that you have made will have made a good improvement to it.
Many years ago I ripped out the power supply, rebuilt and modified the circuit boards on a 303, fitted a modded Cyrus PSX unit to it and the sound was amazing, valve like with power!
Driven by 60,000uf bypassed capacitance off a big Transformer through a fast diode bridge not restricted by fuses (circuit breakers) and kimberkabling internal/external.

To this day one of the most musical combos I have ever heard.

 

[Anonymous]

Cheers Trevor. Yeah, the Quad upgrade certainly provides more of everything including dynamics, richness and naturalness. At some point I'm going to go for another to make a mono pair so I'll end up with 40,000uF per channel as opposed to the 20,000uF I have now. Not bad.

 

[Frank Harvey]

milo: I demoed some spendor A5's today and the 75W amp (Roksan Caspian) was clipping before any decent volume levels. But I was once told that amps actually play at like 4W and 20W of music would make your ears bleed. So why couldn't the amp handle them?

Incase anyone's interested in the demo.... We switched to a 250W Musical Fidelity although it was louder, the small drivers (5") were bottomming out before it was remotely party volume. Later at a different shop I heard some PMC GB1i's which I actually thought went louder despite only a single 5" driver. Their clarity was amazing and really punchy as well, down low.This is a good example of the sort of thing I've been trying to get across on numerous threads on this forum. Many higher quality speakers do have awkward impedances, and even if they do state 8ohms, they usually dip to 4, 3, or sometimes 2ohms in the lower frequencies. Add to this low sensitivities, and you have a recipe for disaster if the right amplifier is not chosen. It's not only about choosing an amplifier that doesn't clip when pushed hard, but also an amplifier that can push hard and also have a bit of headroom so it can do it comfortably.

Watts per channel is a very rough guide, as it's more down to the output current that an amplifier can provide - 2 channel amps are better at this than AV amplifiers are.

In your case, adding more power did the job with the A5's, but there's always a limit to what a speaker can achieve when it comes to bass - it's physics. Some manufacturers use long throw bass drivers, which can take more punishment and go louder, but can lack speed and agility, whereas other manufacturers favour short throw for those exact reasons, as many people don't get to play at higher volumes.

Proac and ATC will take more power than the A5's can, with the Proacs being the easier load for an amplifier.

 

[aliEnRIK]

milo:
What's the deal with amplifier power?

I demoed some spendor A5's today and the 75W amp (Roksan Caspian) was clipping before any decent volume levels. But I was once told that amps actually play at like 4W and 20W of music would make your ears bleed. So why couldn't the amp handle them?

Incase anyone's interested in the demo.... We switched to a 250W Musical Fidelity although it was louder, the small drivers (5") were bottomming out before it was remotely party volume. Later at a different shop I heard some PMC GB1i's which I actually thought went louder despite only a single 5" driver. Their clarity was amazing and really punchy as well, down low.

Personally im shocked a Roksan wouldnt power them!

 

[Anonymous]

I have the A5s and Kandy K2 does a fine job! You have to keep in mind these are small floorstanders but they do go loud without distorting.

 

[Frank Harvey]

It'll all be dependent on the bass levels in the music. Stuff like massive Attack's Mezzanine or Boards Of Canada's Music Has The Right To Children will pose problems for the A5's, which will be a separate issue to the power one.