I've been told in various audio shops that power amps will make a difference to sound quality, but they are often expensive to purchase. I have a pair of 87 dB sensitivity speakers with impedance dips down to 3.4 ohms. I'm currently using an AVR.
Thinking that more power will bring out the potential in the speakers. From a technical perspective, will adding a power amp result in audible improvements?
The speakers are fairly insensitive , you need to look for an amplifier whose output doubles ( it can't technically double ,but some amps get close) as the impedance halves.
If your current amp is providing enough current then it will be fine.
Keith.
You don't need an amplifier that doubles power to drive low impedances.
That is a myth. Further, the amp is making the current if its driving the speaker. Its mathematically impossible to not do that. BTW, the current needed really is not all that much, to drive 200 watts into 4 ohms is slightly more than 7 amps. What you need is an amplifier that drives the speaker
correctly. If the speaker is built along Voltage Paradigm design rules (which is probable, for more on this see
http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php) then what is important is if the amplifier can act as a voltage source. This does not require that the amp double power, and the results between one that can double power and one that can't but otherwise behaves as a voltage source will be inaudible.
Again: you don't need an amp that can double power as the load is halved. You do need an amp that can drive the load as it was intended. Keep that in mind!
Tube amplifiers can drive impedances that low if set up correctly (even our OTLs can be made to do that). While the resulting frequency response
may be exactly the same, the tube amps will sound different as
the distortion signature is different. The human ear converts all distortions into tonality, so you hear the various distortions that amplifiers make as a coloration. Solid state amps, while making very little distortion, happen to make a form of distortion to which the ear is extremely sensitive, in fact moreso than most test equipment. This is why many transistor amps tend to sound bright (which is a coloration), even though they measure perfectly flat on the bench.
Tube amps on the other hand make lower ordered harmonic distortions (although generally in much larger quantities), which are interpreted by the ear as 'warmth' or 'bloom' (another form of coloration). The thing is, this is shown to be much more appealing (musical) to the human ear (the term for this type of distortion is 'euphonic') and so such amps tend to sound more pleasant, particularly when the amp is driven close to or at clipping as opposed to a solid state amp driven the same way. This has led to the idea that 'tube watts' are more powerful than 'solid state watts' (the truth being that a watt is a watt, the difference being that the tube distortions interact more favorably with the human ear/brain system). Its also why tube amplifiers are still very much in production a good 60 years after the vacuum tube was declared 'obsolete'.
Before you invest in another amplifier though, perhaps it might be a good idea to look at how your speakers are set up right now, since that can have a huge effect on how well they perform. For example, any speaker that is low efficiency and low impedance will not sound right with long speaker cables! They need to be kept short- 6 feet or under being a good rule of thumb. OTOH, high impedance speakers (16 ohms for example) can tolerate longer runs without loss of impact or definition (by the latter, I mean things like really being able to make out lyrics and the like).
If the speakers are playing into the long end of the room generally they will work better (image well and play bass at the same time) than if playing across the short end of the room. The construction of the room and how its furnished can have a huge effect; generally speaking the room is half of the quality of any audio system. That means that a really good room can make up for an inferior system! Obviously both a good room and a good system is where you want to go with this. So you want to examine these issues first before replacing the amplifier!!
