Current amp vs Voltage amp

This is a great discussion about the factors that go into good sound from a technical perspective.

Speaker/amp matching is perhaps the most important fundamental to get right first to achieve best results IMHO. Every system must have an amp and speakers and other things might help compensate but cannot replace a good amp/speaker match.

I am in the camp that says the happy path is to get the fundamentals right from a technical perspective first and tweak from there. Nothing is more fundamental than making sure the amp is up to the task of GETTING THE MOST out of the speakers.

ALso, shame on the high end audio industry for not making it easier for buyers to get the most out of these products. It would not be hard to come up with a quantitative system for the benefit of buyers to identify quality of amp/speaker matches. But the reality is its up to the buyer to be educated enough to make these decisions. Good luck! I suppose such a system would take a lot of the mystique out of high end audio, for better or for worse. I guess if it were beneficial to the vendors to do something like that, they would.

05-09-13: Charles1dad
Attempting to make tube amps more compatible to drive certain speakers could potentially result in a loss of their instrinsic "sonic attributes".

I think 'yes' if you don't make the tube amp big (& resultingly expensive). This seems to be the opinion of Al & Atmasphere as well. see quote below from Bifynne's post-

tube amp manufacturers will have to figure out a way to make their products able to do double duty and handle speakers that are designed and voiced to be driven by SS amps. Ralph and Al have made a point that such amps are heavy and costly.

For example, TRL (Tube Research Labs) makes a 800W/ch tube amp that can drive an Apogee Full Range speaker:
http://www.tuberesearchlabs.com/products/gt800.htm
no price mentioned. if you have to ask, you can't afford them! ;-)
They also make a 400W/ch power amp which is expensive!
http://www.tuberesearchlabs.com/products/gt400.htm & I believe that this will also drive a Full Range.
Steve Wolcott also makes some high power tube amps (might not be able to drive an Apogee but I'm sure that they can drive other tough speaker loads):
http://www.wolcottaudio.com/WA_presence.htm

yeah, the upshot is that to keep from losing it's tube attributes the tube amp will have to be big, bulky & expensive to drive tough loads.

One of the most interesting recent developments in audio to me is that newer high efficiency amplifiers at affordable price points now offer an alternative to easier to drive higher efficiency speakers, which is a popular current high end paradigm for optimizing performance.

Full range, quality high efficiency speakers tend to be big and expensive.

NEwer high efficiency amplifier technology is capable of taking a lot of the technical guesswork out of the equation and driving most ANY speaker well. PLus they are small and affordable!

Watch out! There's a new and very talented kid on the block!

Of course, a good technical match alone does not assure that a listener will like what they hear, but it does provide a solid foundation to work with from there.

Why are there speakers designed with widely fluctuating impedances and steep phase angles in the first place?

A woofer in a box will have a resonance that is expressed as a peak in impedance. If there is no accommodation for this fact either in the amp or the speaker, the result will be too much energy at the impedance peak.

In the Voltage Paradigm the amplifier power is throttled back. This effectively insures flat frequency response. In the Power Paradigm the box design puts the peak at a lower frequency to take advantage of the extra energy- but again netting fairly flat frequency response, but wiht the additional benefit of bass extension, which might well be up to half an octave.

Some speakers don't have impedance curves based on box resonance. With such speakers, the Voltage model falls apart. A good example is an ESL, whose impedance curve is based on a capacitor. It really works a lot better if the amp makes constant power rather than constant voltage. That way the amp can make power in the bass regions where the impedance is high. This is why transistor amps tend to be bright and bass shy on ESLs- and typically why owners of ESLs and transistors put the speaker too close to the rear wall, to get bass reinforcement. They are not realizing the full potential of the speaker.

Anytime a Voltage Paradigm product is used with a Power Paradigm product, a tonal aberration will occur. We audiophiles call that 'equipment matching'.

One could also ask why amp designers choose not to build amps that can deal with such loads?

(This question is posed in the context of 'difficult' loads with low impedance or high phase angles)

The answer here is quite simply, such amps that can drive such loads are usually incapable of sounding like real music, as they have design features that violate human hearing/perceptual rules. One common example is the application of negative feedback, which, due to propagation delays in the amplifier circuit, causes ringing distortion, typically odd ordered harmonics (5th, 7th and 9th) which are used by the ear to sort out how loud a sound is. This is a pretty fundamental hearing rule. Amps that violate it have the coloration of brightness and also come off as harsh.

If you want to get away from that you have to figure out how to make a low distortion amp that uses no feedback. As stated earlier, distortion often take precedence over actual frequency response errors by the human ear, IOW its more important to have low distortion than it is to have perfectly flat frequency response (which can't be counted on in the best of circumstances anyway).