Is powerfull Amps only for low sensitivity speakes?

Kalali writes:

"An additional point against using high powered SS amps driving extra efficient speakers is most SS amplifiers produce higher levels of undesirable (higher odd order) distortion within their first watt or two just like but not quite as much as when they are pushed near their clipping limit."

This was - maybe sometimes still is - the problem with solid state amps and "lets drive the THD to zero" thinking. And yes, he is right withe the fundamental observation - tube amps naturally distort in a musical way; solid state tends to distort in a less musically way; but that is less a function of the devices than of how they are applied in a circuit. Honestly, that was all figured out and mostly mitigated decades ago. I even wrote papers on little pieces of how. So amps that behave that way are of the class of "bad amps designed by people who should have known better". A good solid state amp should have few nasty harmonics today. I’m frankly amazed at how far we have come in about 35 years. Heck, there are pretty decent sounding OPAMPS (!) today. really, again if you know how to use them (which most people don’t).

I'll also note that there is an implicit assumption that the amp is running in class-B mode, which, again, should never be the case for a serious high-end amp. It should run class-A for atlas a little bit (and after that don't bother me with subtleties, they are drowned out) :-)

Admittedly if you want bog power and low cost, it will sound like garbage, but that’s a COST issue, not a technical one. As I said above, the only problem with a big powerful amp is that you must spend money on that power and therefore didn’t spend it elsewhere.

Its easy to design "cost no object" pieces that are so impressive. Its much harder to make a great $1000 amp or whatever.

G

I have DeVore O/93's and an ARC Ref6/Ref 150se combo. The GS 50 is identical to the Ref 150se but looks much nicer. First, it is a very good and very quiet amp. Second, you are going to need a very good pre, and preferably an ARC. Someone else posted this and he was 100% correct-the GS150 is balanced only and you are going to want/need a fully balanced preamp. After that, you will need really fine cabling, particularly from the preamp to amp, but I have learned that my speakers are extremely sensitive to speaker cable too. 

But a powerful solid state amplifier allows you to use mostly far better inefficient speakers and avoid the distortion and non-flat frequency response of many tube amplifiers. Anyway, we are not going to persuade each other.

@willemj Actually I agree that a solid state amp with a lot of power is helpful with low efficiency speakers. If you do your matching homework, you can arrive at a pretty good solution.

Regarding the comment about tube amps- if the amp employs enough feedback, and many do, they will be just as flat as a solid state amp on a given speaker. All it has to do is act like a voltage source and tube amps have been doing that since the 1950s.

But there is a bigger issue- there is a lot more to high quality audio reproduction than just flat frequency response! The first problem of course is that such is just plain impossible because no speaker is actually flat. The next problem is understanding how the ear perceives sound and in particular how it perceives distortion.

Its that latter bit that is often where solid state and tube people part ways.

Distortion is heard by the ear as tonality. This is why tubes are often thought to be colored- because of the 2nd harmonic, which causes 'warmth'. People that don't understand that the warmth is caused by distortion often think that tubes just can't be flat; but that is not the issue!

But solid state amps have coloration too- and in their case as well, its not due to frequency response error- its due to distortion. Thinking that the small amount of distortion that solid state amps have as 'negligible' is a mistake.

The ear uses higher ordered harmonics to sense sound pressure (again, a fact that has been known for decades) so 'negligible' amounts are easily heard.

The ability to sense sound pressure is easily the most important aspect of hearing perception. The implication is its a Bad Idea to increase the harmonics used by the ear, unless high fidelity is not the goal.



 

Thank you again for all your comments. All are well noted.
kind regards,
ozan

A lot of interesting facts posted as well as a lot of interesting opinions.  Of course,  many times, Opinions turn out not to be facts, so,  I'm going to give one of each....
Fact:  Nothing says that sensitivity alone has Anything to do with the sheer sound quality of a speaker.  I've been building for near 40 years now.  This is a fact.  Well chosen high sensitivity parts can produce a high sensitivity speaker system.  Poor parts OR poor design will produce a lower quality regardless of Sensitivity. 
Opinion:  way back when,  We produced a particular speaker that was 97db sensitivity @ 8 ohms.  This particular speaker (15 inch 3 way) sounded great with Tubes and solid state,  but man,  when you put a really good big mama solid state amp on them with a great power supply,  these things reacted with dynamics like non other.  
So, my opinion, in general is:  High powered solid state amps can be a benefit to High Sensitivity speakers. 
Clear as Mud?  Tim