Geof will then rewrite all the textbooks on the subject as well I'm sure. :^} |
Most tube amps soft clip so effects of not enough power are
not as unpleasant. Other than that, a watt is a watt.
What's different is how far a watt can be made to go. Soft
clipping helps. Limited bass extension does as well. These
are things that can help make a speaker seem more
"efficient". You need exponentially more power to deliver
a lower frequency at a certain volume level. That's
physics....basically how things work no matter what anyone
might claim. That's why a table radio with just a few
watts and limited bass extension might sound clean within
its limitations at a louder volume. |
Do
That's like saying why ever buy the more expensive tv if they are both 52 inch. Or the more expensive car if both have same horsepower engine.
With technology no single spec ever tells the whole story. In fact specs as a whole cannot. No two amps are exactly the same. There many differences some subtle and some profound. Quality being just one general category. Same as with any complex piece of technology. |
A watt is a unit of quantity and all are the same, but each case is different regarding the characteristics of each watt produced and how it sounds. Same amp can perform radically different with different speakers.
So saying a watt is a watt is true in theory in terms of how much power is generated, but in practice, all watts will be different sounding case by case. So there is certainly credence in saying that and value in knowing it, but alone it still determines only one piece of the puzzle in practice. |
Bottom line is watts matter be you tube or SS but you gotta take all power specifications with a grain of salt because no specification completely and accurately tells you whats happening in regards to distortion, which all amps produce to some extent and in different ways, some less offensively than others. Neither SS or tubes own the game in this regard. |
I think there have been some designs over the years that advertised large headroom out of a more compact box in particular that were not very good sounding overall on teh grand scale of things. I had a Hitachi Class G receiver for many years that fit this mold.
But I would agree with Kijanki's depiction of headroom.
Soft clipping amps, tube or otherwise are another way to get around the challenge I suppose. Those cannot be accused of having large headroom at higher volumes. They are designed explicitly to LIMIT the headroom in a manner that is not overtly offensive to the listener. |
"The amp can put out a considerably greater amount of power for relatively brief periods of time than it is rated to deliver continuously, or the amp can **not** sustain power outputs that are close to its maximum instantaneous capability for longer than relatively brief periods of time."
Al, what's the difference other than worded?
Is there an amp not capable of putting out more power cleanly for a shorter period of time? Soft clipping amps which tend to lessen the need considerably and enable fewer watts to "go further" perhaps?
In any case, one wants to avoid the extra distortion that most amps will produce when pushed hard by not having to run them too hard. I think that's a good rule to follow in all cases. |
"Class A 500 wt/ch tube amp?"
That should do nicely if you can afford the power bills. Doesn't Ralph have one of those? |
I have a 500 w/ch Class D amp. Class D is a different beast. It is designed to deliver the power only as needed as I understand it. That's what enables it to be small powerful and energy efficient. It never breaks a sweat or sounds strained at ANY volume, is as musical as anything I hear. It also soft clips to boot I believe. I've never heard anything less than lovely come out of these.
I'd compare that to my old Hitachi SR804 Class G 50 w/ch amp that advertised 100 w/ch headroom as I recall. This was quite midfi at best in comparison but a very nice looking unit with a very good tuner. My conclusion is that switching technologies that enable such things have come a long way and are now capable of doing things as well as most anyone might expect or need.
I also have a 60 w/ch Class D integrated with next generation Class D technology in it. htis does not go as loud but does exceptionally well, the best 60 watts out of an integrated amp I have ever heard by far. |
Makes sense. I hadn't really given the term dynamic headroom much thought of late with the realization that underbuilt amps that claim to be able to do great things for brief periods of time historically tend to not pan out that well.
But Al, how to reconcile Class D amps? I've seen headroom mentioned with them but not really a focus there either given the radically different way Class D operates. Its almost exclusively about delivering a large amount of power and current only at the times the music requires it as I understand the technology. |
"And also that amplifiers from different manufacturers using the same class D module will often have considerably different max power specs. "
I know that often different manufacturers interested in optimizing performance use customized power supply circuits to that end. Bel Canto with their M series amps is an example. Accountings I have read support the notion that the power supply used makes a big difference in class D amp performance as well, but given the nature of Class D switching technology, these can be much smaller and lighter than what is required to power comparable Class A or A/B.
I have also read of some high end Class D amp vendors using more traditional larger and heavier power supplies with their Class D amps to help assure the nth degree of performance I would assume. |
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Well, I learned something new about dynamic headroom and why it often is not a good thing when advertised even though it sounds like it is. These guys are trickier than big tobacco even!!! |
"That is the lack of the irritating harmonics present in solid state amps."
Present in many perhaps but not all. |
All Class D amps I have heard are the opposite of irritating. Go listen and see which ones you find irritating or not. I've heard Bel Canto and Rowland mostly.
Atmasphere has cited certain Pass amps and others I recall that are not prone to irritating harmonics as well. He would know best probably. |
All Class D amps I have heard are the opposite of irritating. Go listen and see which ones you find irritating or not. I've heard Bel Canto and Rowland mostly.
Atmasphere has cited certain Pass amps and others I recall that are not prone to irritating harmonics as well. He would know best probably.
I also recently owned a pair of SS Tube Audio Design Hibachi amps that advertised little or no negative feedback and would also fit the bill I would say.
I owned a pair of Carver SS m4.0t amps for many years that performed much like a tube amp. Those were designed to demonstrate a SS amp that sounded identical to a specific tube amp.
I've heard many other musical not irritating SS amps as well. If bad harmonics = irritating then these did not have that affliction either, FWIW. |
"A solid state amp that sounded identical to a tube amp? That's gold, Mapman, gold! Humor is the best medicine. ;-)"
Not to spoil your little chuckle, but that was Bob Carver who made the claim, not me. He's done a few things designing gear over the years but take it for what its worth.
I can only vouch for the fact that the amp was not irritating. Like most good quality amps, including tube amps, it sounded very good with the right speaker match. Harmonics did nt seem to be an issue. |
"If you really want an amplifier that is as smooth as a tube amp you are going to have to get a tube amp (its the lack of the 7th harmonic that makes them smooth)."
I suppose so. But having heard many amps of all kinds, including both tube and SS amps in what most would regard as "reference systems" I have found a tube amp is NOT what I want and I am happy with what I have. It provides hours on end of musical enjoyment. Irritation has been a problem in the past with some amps but is not an issue with the amps I use now, which are both Class D amps by Bel Canto. The TAD Hibachis were a hit for me as well.
There are many things that go into good sound. It either works or not. If i find it works well, i am not going to worry about individual theories about what's really going wrong. When it sounds wrong or irritating, I will do something about it, but it does not.
That's just my experience. FWIW. Not that I do not like the sound of a good tube amp, but having dabbled with tubes again in recent years, its all the rest that goes along with it that I still do not want.
I might feel differently if not for having found Class D to be a better option for me. |
Sorry I know nothing about what tubes will work best there. Others probably will. Cheers and good luck! |
