Jackman -
I am also curious about the max output capability of the Khartago. I would like to know if it has at least has as much into 4 ohms as it's 8 ohm rating. Now here's why.
In response to your question, an amp is capable of putting out so many watts at a given impedance, and will not put out as much into higher or lower impedances. If an amp "doubles down" into 4 ohms, then it is designed for 4 ohms, and is only half as efficient into an 8 ohm load.
If an amp puts out 100 watts into 8, 200 watts into 4, and 400 watts into 2, then it is a 400 watt amp. It is not 100 watts. It also does not "double down". The fact is that it "halves up", so if you have a high impedance speaker, then you are paying for a 400 watt amp, and you are only using 25% of it.
The Stratos is good for a max output of ~185 wpc RMS. It targets a lower impedance than 8 ohms clearly, since its rated at 150 into 8. With my 5 ohm speakers, its probably like having around 170 wpc RMS. What I was bringing out about what's important also; some amps don't control drivers as well, an area where I feel the Stratos excels. I get a sense of having at least as much power as I can use, if not more. There are amplifiers that produce 400 wpc that do not manhandle my speakers as well. Its a great amp if a person needs the sense of power they get from a well designed product, which IMHO is so much more important than total wattage output.
If you have an SPL meter, I urge you to try and see how many watts you actually push your amplifier to. Using the Rotel RB 1090, which is 380 wpc into 8, and somthing like 700 wpc into 4, and I have a 5 ohm speaker, so I'm looking at around 600 wpc. That amp cannot make my speaker go louder than my 80 wpc Denon, which produces 140 wpc into 4, or I would guess around 125 wpc into 5.
Now the SPL meter. With one speaker playing, I should get 87.5 dB SPL with 1 watt of electrical power. The woofer itself will travel to around 18 dB over that, and then its done - it can't travel any farther. 18 dB over the 1 watt rating means double it 6 times -
For ONE speaker:
1 wpc - 87.5
2 wpc - 90.5
4 wpc - 93.5
8 wpc - 96.5
16 wpc - 99.5
32 wpc - 102.5
64 wpc - 105.5
(And add 3 dB for 2 speakers playing at the same time). Both speakers playing, I'm done at 108 dB - there is no amplifier in the world that goes farther than that - period. Not with my speakers.
So the truth is, the Denon gives me 108 dB in my livingroom, because it has enough power to do so. So does the Stratos, so does my roomies old Sony receiver, so does a NAD C370, so does the Rotel RB 1090, a Heathkit, a Sunfire, a Bryston, a Carver, etc. They're all done giving me power right there, at about 64 wpc PEAK, or about 6.4 wpc continuous (at 10 dB less than peak - typical). Oh yes, those peaks are also quite temporary and so they could subsist on storage, which brings us back to the continuous, or 6.4 watts per channel, power consumption.
There just aren't enough good guys in the world left, it seems, who know that a 40 watt amp can blow your windows out. I learned that from my electronics teacher in high school - coming from back in his day. Meanwhile, the marketplace is a frenzy, and electronics dudes who are also just loony tunes over massive power supplies abound. Out of their sights - they may never know. Another really telling tale here - the Rotel. I'm getting 600 watts here. Will I ever see it? No! But thats what it delivers based upon its parts and design. From the standpoint of my needs this is all quite incidental.
The next matter that comes to mind - what does it sound like? And I would like to assure you that this is the only remaining criteria. The
sense of power I get with the Stratos with its speed and control is the greatest of all of these. Maybe it's the right amount of feedback, who knows exactly why, attribute this to its balance, topology, design.
It's also an efficient piece of equipment. It doesn't meet those outlandish marketing requirements, as I would call them, to "double down" to 1 ohm. The only people who can conceivably use what those kinds of amps are capable of (which IMHO doesn't exist) are people with really outlandish speakers, because these amps are incredibly inefficient with real world loads. And, there's no stipulation that they don't sound like crap.
Actually, all they're really saying is, "more than enough watts into any load you've got or will ever get", and they have to build 1000 watt amplifiers to back up their claims, and meet the ignorant market smelling like roses. While I will never
use a 1000 watt amplifier, I will try not to hold the inefficiency of the design against them, because it may also sound great or perform really well.
Stay aware of accolades for amps that don't "double down", because it is ignorance in the consumer marketplace that cries "Witch!" without a good platform to stand on. Next, they'll say it has to float.
Last point I can think of. All the SPL levels discussed will cause hearing loss, and you'll know about that when you get older, if you want to listen at these kinds of levels for extended periods. Please check the OHA charts. Thx.
