Densen amp
- Thread starter darian
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They claim a lot.
But the amplifier is only free of global feedback, and the measurements are somewhat less than stellar.
Have a look here for measurements on their flagship poweramp B350.
http://densen.dk/B-350/Stereoplay 6-04.pdf
@ 10 Watts the K3 distortion is only 40 dB down, and @ 100 watts a bit more than 30 dB down.
I also need schematics of the follow power mono amp:
Densen Audio Technologies
Substantial for high sonic quality are not the low order THD components (still high values without global NFB). Only high values of the high order components (>H7) results in bad sound, additional power compression of the power supply and bad GND management.
So I am sure that this amplifier sounds very good, without having heard them.
Densen Audio Technologies
Substantial for high sonic quality are not the low order THD components (still high values without global NFB). Only high values of the high order components (>H7) results in bad sound, additional power compression of the power supply and bad GND management.
So I am sure that this amplifier sounds very good, without having heard them.
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That I think is not true.
In my experience does amps that measures bad also sound bad, but amplifiers that measues very good, does not necessarily sound good.
So I think it is the other way arround.
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I do not really agree to that.
If you look at music, it contains even order harmonics, and none what so ever uneven.
Uneven harmonic distortions, has simply nothing to do with music, therefor the uneven are the most mallicious ones. In addition it is mostly the lower order uneven harmonics, which are these closest to the basic tone, that are the worst ones. But I do think higher order unevens are uneasy to the ears as well.
In this particular case something must have gone wrong. I´ve never seen any amp, which was not a tube amp, distort that much @ just 10 watts.
I say! That every amp measuring bad also sounds bad.
And I also say, that good measuring behaviour not at all excludes good sound.
Anyone else notice that the amp linked http://densen.dk/B-350/Stereoplay 6-04.pdf uses a single IC per side, has to be class D for that much output.
Lumba Ogir:
If the standard measurements are performed (THD at 1KHz, sometimes at 10 KHz) is exactly this statement also my opinion. Would be selected for the THD measuring the frequency 100 kHz sine wave and for the IM-distortion the values 199/200 KHz (unfortunately, even today still not the standart) then all amplifier that measure good would be automatically sound good.
Kurt von Kubik: What means "Uneven harmonic distortions"? My scandinavian English is very bad. Perhaps you mean "odd harmonics" like third harmonics.
Some years ago I think the same about the odd harmonic low order components as you mentioned today. After I have heard and measure different circlotron power amplifiers (Graaf GM-20 and some diy projects) I don't think so, because there were mainly H3 to observe, both in the measurement as well as in the p-spice simulation. But the perceived sonic quality was (not only for me) at very high level and I was very surprised about this. Previously I had still assumed, that low order odd harmonic distortions causes very worse sound but now I am shure, that worse sound it is caused only by very high order THD components, what means at the same time low order intermodulation products. In this case the follow article about THD spectrum through global NFB is certainly of interest:
http://www.its.caltech.edu/~musiclab/feedback-paper-acrobat.pdf
What dramatic effect can have a (not optimal) compensation has to be seen on my simulation results by
http://www.diyaudio.com/forums/pass...zero-o-os-0s-versus-later-aleph-versions.html
The wanted schematic I need to know more about Densen's DMCD circuit topology. It is hard to believe, that this is a Class-D (PWM/PCM) variation, as mentioned from diyAudio member jerluwoo
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Anyone else notice that the B-350 uses the exact same aluminium tension bar as the B-300 and the B-320, plus also the multitude of parallel emitter resistors for the output devices ?
Claimed 294 watts into 4ohms from a single IC with those smallish heatsinks seams to be alot for a typical AB/B amplifier. I can not read the language the article is written in though, just see the specs they give. Maybe they have a fancy trick or it has switching rails or something. Still big claims for a single IC.
The stk - 4048 II http://www.audiolabga.com/pdf/STK4048II.pdf ..can do 150w - 8R and might do 200+w @ 4R if properly heatsinked. The 4050 can do 200w/8 & 300+w/4. I have heard the 4048 in a big fisher and it can not hold a candle to a discreet OPS. The larger PS in the denson might improve on this.
Looking at the schema above , it is just a doug self based amp with 2 pair complimentary BJT outputs
.OS
Densen use 2SC2922 and 2SA1216. http://www.sanken-ele.co.jp/en/prod/semicon/pdf/2sc2922e.pdf
I´ve seen measurements on B350 according to IEC, where it runs to hot @ 4 Ohms.
At a time it was claimed to be 250/125 Watts in 4/8 Ohms and the first 40 watts should be class A, and they did not even state the impedance of theclass A power.
It was not class A of course, Densen even lost a lawsuit filed on someone who punked Thomas Sillesen for stating false data. The data proved false naturally, and he lost his case completely.
If looked upon, the data measured by the german magazine, makes it look like if the designed is actually flawed or something wird.
But that is much the way idiosyncratic design is done. You se to that distortion is high, and then call it something fancy. At Densen it is called "Airguitar factor", at Linn it is called "tunedem", and I think Naim calls it "rytm" or so. Linn and Naim though would not bring a product to market with data as measured on the B350. They have different ways of enhancing what they want their customers to be focused at.
At a time it was claimed to be 250/125 Watts in 4/8 Ohms and the first 40 watts should be class A, and they did not even state the impedance of theclass A power.
It was not class A of course, Densen even lost a lawsuit filed on someone who punked Thomas Sillesen for stating false data. The data proved false naturally, and he lost his case completely.
If looked upon, the data measured by the german magazine, makes it look like if the designed is actually flawed or something wird.
But that is much the way idiosyncratic design is done. You se to that distortion is high, and then call it something fancy. At Densen it is called "Airguitar factor", at Linn it is called "tunedem", and I think Naim calls it "rytm" or so. Linn and Naim though would not bring a product to market with data as measured on the B350. They have different ways of enhancing what they want their customers to be focused at.