Indeed, as far as I understand, the nCore is using an improved feedback loop that specifically reduces THD and IM.
Yes, it's in the whitepaper but from memory Ncore uses a 5th order loop UcD a 3th order, also 20dB more loop gain in the nCore.
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Right, I was going to check on that but seems the hypex web site is not feeling very well right now :-/
Anyway, it is just possible that the reason the nCore sounds better than the UcD is that Bruno's theory actually works...
Right, I was going to check on that but seems the hypex web site is not feeling very well right now :-/
Anyway, it is just possible that the reason the nCore sounds better than the UcD is that Bruno's theory actually works...
Good guess
The reason the site is down (look at the posts from 13-11-2012): http://www.diyaudio.com/forums/digital-line-level/164277-hypex-dsp-module-s-18.html#post3239982
if you're inclined, this is written by Bruno: http://www.linearaudio.nl/Documents/Volume_1_BP.pdf
maybe some people are probably assuming that everyone posting here knows all the background. NCORE, just as UCD employs high amounts of negative feedback to reduce distortion.
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You're right, but 1 of the things that sets it apart from the majority of the competition is that is does that over the whole audio range only dropping of @ 50KHz. Disclaimer: this is all from memory as the Hypex web site is still down.
edit: typo again..
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If i understand well, Bruno takes its feedback source AFTER the output switching frequency filter, witch is good to cancel the introduced non linearities of it but add at least 2 poles at the traditional 3 ones. That implies feedback high frequency phases have to be tuned in order to avoid oscillation when you want huge open loop gain and feedback. Such a 5 pole calculation is affraying and require high mastery.
it's been a while (8 years) since I studied control theory at the university so me going into the subject is not the best idea.
but yes, the feedback is taken post output filter.
only thing I can tell you is that Bruno mentioned a few times that his approach is not exactly textbook (he actually gave a few not so enthusiastic considerations about how control theory is taught in school). I would agree, the portion about non-linear systems was short and not even required for the exam. stupid if you ask me.
I know it's a very long thread but there are some technical portions with Bruno's involvement that concern the above (as far as I recall).
the Hypex website seems to be recovering. it contains a few general (not extremely technical) papers regarding the subject. and there's an AES paper by Bruno. I have it by since it's not downloadable free of charge I'm not sure I'm allowed to post it. if you're an AES member and feel it's worth the 5 bucks, it's called "GLOBALLY MODULATED SELF-OSCILLATING AMPLIFIER WITH IMPROVED LINEARITY".
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My post contained a minimum of irony (which someone has taken), but also contains a truth.
I agree completely on the complexity in Human perception.
I do not agree however, to put science aside, which contains the actual facts. as cover so that they remain visible only things as convenience.
I often hear people say that ... the distortion in the time domain ... no, it has not been proven! .. So you do not have to worry...
but what they have to prove?...
The distortion in the time domain is the harmonic content of a musical instrument. I mean ... a set of "non-linearity" is the harmonic spectrum of an instrument and changes in relation to the frequencies of the musical note also. then, in the case of an amplifier, if we want that does not add or subtract, thus changing the harmonic content. we expect that with a very pure signal at 1kHz, the amplifier must not generate harmonics (still very low). this is in theory what you need.
obvious that there are many things that contribute to generate harmonics.
therefore, a sound is made in its nature of what you say ... it was not tried.
Regards
This was the subject of Bruno's presentation at the Burning Amp Festival in October. By including the filter, he gets a 5th order loop that, at a certain point, falls off at 100dB/oct.
Then he modifies the loop so that it only falls at a stable 6db/oct at the region where the ol gain goes through 0dB. Mastery indeed.
jan
I don't know, but there has to be something than explains it. I asked someone about it and they mentioned either a difference in the SMPS or "reaktiv motklobling" (reactive feedback?).
Dipoles are normally an easy load, but you used EQ quite a bit and had low sensitivty maybe the they were pushed on the border with UcD and the SMPS made a difference.
I'm just throwing out some thoughts, but I believe there's a techincal explanation behind just the fact that nCore surpasses UcD in the bass. I doubt it's related to distortion since dipoles have more of that.
Jan, did you mean Bruno is the son of mr Nyquist ? (Smiley here)
I paid the tax at a time, because i was obliged... No, i'm not any more ... in my barrel... ;-)
Food is not fantastic, cigars forbidden and no so much beautiful ladies... More, they speak a foreign language.
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There is nothing in the nature of dipoles that makes them an easier load than any other speakers.
In my case I have a lot of EQ yes, but that does not make the load any different from the amp's perspective. The impedance curve remains. I never exceed 20W output either, so any decent amp should drive them with no power or current limiting problem. And as it happens the EQ maximum is also where the impedance of the speaker is highest (around Fs). A walk in the park really.
More than that, and if we do not compensate each loudspeaker for motional impedance and inductance (i recommend that), the pick of resonance will be much higher than the same loudspeaker in a correctly tuned vented box.
This said, please take in consideration that, like Gaston, i'm on the no dipole side of the force ;-)
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I agree. People frequently talk of the bass improving, but it has absolutely nothing to do with the actual bass frequencies; it's actually the transients and higher harmonics being reproduced properly that creates the subjective impression of better bass. I have a system with bass reproduction capabilities that would be pathetic by most people's standards, but it is capable of creating the experience of extremely punchy, gutsy bass -- purely because everything above the lowest frequencies is done with pretty good accuracy ...
Frank
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