Hmmm, very interesting that the resister show such different results...
My humble guess would be that the amp has been designed to have it for a reason (dare I say it - it probably has been "tuned" to perform it´s best with that resistor). The altered nfb behavior and as a result (among other things) altered distortion characteristics may in theory be lower but if it (the "Total" harmonic distortion) is changed in composition it may however actually be more audible too...
Interesting that in systems with preamps large differences are detected (both the this particular resistor and in general too) and in systems without, nothing is detectable (almost ever) -reportedly neither cables, power conditions, the amp´s mechanical coupling, generally nothing can reportedly be heard on such systems...
In my humble experience, where the greatest improvements have been done are in the preamp. Had a simple buffer stage some years ago and though it sounded very clear, clean, and "linear" - but it never made real sense out of the "music".
Then I tried some more "bulky" preamp designs and though they didn´t necessarily improved the "HIFI attributes" such as cleanness and linearity (sometimes they actually degraded them a bit), they made much more sense out of the content - the music.
Have never looked back since, and removing the pre don´t "remove" the problem - it just "moves" it. Never experiences musical satisfaction from a system without a world class preamp in the chain. Reportedly recording studios spend insane amounts on their mic-preamps and have as a consequence to do much less fiddling down the chain with frequency/effects/compressors to get the best out of the source...
just food for thoughts
My humble guess would be that the amp has been designed to have it for a reason (dare I say it - it probably has been "tuned" to perform it´s best with that resistor). The altered nfb behavior and as a result (among other things) altered distortion characteristics may in theory be lower but if it (the "Total" harmonic distortion) is changed in composition it may however actually be more audible too...
Interesting that in systems with preamps large differences are detected (both the this particular resistor and in general too) and in systems without, nothing is detectable (almost ever) -reportedly neither cables, power conditions, the amp´s mechanical coupling, generally nothing can reportedly be heard on such systems...
In my humble experience, where the greatest improvements have been done are in the preamp. Had a simple buffer stage some years ago and though it sounded very clear, clean, and "linear" - but it never made real sense out of the "music".
Then I tried some more "bulky" preamp designs and though they didn´t necessarily improved the "HIFI attributes" such as cleanness and linearity (sometimes they actually degraded them a bit), they made much more sense out of the content - the music.
Have never looked back since, and removing the pre don´t "remove" the problem - it just "moves" it. Never experiences musical satisfaction from a system without a world class preamp in the chain. Reportedly recording studios spend insane amounts on their mic-preamps and have as a consequence to do much less fiddling down the chain with frequency/effects/compressors to get the best out of the source...
just food for thoughts
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In my tests I found that using a resistor that is around 3 or 4 times the Re of the driver already hit a sweet spot in term of distortion reduction (15dB of 3rd order distortion with my midbass driver, after having adjusted levels and EQs for the same final SPL of course).
amen to thatI'm still hoping hypex will produce a current source NCore, ideally a lower powered one or a dual channel NCore module but I wouldn't complain if it was a normal single channel one
With DSP being so widespread now the different driver response shoulnd't be an issue, would make an awesome combo with the DLCP for sure =)
Current drive with bass reflex will likely remain difficult though, as it will require very precise adjustements...
Nice conjuncture - but just a conjuncture. As stated before, the opinion from Bruno is that the nc400 should perform marginally better with lowered gain.
With or without R141, the distortion is so low that I doubt it causes any audible differences.
so it works in your specific system, as does with my tube pre and horns
but in most other combinations we have tried, the loss in sound quality was clear in different degrees
I just want people to be aware, its far from the best solution in all systems
Sure, and appreciated. But I think it is also appropriate to make sure people are aware that you are the only one to report the loss in sound quality, while several of us have observed the opposite. In absence of reliable ABX results, we can only take your observations as an individual, subjective view, for whatever it is worth.
Yes, though note the "should" as in theoretical deduction - any empirical evidence to back it? probably not...
(Ups, forgot the many subjective listening reports confirming the improvement, - sorry)
yes, ncore THD is VERY low and it´s audibility has surprised many. Why shouldn´t an even lower THD (and especially if changed THD) be audible too? After all we have been surprised before so why shouldn´t we be that again....
- And yes that claim is theoretical too and I have no evidence to back it.
Source-amp matching is probably the biggest issue after all
cheers,
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come on you guys, either Ray Charles or Stevie Wonder will do
in the extreme cases we heard the ncore with no R141, it was barely "Hi-Fi"
AND for the record IF you really need double blind tests: why even bother, what are your really looking for, just listen
next thing: I will be accused of all faults found was due to my ignorance of performing the secret snake dance before removing the resistor in the bare light of the full moon
Akasha,
It was by no means an attack, I was just curios how you came to that conclusion. Personally I found that I can't trust my ears in these situations, there's always a bias. Measuring is IMHO a far better way of trying to find out what's going on, double blind ABX is another way but only to compare X to Y.
But maybe that's just me being an engineer vs. you being a Hi-Fi enthusiast (I made an assumption here please correct me if I am wrong)?
Nothing wrong with that but I think we should keep these thing well defined so anybody visiting DIYaudio knows what's going on. Just my 2C..
It was by no means an attack, I was just curios how you came to that conclusion. Personally I found that I can't trust my ears in these situations, there's always a bias. Measuring is IMHO a far better way of trying to find out what's going on, double blind ABX is another way but only to compare X to Y.
But maybe that's just me being an engineer vs. you being a Hi-Fi enthusiast (I made an assumption here please correct me if I am wrong)?
Nothing wrong with that but I think we should keep these thing well defined so anybody visiting DIYaudio knows what's going on. Just my 2C..
Well, in that case something was definitely wrong with your set-up. Probably forcing your pre-amp into clipping.
"You hear what you believe". Have you ever heard of perceptual bias?
Once again: Pen & Teller: Water Waiter (the relevant part starts at 5:00)
Naah, you will just be accused of subjectivism and lack of scientific rigour...
so you neglect the fact that all listeners at the Copenhagen HI-Fi club meeting
laughed at the SMPS fed ncore or simply saying I'm not to be trusted in referring others opinion at all
so you neglect the fact that all listeners at the Copenhagen HI-Fi club meeting laughed at the SMPS fed ncore or simply saying I'm not to be trusted in referring others opinion at all
Well, yes, because not having been there, and not having been able to verify their reactions and your equipment set-up, it unfortunately comes down to "somebody claims that...".
I am not saying you are not to be trusted - I am just pointing out that all the evidence we, on this board, have is what you are telling us. Whether people trust what you are reporting or not is of course up to each person.
Those are facts, they are not meant as an attack or insult against you. It's just that some of us are engineers...
This is what I meant by "moving" the "problem".
Also, since it is a resistor in the nfb loop (please correct me) shouldn´t it alter the impedance that the input buffer stage "sees" when driving the modulator/cnore thingy which Bruno explained already was a rather difficult load (at least compared to the UCD) and which was a major reason for giving the input a fresh up. The point is - besides additional nfb removing the resistor probably also cause different operational conditions for the input and thereby also the modulator/n"core" circuitry. Could this somehow affect the input buffer´s sensitivity to the source´s output?
I'm engineer as well as audio-enthusiast for 33 years
I'm not doing a review and not talking about anything that is "a matter of taste"
Julf: no clipping distortion, pleeease!
I'm just simply saying to all ncore users: beware not all pre stages will drive the R141-less ncore with every speaker
shake your head or be aware, whatever you do just move on for G..'s sake
Well, yes, because not having been there, and not having been able to verify their reactions and your equipment set-up, it unfortunately comes down to "somebody claims that...".
I am not saying you are not to be trusted - I am just pointing out that all the evidence we, on this board, have is what you are telling us. Whether people trust what you are reporting or not is of course up to each person.
Those are facts, they are not meant as an attack or insult against you. It's just that some of us are engineers...
and some of us cant set us self free of that fact
music reproduction is NOT only about lowest distortion, I thought we left that back in the 80'es
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