Indeed. Either you assume your senses are perfect, or you approach things in a scientific way.
I am not sure your 3 camps really relate to the "subjective" vs. "objective" split.
Subjectivism is king because people don't care about objective truth (and definitely don't want their preconceived notions to be shattered). 🙂
Subjectivism is great for making personal choices. They just don't provide anything of value to anyone else (pretty much by definition).
my apologies, i should have clarified. My setup is DSP XO in a PC to a multichannel DAC through USB. Final voulme control uses the DACs digital attentuator. At nominal listening around 70db, the signal level from the DAC should be quite low, hence my suspicion that the S/N seen my the modules is poor. Subjectively i do notice that playing louder seems to improve what i hear.
So the thought was to either put a balanced analog volume control on each analog output channel or reduce the amp gain so that i can keep the DAC signal higher for nominal listening.
So the thought was to either put a balanced analog volume control on each analog output channel or reduce the amp gain so that i can keep the DAC signal higher for nominal listening.
As I stated before, I would start by verifying that assumption - all you need is a simple analog attenuator (2 or 3 resistors).
Julf are you suggesting attenuator after the amp. I had indeed considered using an lpad on the tweeter for its 6db attenuation. But how about overall volume control? The line level is 8 balanced analog lines.
No, between your DAC and your amp. And you can do it one amp at a time just to see if it helps with your noise issue.
Separating or not separating SMPS
Hi all,
just wondering.... AFAIK all SMPS generates EMI.
Although SMPS by hypex are said to have low emission levels, what would hurts in placing the SMPS in a separate enclosure, if a good twisted and shielded cable (foil and braid, e.g. as per http://www.belden.com/resourcecenter/cablebasics/upload/Shielding.pdf) is run between the SMPS and the ncore module?
I mean, I can see more costs for an additional box (for each unit) and the (small) hassle of positioning it, but wouldn't this potentially bring to less RF pollution or - on the contrary - the added cables would act as an effective antenna
?
Ste
Hi all,
just wondering.... AFAIK all SMPS generates EMI.
Although SMPS by hypex are said to have low emission levels, what would hurts in placing the SMPS in a separate enclosure, if a good twisted and shielded cable (foil and braid, e.g. as per http://www.belden.com/resourcecenter/cablebasics/upload/Shielding.pdf) is run between the SMPS and the ncore module?
I mean, I can see more costs for an additional box (for each unit) and the (small) hassle of positioning it, but wouldn't this potentially bring to less RF pollution or - on the contrary - the added cables would act as an effective antenna
?Ste
So do linear supplies.
As long as you make sure the resistance and inductance of the cable is really low.
The risk is definitely there. I would start my verifying if the EMI from the power supply really is an issue - in my amps, with two SMPS600's and 4 nc400's per enclosure, it doesn't seem to be an issue.I mean, I can see more costs for an additional box (for each unit) and the (small) hassle of positioning it, but wouldn't this potentially bring to less RF pollution or - on the contrary - the added cables would act as an effective antenna
EMI is not an issue in linear supplies.
Here is a short and useful comparison between linear and SMPS (not comparing sound quality but simply the practical and technical differences):
https://www.circuitspecialists.com/blog/intro-to-linear-switching-power-supplies/
While I thought that article couldn't be more basic, the point about transient response was interesting. Theta made a comment once that they found SMPS lacking in exactly this area and hence why they favour linear supplied.
As for EMI, I understand that managing toroidal transformer 50/60Hz radiation (hum) to be a challenge. In a the 200W Class B amp I am building I've had an interior shelf in the amp made in iron to act as a shield between the twin PSUs and the rest of the amp.
As for EMI, I understand that managing toroidal transformer 50/60Hz radiation (hum) to be a challenge. In a the 200W Class B amp I am building I've had an interior shelf in the amp made in iron to act as a shield between the twin PSUs and the rest of the amp.
It most definitely can be. That is why some (perhaps overly obsessive) audiophiles are using stuff like shottky diodes. Remember that the current through the rectifier diodes isn't a nice, smooth sine wave, but a short peak at the top of the waveform.
Perhaps clearer to rephrase that 'linear supplies don't generally contain common-mode noise aggressors'.
The selection of rectifier diodes which minimise transformer ringing and suitably snubbing them (a belt and braces approach) is just common sense engineering.
Perhaps... but this wouldn't be one of them. If you haven't already, it is worth reading Mark Johnson's Quasimodo design note. (Just Google Quasimodo and diyAudio)
In any event, I suspect the issue of transformer excitation/ringing from diode turnoff is entirely different from transformer low frequency radiation.
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