wiseoldtech,
technology you publish here is old but not especially wise (sorry couldn’t resist the pun)
As for the nanovolt noise levels, I doubt anybody could measure them without liquid nitrogen cooled equipment. Standard digital oscilloscopes have internal noise floor greater than 80 uV.
Gerhard is a member with knowledge and excellent equipment for noise measurements so his statements are facts and not an opinion.
Again, assumptions regarding me and my equipment.
But I'm not here to nitpick over trivial amounts of some form of noise.
Batteries themselves have a "noise figure" related to them, so what's the point?
What I do involve myself in is reasonable sensible, conversations of things without having to dig down into formulas that have nothing to do with human hearing abilities, since this IS an audio forum, not some NASA rocket design laboratory.
Others can debate and argue their tails off with those rediculous and boring essentials, I won't be dragged into them.
No, you present your views as the one and only truth and are not interested in any form of discussion on the subject.
No its a DIYaudio forum. Read the strapline at the top of page. Note the word 'fanatics'. Are you sure you are in the right place?
Hmm,... I see... Home > Forum > Amplifiers > Power Supplies >....IC Voltage Regulators
I don't see any "Warning, this thread is strictly for unusually complicated and terribly obsessive individuals concerned with atom-level noises that only aliens can sense."
well...do you mean that aliens aren't entitled to listen to good music?
They certainly are!
Except that their hearing abilities extend from 0 Hz to the mega-hertz range.
They also can hear and be annoyed by power supply noise even after it's been filtered with a dozen 10 Farad capacitors and twelve chokes!
I think there's a couple of them on here as members.
Even if you are correct about the (in)audibility of power supply noise in general, you are factually incorrect.
Given that you are a retired tech, unless you are wealthy or enjoy spending tons of money on scopes, the scope you speak of is most likely using 8-bit ADCs at best with a mediocre noise floor and vertical resolution. Measured with a standard passive probe as well, I'm going to doubt your nanovolt.
You like to yell at clouds and think that everything worth using was invented when you were young, we get it.
Last edited:
>> Read the strapline at the top of page. Note the word 'fanatics'. Are you sure you are in the right place?
> Hmm,... I see... Home > Forum > Amplifiers > Power Supplies >....IC Voltage Regulators
OIC. His teletype machine does not render graphics.
___________________^^^^^^^^
{Yes, I have worked forums with Teletype users.}
> Hmm,... I see... Home > Forum > Amplifiers > Power Supplies >....IC Voltage Regulators
OIC. His teletype machine does not render graphics.
___________________^^^^^^^^
{Yes, I have worked forums with Teletype users.}
I see.
Follow the crowd or else, right?
Old School design is worthless today, ok.
Differing point of views are not welcome, apparently.
I get it.
The problem is their intolerance to any meaningful filtering capacitance. In practical use i find them not only noisy but also intolerably bass light.
wiseoldtech
In a technical forum, pursuing for extermely low noise level at PSU output is a viable activity.
If someone of us deems extermely low noise levels for his equipment as worthwile, is up to him and his application.
Unfortunately you mentioned the screen of an oscilloscope as the observation medium for noise at the nanovolt scale.
I would suggest you either provide this oscilloscope specs that support such an extraordinary ability or take back your claim, or accept the criticism to your extraordinary claim.
Not trying any corrective action, you end with posts that are damaging to your credibility, polute the thread and violate Rule #1
diyAudio Rules
George
In a technical forum, pursuing for extermely low noise level at PSU output is a viable activity.
If someone of us deems extermely low noise levels for his equipment as worthwile, is up to him and his application.
Unfortunately you mentioned the screen of an oscilloscope as the observation medium for noise at the nanovolt scale.
I would suggest you either provide this oscilloscope specs that support such an extraordinary ability or take back your claim, or accept the criticism to your extraordinary claim.
Not trying any corrective action, you end with posts that are damaging to your credibility, polute the thread and violate Rule #1
diyAudio Rules
George
Hi ! looking for some information about dual voltage power supplies for preamps in an interview with the Conrad Johnson designer he states that they prefer to realize voltage regulators with discrete parts and not using single chip voltage regulators. In their opinion they can have an impact on the sound ... and not for the good.
Looking then at some preamps schematic i see that in the late '70s and early '80s many of the TOTL solid state preamps actually used voltage regulators made out of discrete parts.
I guess the reason was that this IC regulators were not available ?
They are clearly handy ... but are they also completely fine to use in preamps ?
i would like to get some opinions ... i have a feeling that i was looking at the wrong part of the story ... the preamp circuit ... instead the secret of good sound could lie in the power supply design and construction
I am attaching one schematic just to explain what i have in mind ... more or less
You need to undo the unknowns, if we peer into the 78xx 79xx series, they have a constant 10ma of current, courtesy of a shunt resistance divider at their outputs, which many circuit designers, quite rightly will frown upon. You can see the schematic within these devices datasheets. Never the less other regulators can make excellent building blocks when used with discrete parts. Walt Jung has explored many of these possibilities.
if we peer into the 78xx 79xx series, they have a constant 10ma of current, courtesy of a shunt resistance divider at their outputs, which many circuit designers, quite rightly will frown upon
I don't think that is true. I certainly won't frown upon it. On the contrary, having a certain non-zero load at all times in general improves the regulation especially for small or greatly varying loads.
Jan
I don't think that is true. I certainly won't frown upon it. On the contrary, having a certain non-zero load at all times in general improves the regulation especially for small or greatly varying loads.
Jan
"I don't think that is true. I certainly won't frown upon it. On the contrary, having a certain non-zero load at all times in general improves the regulation especially for small or greatly varying loads."
Might be different with the frown, when you consider you could, but don't have choice of divider values, due to these being internal to the said regulator.
Might be different with the frown, when you consider you could, but don't have choice of divider values, due to these being internal to the said regulator.
- so the conversation came a bit hotter
. Wiseoldtech definitely knows how to bring a life into a thread.
But they need to be internal, that is the concept. You buy them as 5V, 12V, 15V etc, and the internal divider is precision-adjusted to the specified Vout at the specified accuracy.
Jan
I found something interesting comparing all the 78xx/79xx datasheet available online.The Motorola MCT78xx, although it doesn't have a great ripple rejection, it has a constant and lowest noise over 10hz...100khz.I'm not amazed that it is the lowest but i fear it is a mistake in the datasheet because it's the same in all 78xx series.At the same time the superior LM340 78xx series has a better ripple rehjection but significantly worse noise figures and it's also the same as in all other datasheet from other manufacturers, the noise varies with output voltage.It's only Motorla MCT series that has a constant and lowest 10uv noise in all 78xx series.What do you think?Is the datasheet wrong?
