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5V 3A PSU

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Ash View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ash Quote  Post ReplyReply Direct Link To This Post Posted: 16 Jun 2019 at 5:12pm
Hopefully all the procrastination over this product will be worth the final execution. I have my eye on one as I may also go down the "build-your-own-streamer" route and I respect how important a quiet power supply is in order to obtain a high purity of sound.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 16 Jun 2019 at 9:30pm
Some people have been convinced by the 0's and 1's argument, and believe digital audio signals are neat and tidy square waves. If that is true then why do they look like a crooked mess on an oscilloscope? Yes, they are supposed to be neat and tidy, but nothing's perfect, and if the power supply adds sh*t to the noise, then will a 0 be a 0 and will a 1 be a 1? Most of the time it will be gated by an input as such, but there will be glitches, and some will get confused.

Now, I'm sure some reading this will think I'm talking sh*t, but to those I have to ask when they started doing logic electronics with "noise free" CMOS? It was mid 70's for me. How about you? Cascade a number of CD4017's and you'll know it doesn't do what the data sheets claim.

Ah but, some will say we've made a lot of advancements since then. Yes, die sizes have shrunk making them faster... and more prone to EMI glitches!!!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ash Quote  Post ReplyReply Direct Link To This Post Posted: 17 Jun 2019 at 1:15am
Perfectly square waves are just a fantasy surely? Contemporary science says that electrons have mass (9.11x10^-31 kg) therefore they have momentum when in motion. 1 and 0 isn't just on or off; it is surely: electric field applied or electric field not applied. Take the electric field away and the momentum doesn't just disappear instantaneously. There is surely a brief delay, in the same way that acceleration from drift velocity would not be instant. In my mind, analogue and digital signals are just different types of electron motion, whether a pulse or an alternating current. Digital audio signals have a much higher electron oscillation frequency than signals in the analogue domain; the switching speed is much higher. When a charge is accelerated, it emits electromagnetic radiation (which is why the Bohr model of the atom with its fixed electron shells can't be quite right, cue orbital theory , electron probability, Heisenberg uncertainty principle etc). So if the switching speed for digital is much more frequent then isn't the potential for signal latency and motion lag etc higher too, if we're going to be consistent with modern accepted physics.

Edited by Ash - 17 Jun 2019 at 1:16am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 17 Jun 2019 at 4:07am
Yes, faster than analogue audio sine waves. Chip timing diagrams are interesting because they show propagation delays - slopes instead of verticals - so at least we're not being kidded there. However, they are simply diagrams which do not show real world artefacts, and actually, the data sheets do make mention of them so I can only assume "...a man hears what he wants to hear and disregards the rest" (Simon & Garfunkel "The Boxer").

Square waves being made up of the sum of harmonics of a sine wave, there will be a point where the nth harmonic exceeds system speed. Added to that are the unexpected real circuit inductances which cause 'bounce' or reflections, which run back and forth along a conductor, and even a short straight piece of printed circuit track has inductance which can be counted in micro-Henries.

Slow square waves as per my turntable speed controller will be exhibited nice and cleanly, but at 192 kHz it's a different story, and it isn't much better a couple of even harmonics lower at 48 kHz. These being repetition rates and give no indication of rise and fall times.

Then we have clocks with which to synchronise to, which are not clean square waves. So we have bursts of 0's and 1's which do not resemble the simpleton way they are perceived by our controllers, who exercise their ignorant authority upon us, backed by law, and we are reported to them by a "university Professor" (what? In hairdressing!?).

It must be 1984! Bring on the doublespeak...

Sorry, I only do the real world.

(I could go on and on about skin effect in ground planes and all sorts of EMC stuff mainly learned from a world renowned EMC expert; Keith Armstrong, who incidentally Big Brother uses when it suits, and who Big Brother disputes when it suits...)

Anyway, this all boils down to the neat and tidy square waves taking on an analogue 'look', and gates simply being high gain amplifiers (see JLHs original class A amp and compare with an early TTL logic gate) which switch at thresholds, if, and only if, the conditions were perfect, which they are not!

In other words, we are not much removed from a radio receiver, and I found it interesting to note that some really good ones use a laminated transformer, with a flux-band...

(Beware of men of fierce countenance)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ash Quote  Post ReplyReply Direct Link To This Post Posted: 17 Jun 2019 at 8:33am
"a story we agree to tell each other over and over, until we forget that it's a lie"
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 17 Jun 2019 at 7:21pm
Now here's a real brain-buster, so crazy we could never have made it up...

A customer was complaining of losing a channel on digital sources, but not analogue, with his Majestic. Ouch!

So, it being the loss of one channel it has to be in the analogue domain, doesn't it?

I mean, it cannot be the digital side because that's basically a "mono" thing. OK, there's the Left/Right clock interleaving it, but it's a single digital stream - one channel - yes?

Yes, it is just one channel, and where was the fault? The rotary switch! Yes, the switch that selects one of six, one-channel - one-channel - inputs.

But it couldn't be! No it couldn't be, but replacing the switch solved the fault.

Now I'm sure the ASA's informant will be straight on to the ASA again, but I'm very sorry, it wasn't me who tested it. It was the customer who witnessed it, and John C who found the fault. And John C cannot believe it either!!!

And neither can I, but that's the truth.
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