41–49 of 49 posts
Recently I purchased a “fosi audio” (brand names seem to rotate) stereo amp with bluetooth. It’s about the size of a raspberry pi.
It is plenty powerful to drive a pair of bookshelf speakers, sounds good, and connects to a turntable and bluetooth source at the same time.
$25 on ebay. Really hard to beat for the price and size
There are quite a few very, very good class D amplifier designs out there. “Very good” means highly efficient and with good enough fidelity (noise, distortion, etc) that no one will ever be able to distinguish them from perfect. But, IMO quite annoyingly, these things generally have analog inputs. This means you need a good DAC (which exists and isn’t terribly expensive) and a good connection from the DAC to the amp.…
I think you’ll have more success focusing on them as separate components as the power amp will always be in the analog domain
There are quite a few very, very good class D amplifier designs out there. “Very good” means highly efficient and with good enough fidelity (noise, distortion, etc) that no one will ever be able to distinguish them from perfect. But, IMO quite annoyingly, these things generally have analog inputs. This means you need a good DAC (which exists and isn’t terribly expensive) and a good connection from the DAC to the amp.…
It sounds like what you want is a dedicated class D power amp section and fully digitized dac/preamp section. I think you’ll have more success focusing on them as separate components as the power amp will always be in the analog domain
A good amplifier has better than 100 dB SNR. Your ear may have better than 100 dB dynamic range. Your sound system may have a bit less useful range, since your goal isn’t actual to destroy your ears. But 100 dB is a vaguely credible target.
So somehow you’re supposed to get a preamp and an amp, and you’re supposed to connect them, usually with RCA (unbalanced) cables. You’re supposed to get both devices to agree as to what voltage is full scale. And you’re supposed to get a noise floor, on the interconnect, better than -100dBFS. And you are supposed to do this with at least two separate cables plus whatever ground (or neutral) connections exist to both chassis, and this is all done near 60Hz currents that induce a voltage around every loop in question.
This is a tall order. At least the pros use balanced connections.
Or the industry could move to digital interconnects, where the DAC and the amp are connected by short traces on a PCB with a proper ground plane. And full scale on the DAC could be matched to the amp’s input.
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There is a picture of special, braided IEC power cable on there.
Geometry. Rigidity. It's POTENTIALLY legit. Here is a pretty science based primer on some of the things going on in the cable world. https://www.gcaudio.com/tips-tricks/why-power-cords-are-impo... One thing to understand about this niche high end cable market is that intellectual property just isn't a thing. There isn't enough money to fight lawsuits and wage war against copycats. Everyone loses throwing money away.…
https://gizmodo.com/updated-journalist-accepts-1-million-cha...
spoilers they didnt get the money, they didnt even participate :)
Don't see the point of this when I can just build a Kevin Gilmore Dynalo or Dynahi. Very low part count, almost BOM golf like; multiple variations by him and others to cover any case. Closest you will ever get to a wire with gain. Not to slight Hypex (the company behind the Ncore family of Class D chip amps), mind you, they're probably the only chip amp to ever succeed in making low distortion high output high effici…
aren't the Dnyaxx amps headphone amps?
Note: the best tweeters ever made have rather strange electrical characteristics, in the same vein that some headphones do. The Dynaxx family tends to handle anything, high or low ohm (even speakers that are 4ohm nominal or headphones that are 1000+ohm), but also ones with ridiculous impedance curves. People have realized that due to its exceptional tolerance of weirdly designed speakers, it makes for a good speaker amp too. 25w is enough to drive these tweeters loud enough, and some mids as well; woofers, no, not with a single board.
Kevin Gilmore also has sequels to his Dynaxx family (these being, themselves, improved versions of the KG Dynamic), due to some parts being replaced as they've fallen out of production and are hard to buy now.
Earlier quoted context omitted.
It takes a lot of computing power to reconstruct an audio sample well. Once reconstructed it takes massive massive amounts of storage. It's all about the Shannon Nyquist sampling theorum. "Strictly speaking, the theorem only applies to a class of mathematical functions having a Fourier transform that is zero outside of a finite region of frequencies. Intuitively we expect that when one reduces a continuous function t…
The thing is, if you design your input and output filter correctly then any sampled signal will be indistinguishable from the analogue source passed through the same set of lowpass filters. It does not take a lot of computing power, but it does take a couple of opamps.
"By contrast, the waveform reconstruction process – digital-to-analogue conversion – is not so simple. In an ideal world it would be achieved by generating an impulse of appropriate amplitude for each sampling point and passing the train of regularly spaced impulses through an ideal low-pass filter with its passband upper edge set to half the sampling rate. The impulse response of such a filter is the sinc function, so each impulse would generate a sinc waveform of the necessary amplitude, and the train of sinc functions would sum to recreate the original waveform.
This is illustrated in Fig 2, which shows six successive sinc functions of different amplitude and their sum (the black trace). Each sinc function contributes nothing to the summed signal amplitude at other sampling points, but does contribute to the waveform between the sampling points. It’s a common misunderstanding of sampling to suppose that the waveform between sampling points is unknowable but that is not true – provided that the input signal is bandlimited and sampled at least twice as fast as its highest component frequency, as required by the Shannon sampling process. In that case the waveform between sampling points can be reconstructed unambiguously. Importantly, the wave shape depends not just on the value of nearby samples but, ultimately, on the pattern of samples throughout the sampled signal" [1]
[1] https://drive.google.com/open?id=1QhJo_Rh8sQsItFvJ1g-MnNlg9p...
Or click the link here: https://chordelectronics.co.uk/explained-rob-watts-filter-te...
Earlier quoted context omitted.
Geometry. Rigidity. It's POTENTIALLY legit. Here is a pretty science based primer on some of the things going on in the cable world. https://www.gcaudio.com/tips-tricks/why-power-cords-are-impo... One thing to understand about this niche high end cable market is that intellectual property just isn't a thing. There isn't enough money to fight lawsuits and wage war against copycats. Everyone loses throwing money away.…
_power cable_, the one you plug into wall socket - thats how you recognize audiophool scams. You maaaybe could claim some speaker cables are better in theory, but then no one cashed out Randi foundation 1Mil for coat hangar speaker cable challenge https://gizmodo.com/updated-journalist-accepts-1-million-cha... spoilers they didnt get the money, they didnt even participate :)
I also agree there are a lot of garbage overpriced cables.
I think it's important to remember cables are not measured under appropriate loads, and they aren't measured connected to real equipment.
The measuring equipment falls far far short in the Audio world. Take for example the Audio Precision APx555B. It's the best audio analyzer in existence, and if you go to audiosciencereview, there are now DACs that have measurements that are below the measurable threshold for this machine in certain regards.
Power cables are the same. Not measurable in a meaningful way.
Earlier quoted context omitted.
_power cable_, the one you plug into wall socket - thats how you recognize audiophool scams. You maaaybe could claim some speaker cables are better in theory, but then no one cashed out Randi foundation 1Mil for coat hangar speaker cable challenge https://gizmodo.com/updated-journalist-accepts-1-million-cha... spoilers they didnt get the money, they didnt even participate :)
The problem with this is that it's way too easy to to tell the difference between power cables. Even non audiophiles can hear the difference. This is also 15 years ago. Manufacturing has taken such a leap between then and now that even if it was in doubt then, it's certainly not now. Now it's simply a matter of taste, and the better way to represent the reality of cables is that it's subjective, they do sound differe…
Saying Power cables are also better, but just not measurable puts you square with the rest of magical scam audio crowd.
Earlier quoted context omitted.
The problem with this is that it's way too easy to to tell the difference between power cables. Even non audiophiles can hear the difference. This is also 15 years ago. Manufacturing has taken such a leap between then and now that even if it was in doubt then, it's certainly not now. Now it's simply a matter of taste, and the better way to represent the reality of cables is that it's subjective, they do sound differe…
You wrote a lot of nonsense. Randi was willing to pay $1mil to Anybody able to tell the difference between normal speaker cable from Circuit City vs audiophool product. Nobody EVER took the challenge. Saying Power cables are also better, but just not measurable puts you square with the rest of magical scam audio crowd.
Would be very interested in them. Seems like Randi is straying out of his lane on this one.