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Old 16th February 2012, 05:08 PM   #2501
dvv is offline dvv  Serbia
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Quote:
Originally Posted by Wavebourn View Post
The same answer.
Sorry, must be my off day, but I don't get it?
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Old 16th February 2012, 05:14 PM   #2502
tvrgeek is offline tvrgeek  United States
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Originally Posted by dvv View Post
Wanna bet?

Remember Einstein:

Only two things have no limits - space and human stupidity. I'm not sure about space.
Got to remember that one. I work with some rather quick people and need a few.

I remember seeing an add MB had about how their cars were so perfectly designed, they had five different "perfect" bolts to hold in their window regulator. At the same time GM used a tab and one sheet metal screw. If they weren't so busy putting the wrong bolt in the wrong hole, they could have done something about their reliably!
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Old 16th February 2012, 05:16 PM   #2503
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Originally Posted by dvv View Post
Sorry, must be my off day, but I don't get it?
Which stage in power amp provides more of power amplification? You can judge by resistance it is loaded on, voltage amplification factor, and it's input resistance.
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Old 16th February 2012, 05:21 PM   #2504
bcarso is offline bcarso  United States
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Originally Posted by abraxalito View Post

I think the halo has probably worn off digital a bit now. In my experience mass-market digital stuff sucks sound-wise, probably for the reason that you hinted at - that the analog bits have been done by digital designers, the analog ones long having departed (or retired). After all, its only app notes isn't it?


For the record I think the digital domain is a marvelous place and its advantages hardly need defending. However in the realm of power amplifiers "digital" is usually a misnomer, and a quite pernicious one.

I met with a smart and attractive woman who was looking for a "second opinion", having met with others who told her they could not easily predict what the cost would be to her company of fixing a serious problem with a Huygens-principle Fraunhofer-spawed 600 channel soundfield synthesis system. The designer had come up with an approach which used company C's power amplifier parts, 8 channels per chip, bits in and speaker levels out. What's not to like? The prototype system with hairy amounts of analog-line-level signal distribution to the upmteen powered speakers would be replaced with a simple fast bus and local modules grabbing their appointed words in round-robin and delay-compensated fashion. Again --- what's not to like?

Well, plenty. Company C's esteemed designers had figured on their amps being used one at a time, in a consumer home theater setting. Their outputs were beautifully synchronized one with another, as long as they emerged from the one chip. But. A big but:

There was a random component to how the modules started up and played, a variable and indeterminable delay, enough of a one to totally screw up the Fraunhofer protocols. Imaging destroyed! What to do?

Well in my usual naivete I thought about it and came up with a solution before the consulting clock was officially ticking. Or, actually, at least two solutions. One was elaborate, with a correcting adaptive system in the hybrid signal domain, which would allow the continued use of company C's "digital" amplifiers.

But the other, which I recommended, was to replace things with deterministic DACs and class-D amplifiers from manufacturer P. When I explained that this would provide superior performance, particularly with respect to power supply noise rejection, as it dawned on my potential customer what I was suggesting, her face took on a look of revulsion, as if I'd handed her a salad with a slug crawling in it, and she exclaimed:

"ANALOG?!?!?"

Last edited by bcarso; 16th February 2012 at 05:24 PM. Reason: spelling
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Old 16th February 2012, 05:43 PM   #2505
dvv is offline dvv  Serbia
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Originally Posted by Wavebourn View Post
Which stage in power amp provides more of power amplification? You can judge by resistance it is loaded on, voltage amplification factor, and it's input resistance.
Wavebourn, you keep answering to questions nobody asked. Please, re-read a few posts back to what was my question related to.

Post #2493.
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Old 16th February 2012, 05:56 PM   #2506
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Originally Posted by dvv View Post
Wavebourn, you keep answering to questions nobody asked. Please, re-read a few posts back to what was my question related to.

Post #2493.
In the post #2493 you write the same, but using more literature language, regarding some certain opamp-style topology, while my answer is more common and precise. In your example resistors loading stages with high output resistance are viewed by the next stage as part of output resistance of the previous one. Balancing such a way power amplification between stages you optimize the whole amp.
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Last edited by Wavebourn; 16th February 2012 at 06:00 PM.
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Old 16th February 2012, 06:03 PM   #2507
GloBug is offline GloBug  Canada
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Wow, slow down Wavebourn, this thread is starting to make sense.
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Old 16th February 2012, 06:04 PM   #2508
wahab is offline wahab  Algeria
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Originally Posted by bcarso View Post
Yes, hearing low-order HD with pure tones is tough. But how about the difference tone resulting from, say, 19kHz and 20kHz attendant on second harmonic-generating nonlinearities? And how about the low frequency (really d.c., but always limited by some electronic or physical highpass in the system) energy associated with 2nd?

Certainly higher-order distortions get more audible and weirder. But I do get a little tired of reading, accompanying the residual plots in the Stereophile sidebars, the commentary that so-and-so's distortion is predominately of the 2nd and 3rd, and thus subjectively benign.
It is wrongly assumed that odd harmonics sound bad.

A musical instruments produce all harmonics of a given note ,
even and odd ones wich are both important for the sound
brightness.

The ratios discuted here , that is 0.1% , should be even lower
than the dispersion level of said harmonics when comparing
seemingly identical models of a given instrument , let say
Guarnerius violins or Bosendorfer pianos, not counting
the instrument s changing sound with age..

That said , i m not a fanatics of high THD topologies
since a chain with 0.1% THD at each stage is a completly
different matter than the isolated case discussed above.
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Old 16th February 2012, 06:19 PM   #2509
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Originally Posted by wahab View Post
It is wrongly assumed that odd harmonics sound bad.
Does clarinet sound bad or good?
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Old 16th February 2012, 06:23 PM   #2510
bcarso is offline bcarso  United States
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Originally Posted by Wavebourn View Post
Does clarinet sound bad or good?
Depends a lot on the clarinetist
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