I guess it is a power cord that increases power of a power grid.
They have that funny look on their faces "don't blame the messenger but you really need this".
I like to put the largest transformer that I can fit in the box, because I can! Why compromise?
Now, what are my real world needs? MY WATT 1 loudspeakers, paralleled by a VMPS sub-woofer average about 4 ohms, dropping momentarily to 0.32 ohms at 2K then rising again to 4 ohms. Kind of a lousy load from a pair of $5000 loudspeakers, but there it is! That is one example WHY I build my amps with so much short term power capability.
Now, what are my real world needs? MY WATT 1 loudspeakers, paralleled by a VMPS sub-woofer average about 4 ohms, dropping momentarily to 0.32 ohms at 2K then rising again to 4 ohms. Kind of a lousy load from a pair of $5000 loudspeakers, but there it is! That is one example WHY I build my amps with so much short term power capability.
It should be realized that a power amplifier of today, is 'ideally' a voltage source with virtually unlimited current drive capability. This is because many, if not most speakers, dip to or below 4 ohms, somewhere in the audio range.
You HAVE to spec for 8 ohms, yet design for 4 ohms or less. That is what makes a quality product, its power reserves.
You HAVE to spec for 8 ohms, yet design for 4 ohms or less. That is what makes a quality product, its power reserves.
A folk is asking:
What are the parameters required to be considered for calculating the power rating of these two resistors?
George
What's the explanation for an impedance like this? Is it really the only way to accomplish some goal? Difficult for me to accept, but whadda I know?
Thanks,
Chris
I suspect John did not design that speaker, so he does not know the answer. Also, I suspect the designer of that speaker does not know the answer.
John, you apparently misunderstood Wavebourn specs. Wavebourn specs mean the power supply have to be calculated for the peak power as if it is consumed constantly. Period. If peak power for such speakers means twice of power for normal speakers that means according to Wavebourn principle the power supply has to be designed for an adequate power. I.e. twice more than for 'normal' speakers.
But no matter how big are power requirements, calculation is the same: to satisfy voltage sag and overheating criteria. More than needed for this 2 criteria would be suboptimal, i.e. waste of money, space, weight, size.
CD Jitter
I agree that's a funny concept: perfect....anything!
When you say "work harder" I assume you are talking about increasing the current draw of the tracking, focus or head assy positioning motor(s)? There are indeed some poor quality players where the transport's DC power is drawn from the same regulated supplies as the analog output stages. It is a waste of time to critique this class of players for fidelity.
The analog optical preamp and level slicer are effectively immune to power supply modulation, since they are recovering code BEFORE error correction. They draw little constant current and are virtually always sub-regulated. Yes, with a poorly recorded disc, such an effect may push the error rate higher, but we will not confuse this discussion with that of the audible effects of poor quality discs. That is another issue entirely, a world of hurt is possible with discs that do not meet Red Book spec..
Your idea is perhaps applicable to a mid-line player where the owner is using the built-in D>A, and there could possibly be analog output supply modulation due to transport motor current spikes. There are two possible modes of sonic contamination: direct modulation of the audio due to poor PSR in the audio stage or clock modulation. In either case I would consider it to be a design flaw, so I won't waste time critiquing them.
When using external D>As, only the PCM output clock could be a source of contamination, and it is my experience that crystal clocks are pretty well immune to even moderate supply modulation, thanks to the mechanical inertia of the piece of vibrating rock. They are big, expensive and inflexible in output frequency, but what you get with a good quality crystal in exchange is good stability. I have never seen sidebands in output spectra as a result of transport motor current on a good quality player, and I've looked at a few. It actually was an issue on players based on the first generation Philips CDMC1 transport like the Revox B225, despite it's fabled status. I have not kept up with this aspect of CD transport performance recently, but I would hope the more recent quality players have this problem minimized to the sub 10pS/-130DbFS realm. This was attainable nearly 20 years ago in the 1990s, so hopefully it is better still today. Anyone have more recent experience than I in this matter? At that level, I would not expect the sonic degradation to be reliably audible, so I would move on to more pressing issues.
But that is just my limited experience, anyone else have more data?
Howie
Howard Hoyt
CE - WXYC-FM 89.3
UNC Chapel Hill, NC
www.wxyc.org
1st on the internet
I agree that's a funny concept: perfect....anything!
When you say "work harder" I assume you are talking about increasing the current draw of the tracking, focus or head assy positioning motor(s)? There are indeed some poor quality players where the transport's DC power is drawn from the same regulated supplies as the analog output stages. It is a waste of time to critique this class of players for fidelity.
The analog optical preamp and level slicer are effectively immune to power supply modulation, since they are recovering code BEFORE error correction. They draw little constant current and are virtually always sub-regulated. Yes, with a poorly recorded disc, such an effect may push the error rate higher, but we will not confuse this discussion with that of the audible effects of poor quality discs. That is another issue entirely, a world of hurt is possible with discs that do not meet Red Book spec..
Your idea is perhaps applicable to a mid-line player where the owner is using the built-in D>A, and there could possibly be analog output supply modulation due to transport motor current spikes. There are two possible modes of sonic contamination: direct modulation of the audio due to poor PSR in the audio stage or clock modulation. In either case I would consider it to be a design flaw, so I won't waste time critiquing them.
When using external D>As, only the PCM output clock could be a source of contamination, and it is my experience that crystal clocks are pretty well immune to even moderate supply modulation, thanks to the mechanical inertia of the piece of vibrating rock. They are big, expensive and inflexible in output frequency, but what you get with a good quality crystal in exchange is good stability. I have never seen sidebands in output spectra as a result of transport motor current on a good quality player, and I've looked at a few. It actually was an issue on players based on the first generation Philips CDMC1 transport like the Revox B225, despite it's fabled status. I have not kept up with this aspect of CD transport performance recently, but I would hope the more recent quality players have this problem minimized to the sub 10pS/-130DbFS realm. This was attainable nearly 20 years ago in the 1990s, so hopefully it is better still today. Anyone have more recent experience than I in this matter? At that level, I would not expect the sonic degradation to be reliably audible, so I would move on to more pressing issues.
But that is just my limited experience, anyone else have more data?
Howie
Howard Hoyt
CE - WXYC-FM 89.3
UNC Chapel Hill, NC
www.wxyc.org
1st on the internet
Oh dear, Howard, you have actually looked at the issue which others just talk about and worry about. You will have upset some people by assuring them that disc reading issues are very unlikely to affect sound, except where player design is very poor. They 'know' that disc reading matters, so your inconvenient facts (and inconvenient understanding of how players actually work) will not be welcome.
The trouble is, that in the hifi shop the label that indicates whether the player design is very poor always seems to have fallen off along the way ...
Frank
Don't know who they are. Found it on a gay porn website.
se
I'm afraid of those products that remove that last veil, particularly if the lady is dancing. I tend to lose my head.
It's their job, they take money to inform consumers, learning the technical aspects is simply due dilligence. Writers who simply act as apologists for every rogue outsider or tweak artist that comes along are just part of the fraud.
I find 6moons pretty good for spotting poor designs as they so often post up hi res internal pics. Reviewers are rarely experienced designers no matter which publication.
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