DonR
Major Contributor
They make nice, cheap borescopes. Just wipe them down thoroughly first.And by that you mean endoscopes?
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Electronics for Audiophiles: Voltage and Current (Video)
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Source: Vladimír Kůla & Michal Kříž. INTRODUCTION TO ELECTRICAL ENGINEERING. CTU PUBLISHING HOUSE.
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Johannesthalos
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I have an amp that can do 26V@8A max. and that is able to deliver 1.6 ohm @26V@8A = 416W max. (2xMA12070@PTBL@400W supply)
My speakers are KEF LS50 Meta. As they have been reviewed by Amir, I know that they are rather "heavy loads" that will pull down to 3.2 ohm (83db sensitivity) and not only for short bursts, but for a quite a while. Officially they are marketed as 8 ohm speakers tho.
Questions:
a) Since my speakers go to 3.2ohm, I consider them heavily current-dependend and not very voltage-dependend (they are extraordinarily open/transparent with vocals and high tones anyways)
b) If I would swap my amp with one that does:
26V @8A @1.6ohm -> 48V @7.1A @2ohm
Would I even benefit from that considering the new amp could do more voltage, but slightly less current?
Would I even hear a difference?
Would the newer amp play louder vocals, but "miss out" on the base at some point, whereas the old amp would not "sag" and go a full "1:1 ratio" down to the very last drop of its 26V?
My speakers are KEF LS50 Meta. As they have been reviewed by Amir, I know that they are rather "heavy loads" that will pull down to 3.2 ohm (83db sensitivity) and not only for short bursts, but for a quite a while. Officially they are marketed as 8 ohm speakers tho.
Questions:
a) Since my speakers go to 3.2ohm, I consider them heavily current-dependend and not very voltage-dependend (they are extraordinarily open/transparent with vocals and high tones anyways)
b) If I would swap my amp with one that does:
26V @8A @1.6ohm -> 48V @7.1A @2ohm
Would I even benefit from that considering the new amp could do more voltage, but slightly less current?
Would I even hear a difference?
Would the newer amp play louder vocals, but "miss out" on the base at some point, whereas the old amp would not "sag" and go a full "1:1 ratio" down to the very last drop of its 26V?
this is all not how it works.
Even on the absolute basic level the speaker "pulls" the current and the amp feeds voltage. it is a voltage source. the speker is a load.
You can only multiply Volts and Amps if they are in phase. they are not with speakers. that's the difference between VA and Watts.
Your Power supply current can't be directly translated to speaker current (especially with class d).
How do you know the amp your using now has not enough power? is it clipping?
Johannesthalos
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No, in fact it feels very powerful. Never made it beyond 70% of max volume before my brains got blown out, since I am in a small room about 5x3m. Never heard any clipping.
If I am correct, I'd be getting a maximum of 3.2ohm@26V = 211.25W (from possible [email protected] = 422.25W) out of this amp with my speakers. That is halfed by the two channels, so I could expect this amp to deliver a maximum of 105,625W @3.2ohm per channel. KEF says the speakers are rated for 100W, but they also say they are quote: "8ohm(3.5ohm)" hence I am not sure if they take 8 or 3.5ohm as a pairing for that 100W. If they pair it with 8ohm they could take 200W@4ohm and therefore 211,25W @3.2ohm.
There is an active version of the LS50 Meta using a D-Class 200W driver for the base and a 80W AB-class for the tweeter. Therefore I figure they must be linking the 100W to 8ohm and I could run my speakers with double the power. Am I being correct so far?
The question is, would I benefit from it?
The quick answer is no. If it plays as loud as you want without the volume knob turned all the way up you are pretty good to go. As a consumer and not an engineer you have to use what reasonably works. If you have some headroom, you will be ok. A light bit of clipping is inaudible. Or, you can say I will buy a very big powerful amp and then never have to ever buy a new one until this one breaks from old age. It is your money. But, from what you have explained you do not "need" to spend the money. But, this is audio so need is never the issue, it is always a "want". So, it is up to you to decide what you want. You can get GOBS (technical term) of power with the new Class D stuff. Let us know what you do! Good Luck.
Johannesthalos
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There is an old saying in the hifi world claiming that a more powerful amp will sound fuller/heavier even on the same volume output compared to a less powerful one. But I believe this to be coming from older Class-D amps of which had insufficient ability to run high currents, resulting in a fading out baseline with rising the volume, thus becoming a "thin sound".
The KEF LS50 Meta will move their woofers visibly when being pushed on certain deep base tracks. Very few tracks will make them even start to move around 55-60% of volume.
As Amir stated in his video-review, once you can see the woofers on the LS50 Metas move and seperate from the tweeter, the base will start to distort slightly and even more when you push it further. Therefore I figure they cannot take any more current reasonably. But this is leaving a very important question. Since those speakers are already among the most demanding speakers one could buy at nowaday markets and since my "little" ~100W@4ohm amplifier is being able to push them to woofer seperation quite early, why would anyone even need more power than ~26V@8A other than with very exotic or very big tower speakers?
Holmz
Major Contributor
How do you go from 3.2 ohms to 1.6 ohms? Are you connecting two speakers to one channel?
Secondly the 3.2 ohms is probably DC resistance. But the speakers also have inductance, so that gets one towards 4 ohms with frequencies /= zero Hz.
In an active speaker, I am not sure you would need any external amplifier.
Johannesthalos
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No. My speakers go to 3.2ohm. The amp could in theory go down to 1.6ohm, but there is no speaker I know of other than subwoofers going that low. However, since it can go down this low means that there is plenty of headroom left in the base. Hence, I do not get the feeling of sound becoming "thin" on louder volumes as I probably (maybe) would get with a smaller amp running in BTL instead of PBTL. Running my amp in PBTL means it can do twice the current, but about the same or just slightly more Voltage. However, most of this power is wasted, since I will never plug a speaker to it that will demand such current. Nonetheless it is nice to have that headroom.
This is the active version of the LS50 Meta, it is called "LS 50 Wireless II" and it does have 1x200W D-Class and 1x80W AB-Class installed. Basically it is the same speaker just with an amplifier and a DAC with DSP installed. Therefore I figured the passive LS50 Meta could take similar or nearly similar power from an external amp.
OP
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Will do. Statistics though for the video shows it to have below average viewership. Maybe I have to find a clickbait title to go with them!
"Shocking video! See it here first!"
Will do. Statistics though for the video shows it to have below average viewership. Maybe I have to find a clickbait title to go with them!
Of course videos of “This $5000 cable doesn’t do anything!” videos would be watched more! People love mythbuster HiFi videos.
Raindog123
Major Contributor
1) To be dangerous to a human, a certain (a) level and (b) amount (duration) of _current_ needs to flow through critical internal organs (like heart and/or certain nerves).
2) Yes, due to a relatively high impedance of a human body (and of certain organs/parts — eg, skin — more than others) a _low-voltage_ electric source usually would not produce enough current to be dangerous/harmful (yes, per the basic Ohm’s Law). [However, under certain circumstances it can be — eg, electrodes directly attached to a heart, cuts in the skin, etc.)
3) However, a _high-voltage_ source might not always be dangerous either. It would depend on the amount (!) of the charge available at the source: If it is a “sustained“ (lasting) source of high voltage, then it is definitely dangerous and potentially fatal — as a high current will get generated to flow through the body’s internals. Yet, if it’s a [very] high voltage but a low capacity source, the quick (“transient”) discharge it can generate will only flow through the body surface due to (a) the “skin effect” (field distribution) and (b) capacitance and inductance of our body — irrelevant for sustained DC currents, but defining the electric charge distribution of a transient AC burst. [And this is why we can easily survive multi-kilovolt voltages of various “static” discharges, vandergraaf generators, and even lightnings — while with huge voltages, there is simply not enough charge to penetrate deep/long enough into the body to kill us…]
2) Yes, due to a relatively high impedance of a human body (and of certain organs/parts — eg, skin — more than others) a _low-voltage_ electric source usually would not produce enough current to be dangerous/harmful (yes, per the basic Ohm’s Law). [However, under certain circumstances it can be — eg, electrodes directly attached to a heart, cuts in the skin, etc.)
3) However, a _high-voltage_ source might not always be dangerous either. It would depend on the amount (!) of the charge available at the source: If it is a “sustained“ (lasting) source of high voltage, then it is definitely dangerous and potentially fatal — as a high current will get generated to flow through the body’s internals. Yet, if it’s a [very] high voltage but a low capacity source, the quick (“transient”) discharge it can generate will only flow through the body surface due to (a) the “skin effect” (field distribution) and (b) capacitance and inductance of our body — irrelevant for sustained DC currents, but defining the electric charge distribution of a transient AC burst. [And this is why we can easily survive multi-kilovolt voltages of various “static” discharges, vandergraaf generators, and even lightnings — while with huge voltages, there is simply not enough charge to penetrate deep/long enough into the body to kill us…]
Dear Amir,
I'd really like to know your opinion about the role of conductors on transferring energy based on the information below:
Could this be proof that may be it's not all snake oil with expensive cables or there's some science behind cable risers? Will the effect of conductance reflect in your measurements and thus is negligible?
I'll only be convinced if you're convinced
You have to distinguish between propagation speed of information (electromagnetic field along the wire) which is usually at 60% - 70% of speed of light and slow motion of electrons inside the conductor - conduction current of electrons.
Holmz
Major Contributor
Maybe just remove the cables and see if the energy transfers at all?
(That should give us an idea whether the conductors are playing a role or not.)
Franklin, Faraday and others, noted that the electric field is zero at the surface of the conductor. So the magic that was in that video, is stuff that has been known since Faraday and Maxwell, and is more physics based than something I would be trusting a cable manufacturer to be depended upon knowing.
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