[proton007]

Hi all, 
I regularly keep reading this term: Juice.
The usage as I can see in the forums is varied, comments like
 
Quote:

some amps can "supply more juice"

 
or,
 
Quote:

how to make my headphones sound "better with extra juice"

 
So I put forth this question, what is this juice? 
Is there any scientific meaning to it? Or is it just a hypothetical concept?

 

[mikeaj]

Likewise:  power.  I think those terms are used roughly interchangeably.
 
I'm pretty sure that the majority of times you see the word "power" on these forums, you shouldn't interpret that as actual (electrical) power.  They mean something else.  Then somebody goes out and gets a powerful (meaning electrical power) amp capable of 5W power output, to drive sensitive headphones that need closer to 1mW to 50mW to be excruciatingly loud, hoping for a more "powerful" sound.

 

[proton007]

Yeah, I also don't seem to agree with the "power" term as well. A headphone needs the same amount of electrical power to produce sound at a particular SPL, regardless of whether you have an amp that can supply 5x that power or 10x. In fact I think there can be considerable damage in overdriving the speakers/headphones.

 

[proton007]

I just feel its a manifestation of this desire to have your device perform better, something that is actually governed by the limitations of the product design.

 

[Magick Man]

Okay, take my LD I+ as an example. It puts out 500mW @50Ohms, according to the manufacturer. It will drive my HE-6s to a good volume and they sound okay, however the amp doesn't put out enough voltage to truly extend and fill out the bass on them the way it should be. It isn't that the bass sounds particularly muddy or poor, part of it is just missing, so it sounds lighter. But hey, what do you expect from a $110 amp?

 

[proton007]

Quote:

Okay, take my LD I+ as an example. It puts out 500mW @50Ohms, according to the manufacturer. It will drive my HE-6s to a good volume and they sound okay, however the amp doesn't put out enough voltage to truly extend and fill out the bass on them the way it should be. It isn't that the bass sounds particularly muddy or poor, part of it is just missing, so it sounds lighter. But hey, what do you expect from a $110 amp?

 
I think it also has to do with the 83.5 dB/mW sensitivity...It would require >500mW to hit 110dB peaks, most amps would struggle.

 

[Magick Man]

83.5 dB/mW is probably a little exaggerated, in my experience. I would bet it's really high 70s.

 

[obobskivich]

Fairly sure "juice" means "power" - as in P= V*I.

Regarding the HE-6:

InnerFidelity measured them at 20 mW/90 dB ->1.25 mW/78 dB. Too lazy to take that quarter off. Makes me want to agree with 83.5 being optimistic.

Anywho, I agree with:

"I just feel its a manifestation of this desire to have your device perform better, something that is actually governed by the limitations of the product design." and would add:

In some cases a person gets an item, it's incompatible with or performs poorly with their existing items, so they over-buy to compensate, and feel that over-purchasing was the "only answer" to the problem. I've seen this pan out a time or two in context of "juice" (you have a headphone that's relatively or blatantly inefficient, like the K701, HE-6, K1000, etc and someone tries to run it with something silly and it flops, so they run out and buy something HUGE in response to positive reviews/hype, and then champion that HUGE purchase as the only viable solution). While it doesn't result in bad advice, per se, it can build up a dragon when one doesn't need to exist.

 

[ProtegeManiac]

I usually mean "current" or "voltage" than "power" in general when I use the term. Either way the usage of "juice" to refer to these, as best I'm aware of, comes mostly from American English. Observe how in some media (movie, comics, cartoon, etc etc) they use "juice" to mean electricity, or most often specifically an electric shock, and "fry/fried" to refer to the biological entity (usually a person; victim, bad guy, etc) who was about to/is getting/got shocked, the same way "crank (it up)" (like the Jason Statham movie) usually means to increase the gain or volume, voltage, etc.

 

[Steve Eddy]

I think "juice" is a great euphemism for current as they both "flow," and it is after all the current flowing through the voice coils which produces the magnetic field that drives them. Of course all else being equal in order to get more current you need more voltage which ultimately means more power so it's all related (Ohm's Law tells us that).
 
se

 

[proton007]

Thanks for the replies. 

So am I right in saying that if you make an informed purchase, by checking out your headphone power needs before buying your amp, you can prevent this issue of over compensation? After all, a headphone will take the juice it needs if an amp can supply it.

 

[obobskivich]

Thanks for the replies. 
So am I right in saying that if you make an informed purchase, by checking out your headphone power needs before buying your amp, you can prevent this issue of over compensation? After all, a headphone will take the juice it needs if an amp can supply it.

I think you could just stop with "make an informed purchase" - unfortunately I think a lot of people don't even make it to that step. The only serendipitous purchase I've ever made in audio was my MDR-F1s, and it was a total shot in the dark. Everything else has either been well thought out/planned and turned out as intended, or has been a complete shot in the dark and ends up in a constant cycle of "upgrade and replace" to slowly chip away at getting it done "right." (Usually for more money or with more headache too!).

That's just my experience, ymmv.

 

[Chris J]

S = P + jQ

 

[Mauricio]

Complex power, yes.  Complex power is a concept that takes into account the impact of frequency on the phase difference between voltage and current.  The effective power is proportional to the phase difference between current and voltage.

 

[Chris J]

Complex power, yes.  Complex power is a concept that takes into account the impact of frequency on the phase difference between voltage and current.  The effective power is proportional to the phase difference between current and voltage.

I really just put that in there as a goof!

I would guess that 97% of the head fi-ers have no idea what we are on about!

Normally I think of Orange Juice when I think of Juice!