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"These headphones/speakers sound better with more juice/current"??

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Hi, I'm trying to understand the following statement I hear quite often,

"These headphones/speakers sound better with more juice/current",

I read this again in a review regarding my latest acquired IEM's, so I thought to myself what does this mean exactly? currently I have a Mojo 2 and Qudelix 5K for mobile usage, I find being tied to usb using a Mojo 2 a little annoying so in many cases would prefer to use the Qudelix 5K, now if I want to improve the sound of said IEM's by providing them "more juice" what does that entail?

\/ Important part \/

Using the Qudelix 5K to power the IEMs from the single ended output rated @ 80mW to 32ohms, they get very loud at around 60% of of the volume providing 150mV of power, now the Mojo 2 is rated @ 600mW to 30ohms, now if I volume match Mojo 2 with the Qudelix, being that the Mojo 2 is a much more powerful amp is providing more "Juice/current" @ the same volume?

Today I was even testing out my HD6XX's with the Qudelix 5K, very comfortable listening levels @ around 80% of it's volume, around 400mV, it genuinely sounded very good, a/b with my Mojo @ the same volume I couldn't really tell much difference, but, if I was playing a quiet track that required me to max out the volume I noticed a difference, now I'm assuming because @ max volume I'm at the limit of the Qudelix 5K and it can't provide any more "Juice/current" when needed within a passage of a track, but as long as you have some headroom surely the performance using the Qudelix 5K should be the same as a higher powered amp at the same volume, is this correct?


What I want to try to understand is the importance of power, mainly low vs high and does it matter within reason?

I'm not sure if Amir has done a video on this but I think it would be an interesting topic to cover as I think it's very misunderstood.
 
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DVDdoug

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If you are not driving the amplifier into clipping (distortion) you don't need more power and there will be no difference with an amp that's capable of more power.

"Current" has a real definition and the units of measure are Amps or milliamps. "Juice" is just slang for electricity and it has no real definition or unit of measure.

Electrical power is measured in Watts and it's calculated as Wattage = Volts X Amps.

Ohm's Law defines the relationship between Voltage, Resistance, and Current (Current = Voltage / Resistance).

Resistance (and impedance) is the resistance to current flow.

Typically, voltage is "constant" (not really constant, but independent of the load) as long as everything is operated within it's normal operating range. So, current & power depend on impedance, and loudness depends on how efficiently the electrical power is converted to acoustic energy.

If you have low impedance headphones and the amplifier can't supply the "needed" current, the voltage be "limited" and the amp will clip at a lower voltage than with higher impedance headphones.

around 80% of it's volume
FYI - The position of the volume control doesn't tell you much... i.e. You can have a high-gain but low-power amplifier that's very loud at 10%. And of course the output also depends on the signal level being fed-in.

And a "standard" volume control potentiometer is not linear because our ears are not linear. At the mid-point the signal is something like 20% (I don't remember exactly). And that's a percentage of the maximum gain, not a percentage of the maximum output power.
 
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tiramisu

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Most people here won't suffer from this problem but I think the issue is that underpowered speakers don't sound as good.
By this I mean my umc404hd has a measured output of about 1.2Volts to the headphone amp. I have a pair of MDR-7506s.
When I plug into a headphone jack that provides the minimum spec 2Volts or better my headphone speakers get enough power to actually do what they are supposed to do.
Will more power make them better? I doubt it.

In the world of audio interfaces creating crap analog output is pretty much the standard.
If it is USB powered you don't have to ask. It is Garbage.

You need more power than USB provides to drive RCA, or headphones let alone balanced outputs.
 

solderdude

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Using the Qudelix 5K to power the IEMs from the single ended output rated @ 80mW to 32ohms, they get very loud at around 60% of of the volume providing 150mV of power, now the Mojo 2 is rated @ 600mW to 30ohms, now if I volume match Mojo 2 with the Qudelix, being that the Mojo 2 is a much more powerful amp is providing more "Juice/current" @ the same volume?

Nope, they will be supplying the exact same power when playing at the same volume (providing both can reach that level without clipping)
It does not matter to the sound if one can play 10x as loud as the other one. It only starts to matter from the point where the one with the least output power starts to clip.

Today I was even testing out my HD6XX's with the Qudelix 5K, very comfortable listening levels @ around 80% of it's volume, around 400mV, it genuinely sounded very good, a/b with my Mojo @ the same volume I couldn't really tell much difference, but, if I was playing a quiet track that required me to max out the volume I noticed a difference, now I'm assuming because @ max volume I'm at the limit of the Qudelix 5K and it can't provide any more "Juice/current" when needed within a passage of a track, but as long as you have some headroom surely the performance using the Qudelix 5K should be the same as a higher powered amp at the same volume, is this correct?

The HD6XX does not require much power, it does require a higher output voltage when you want to play loud.
Qudelix 5k can supply 7V (TRS) and 14V (balanced) which is more than enough for the HD6XX
Mojo 2 can supply 4.6V so the Qudelix can play louder.
Up to 4.6V both will be equally loud and sound the same.
 

Jimbob54

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Did you mix something up? The 5K does 4Vrms via 2.5mm, 2Vrms via 3.5mm.

Smells a bit fishy to me. The bird has been at the sauce.

Regurgitated herring juice anyone?
 

JanesJr1

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Most people here won't suffer from this problem but I think the issue is that underpowered speakers don't sound as good.
By this I mean my umc404hd has a measured output of about 1.2Volts to the headphone amp. I have a pair of MDR-7506s.
When I plug into a headphone jack that provides the minimum spec 2Volts or better my headphone speakers get enough power to actually do what they are supposed to do.
Will more power make them better? I doubt it.

In the world of audio interfaces creating crap analog output is pretty much the standard.
If it is USB powered you don't have to ask. It is Garbage.

You need more power than USB provides to drive RCA, or headphones let alone balanced outputs.
As a practical matter, there are USB dongles that can drive even current-hungry DCA headphones, much less HD6XX's (I own both). I use both Hidizs S9 Pro and E1DA 9038s G3 dongles to drive two sets of DCA phones, in balanced mode. They sound identical to being connected instead to my reasonably-powerful desktop Topping amp (although max SPL is lower, but still plenty loud enough). I believe the Qudelix 5k can also drive the DCA phones, battery notwithstanding (though I haven't used it myself).

As long as the headphones are not clipping, there's a strong school of thought that more power doesn't improve sound quality, it just raises the maximum SPL. That's my experience so far with 3 headphones, two amps and four dongles (leaving aside IEM's). I still read published reviews that go on about how big-power can improve the dynamics and low-frequency extension of headphones, but I have yet to experience it. I'd be curious if there is an authoritative contrary case.
 

ZolaIII

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I think you got it wrong. Impedance of an analog transponder is not static, it varies trogh frequency range. With those that have huge jumps in the hot areas of the signal (mainly bass and mids) you will need a lot more voltage then averaged or declared. That's all what there is to it. You want amplifier for it to be in the amplification range where it behaves and mesure best (usually close to the top of the stage used in pretty much all modern one's). Now you see how people get miscalculated and create problems for them self and why you hear it a lot.
 
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staticV3

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Impedance of an analog transponder is not static, it varies trogh frequency range. With those that have huge jumps in the hot areas of the signal (mainly bass and mids) you will need a lot more current then averaged or declared.
Why would an increase in impedance lead to more current? Doesn't that go against Ohm's law?
 

ZolaIII

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Why would an increase in impedance lead to more current? Doesn't that go against Ohm's law?
You must be joking right? Higher the impedance you need more power or current if you wish (W/V).
 

staticV3

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No why would I drive a headphone using line out? It's not made for driving headphones.
 

staticV3

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@ZolaIII let's say we play a bass line with 50Hz and 100Hz tones at equal amplitudes on an HD650. And the Amp is set up so that the tones play at 0.5Vrms. Plausible?
Sennheiser HD650 Measurements Impedance.png
At 50Hz the Amp will output 0.5^2/385≈0.65mW RMS / 1.30mA RMS
At 100Hz the Amp will output 0.5^2/480≈0.52mW RMS / 1.04mA RMS

->higher impedance means less current means less power at a given voltage

I'd appreciate if you could point out my misconception here and why an increase in impedance will instead result in higher current and power from the Amp.
 

ZolaIII

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May be that looks as a big variation for you but it's not. In speakers let's say even declared 6 Ohm's you can have spikes over 50 Ohm's (8.3x more than declared) and if it's in a area that is widely used (hot) it will need (much) higher average V to drive them then declared. V goes up and A goes down as you said.
You got a saying wrong in the first place (they didn't mean A strength but V).
V*A=W
Of course lo impedance loads and deaps under 3 Ohm's in speakers represents opposite problem of high A that can burn things up with systems that aren't tolerable to such (usually one of protection circuits or a fuse would kick in /burn) or burning cables which can't sustain such A at given V.
 
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staticV3

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V goes up and A goes down as you said.
? No I did not say that. Voltage stays constant in my examples, just like a headphone amplifier would act when driving an HD650. Constant voltage at both the driver's lowest and highest impedance.
You got a saying wrong in the first place (they didn't mean A straight but V).
V*A=W
I don't understand. What did I get wrong? Who is they?
V=I*R is 100% Ohm's law.
 

ZolaIII

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"These headphones/speakers sound better with more juice/current",
they mean more power (more Voltage regarding amplifier not really strength of current). Tolerance to lo loads (very lo loads for such) is also problem for some serious hedaphone amplifiers that have high V (again relatively speaking) output.
 

Cars-N-Cans

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What I want to try to understand is the importance of power, mainly low vs high and does it matter within reason?

I'm not sure if Amir has done a video on this but I think it would be an interesting topic to cover as I think it's very misunderstood.
The maximum SPL level an amplifier can get with a certain headphone will impact how you perceive the tonality. This is why things like the “loudness wars” existed. Louder is generally perceived in a positive light as the perceived spectra flattens out due to how our hearing works and the headphone will sound “fuller” at higher volume levels. I have run into this with amps that could not provide sufficient drive to the headphones. The “difference” disappears as soon as both amps are level matched and provide the same output.
 

Cars-N-Cans

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Amir has done videos that touch on the subjective reasons a difference is heard. Have a look at his “How Loud is Loud“, ” Understanding Audio Frequency Response and Psychoacoustics”, and “Reviewing Speakers - Measurements and Listening Tests”. The topic of level matching and it’s impacts are discussed.

Now this ignores things like respective noise floors, clipping, distortion, etc but almost always it’s a subjective issue of differing volume levels for each respective device if one amp can’t provide as much drive for a headphone before the amp starts to clip.
 

solderdude

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Did you mix something up? The 5K does 4Vrms via 2.5mm, 2Vrms via 3.5mm.

yes my bad... 2.6V (forgot to SQRT the calculated 6.9V :() in TRS and thus is double that, so 5.2V in balanced.
Mojo 2 can supply 4.6V (but only has TRS out) so the Qudelix can play 1dB louder in balanced mode but in SE mode the Mojo2 is 5dB 'louder'.
Based on Amirs measurements.

You must be joking right? Higher the impedance you need more power or current if you wish (W/V).

Nope Static V3 is right.
The higher the impedance the higher the required voltage is but the lower the current.

To reach 1W in 300Ω you need 17.3V and draws 57mA
To reach the same 1W in 16Ω you need 4V and draws 250mA

Both the same power but higher imp requires a higher voltage but lower current.

Now... I get where your confusion comes from which is from the fact that amplifiers are voltage sources and not power sources.

To reach 1W in 16Ω you need an amp that can reach 4V but that same amp can only 53mW in a 300Ω headphone.
To reach 1W in 300Ω you need an amp that can reach 17.3V but that same amp (assuming current requirements are sufficient) can reach 18.7W in 16Ω.

So following that idea to reach a higher SPL in high impedance headphones (assuming efficiency is the same but sensitivity is not due to different impedance) it appears as if you need an amp that must be able to supply a higher power (in 16ohm only) in order to get them to play equally loud.
So that higher power (actually voltage) amp can drive both low and high impedance headphones to the same SPL (but at different volpot or gain settings) but the lower power amp (in 16ohm only) can not make the higher impedance headphone reach the same SPL.

To complicate things a bit more...

It is quite easy to construct an amp that can reach 17.3V but has a current limiter at 250mA.
That amp can thus provide 1W in 300Ω but can also reach 1W in 16Ω

In fact, one can even construct an amp that can deliver 17.3V with an current limit at 60mA
That particular design (OTL tube amps for instance or opamp output circuits with a 85mA current limit) can provide 1W in 300Ω but merely 58mW in 16Ω.
So that amp can thus provide more power in high impedance headphones than it can in low impedance headphones.

This means one should not talk about power delivery in amplifiers unless the impedance is also taken into the equation.
 
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