[Jalo]

It doesn't equal to any of that - since the official spec is 12 Vrms into no load (per AK tradition, none of their output power spec has load attached). You cannot derive the other numbers by swapping the resistance number when the original spec gives no load condition which is literally a divide by zero error.

No one will know AK player's number unless they actually measure it with a load attached - AK's official spec had and still is absolutely useless yet people just keeps repeating it.

“Condition No Load” Is a number and a known variable just like Zero is a number. When the resistance is known as in Ohm then you can convert it into wattage. Because of my interest in the Khan Cube I wanted to know exactly how much power (12Vrms) are we talking about, I specifically consulted an electrical engineer from IIT, those were the numbers we came up with under different loaded conditions. Remember from no load which is zero to different loading like 30 ohm or 60 ohm is a known linear variable that can be used in the conversion. I will post the formula for that conversion when I return home later today.

As for the unit measurement of root means square (RMS) it refers to the measurement of constant and sustained power supply as oppose to the common term of maximum milliwatt per channel that is based on peak to peak calculation. So 250 milliwatt per channel may actually mean that the channel is capable of reaching up to 250 mW even for a split second but in actuality it may be running only 200 mW on a constant basis. On the contrary, when root means square is used as a measurement, it is only talking about average power supply for a given channel, it is not talking about maximum capability and in fact for any root mean square you can add a factor of 0.719 to the measurement representing headroom or swing for that channel. Let say for instance a 6 Vrms into 30 ohm will give 1.2 watt of average driving power, but in times of need for dynamic swing like when the cannon in 1812 concerto kicks in, it can go up to 1.7 watt as maximum power with an additional factor of 0.719.

 

[Jalo]

So the formula for converting Vrms into wattage is as follows:

Power output in Wattage = (Vrms)(Vrms)/R where R is resistant in Ohm. So let say an amp output is 6 Vrms and it is driving a 36 ohm headphone, then 6 Vrms squared is 36 divided by the resistance of 36 ohm, the power output in Wattage is 1 watt.

Then to convert the average power output into peak or maximum output, using the above sample, you would divide the 1 Watt by a factor of 0.7071 and the peak output of this amp is 1.41Watt. The factor 0.7071 is a technical definition for converting average output into peak output.

 

[markt1600]

DMP-Z1 isn’t thin sounding, especially with MDR Z1R. But thanks for the respond

Want to echo this as I found the DMP-Z1 to very much possess Sony's "house" sound which leans towards warmth. Have been listening to the Z1 fairly extensively over the last month or so and have come to better understand its sound signature in ways that I wasn't able to appreciate during in store or CanJam listening.

First, have realized that the balanced out is far superior to the unbalanced out and think that if you have a choice, there's no reason to use the unbalanced out (which also only outputs 1/3 the power).

Second, the DMP-Z1 excels in its imperceptible noise floor and dynamic range - both of these take a quiet listening environment to observe but you are richly rewarded in detail. Hearing music go from blackness to full orchestral swing, or feeling the slam of hip-hop, is where the Z1 is truly able to shine.

Let's face it - at this price point, the differences are extremely subtle and there is no bang for the buck. But when you are listening for the details, the Z1 provides them.

 

[nanaholic]

@Jalo

I know exactly how you come up with the numbers, but you are applying the equations wrongly.

There are multiple websites which has the conversion formulas programmed in and you can check them easily, such as these below:
https://www.analog.com/designtools/ru/toolbox/dbconvert
https://owenduffy.net/calc/voltcnv.htm

The numbers you came up with is only you holding Vrms constant while changing the resistance value - but that is WRONG and not how the circuit and the application of the formula works.

To show this let's take Chord Hugo 2's specs, which they handily provide three values:
94mW @ 300ohms
740mW @ 32ohms
1050mW @ 8ohms

If you plug in the numbers you get Vrms values as follows:
300ohms > 5.31Vrms
32ohms > 4.866Vrms
8ohms > 2.898Vrms

As you can clearly see, the Vrms values fluctuates GREATLY depending on the load being attached. This is why you cannot hold the assumption that 12Vrms under no load means it is 12Vrms for every other resistance value you then attach to it. And this is why your numbers are not just wrong, but MASSIVELY wrong.

Also for fun please try 12Vrms @ 0ohms (ie no load), note how it throws errors... because as I said - it's a divide by zero equation. No load means infinite amount of current just by simply applying Ohm's Law, and since power equals voltage x current, if you have infinite current it means you have infinite power... see how this doesn't work?

To see some more let's have a look at how AK's previous flagship measures up:
https://www.avhub.com.au/product-re...-ak380-portable-music-playerdac-review-414055

These's guys had measured the AK380 output (unbalance and balance for AK380 is supposedly 2.1Vrms unbalanced and 2.3Vrms balanced no load) with 50mW @ 32ohms. Again if you plug the numbers in the Vrms at this level is 1.265 - way off from the 2.1Vrms no load condition.

You also have these guys measuring the AK300 series amp's balanced output:
https://reference-audio-analyzer.pr...hp?id=1498&page=amp-astell-kern-ak380-amp-bal
In the high gain mode you have 94.48mW into 32ohms, and 11.29mW into 300ohms. Converted this gives 1.7Vrms and 1.84Vrms respectively - again FAR from the 8Vrms no load condition as specified officially.

To get a useful data point you must have the power output as well as a normal load attached before you can apply the Vrms to mw conversion. A Vrms no load condition simply cannot be used to infer the other power output levels.

Ohm laws is a laws isn’t it ? Doesn’t matter what language you speak, the DMP-Z1 is not as powerful as it appear, a hybrid desktop-Portable Device. Especially when compared to KANN Cube

That is not the point and is irrelevant to the DMP-Z1. The point is that Jalo is applying the Ohm Law wrongly and that AK's numbers are actually meaningless.

AK is the only manufacturer who publish output power with no load - every single other manufacturer at least specify one (or multiple) load conditions. People need to call AK out on this misleading marketing approach.

 

[Jalo]

@nanaholic, I appreciate your raising the issue of application of the formula, I guess our differences lie with the concept of constant. Generally speaking, If one just look at a formula with three variables, it is true That if two of the three variables are known then the value of the third variable can be known. It is also true that by varying any two variables you can change the value of the third variable. And that is what you did with the application of the formula above by plunging in two of the three variables thereby changing the value of the Vrms and what you did is accurate in general terms except the following:

Let me prefaced it by saying I am not a fan boy of AK and I do not have any inside connections with AK to know what those published value means other than what is being published on their website. I actually own two WM1Z, one WM1A and the Z1R to give you some perspective and I do not feel any urge to defend AK at all. My only interest is to understand and get good sound.

Having said that, when I read “12 Vrms, Condition No Load” to me it simply means that is the value of the device, Khan, AK 380 or whatever the device happens to be by circuitry design without any load. So to me of the three variables:

A. Vrms of the device by circuitry design
B. Resistance in Ohm
C. Output power in Wattage

One can vary variable B by changing headphones with different impedance value, one can also change Valuable C for any amount a person wants or desires by varying valuable A and B. What we cannot change is the circuitry by design inside the Khan, AK380, SP1000 etc. that produce the Vrms under no load condition hence I hold variable A (Vrms) constant. Without assuming variable A is constant you are correct by varying B and C variable A (Vrms) has to be different. I will be happy to agree with you if my assumption that the stated Vrms is not derived by hardware design. But if the Vrms value is produce by hardware design then one must hold it constant and my application of the formula is accurate. I can only assume that the volt root mean square (Vrms) is a value produced by the amplifier circuitry otherwise what else could have generate the power in a dap if not for the hardware and that is why you cannot reverse the formula to come up with different Vrms because we cannot alter the hardware inside the circuitry.

Those websites that you cited for power calculations is accurate but they do not know or take the assumption that one of the Variable cannot be varied.

 

[jonstatt]

By the way, for those who happen to receive a gift of DMP Z1 from Japan (very lucky you) or for those who can't wait to get the official version in their country and ended up buying one in Japan (that's me), there is a way to change the language from Japanese to one of your liking. The nice developer at rockbox.org has updated their dest tool program to recognize DMP Z1. I used it successfully by choosing dest E and SPS off. Here's the page where you can find the tool: https://www.rockbox.org/wiki/SonyNWDestTool#Getting_the_tool

Thank you pamaury.

This means they put a volume cap on the EU version for a device like this? I really wonder why Sony needs to do this when other manufacturers don’t seem to

 

[nanaholic]

@nanaholic
Those websites that you cited for power calculations is accurate but they do not know or take the assumption that one of the Variable cannot be varied.

That's because that is the correct assumption those websites are making.

You are assuming that either the current or voltage (Vrms) is going to be constant when changing the resistant yet in the real world there is NO linear relationship between the three variables - as demonstrated by the real world Chord Hugo 2 numbers and the AK device measurements. A linear relationship with a variable load is only possible in an ideal circuit, which none of the real world devices are. In reality the relationship of the load vs power for all these devices are actually highly non-linear. This is why all your calculations are wrong and your assumption about the KANN Cube outputs are wrong because we know for sure that these devices cannot produce a perfectly linear relationship between the 3 variables (the AK devices even has a massive dropoff in power output when a low impedance load is attach). Your wall of text doesn't explain anything at all.

 

[Whitigir]

Woa...I didn’t know there are 5x super-capacitors inside the DMP-Z1. Here are some FCC pictures
https://fccid.io/AK8DMPZ1/Internal-Photos/04-Internal-Photo-4022515

 

[skr3328]

My unit just arrived and I really like its compact design and mobility. It is a desktop device that I can carry to the office or bedroom. Great!

Or I can carry it on metro? just kidding

 

[Whitigir]

I like that Belt style....but why black out your face ? . It will need a long time burning in ! Enjoy !

 

[jonstatt]

I don’t like the fact that the black glossy sections are not glass. It is the type of finish that scratches just by looking at it wrongly

 

[Whitigir]

I don’t like the fact that the black glossy sections are not glass. It is the type of finish that scratches just by looking at it wrongly

Lol, is that so ? How about some plastic wrapping like car windows tints?

 

[Audiophile2019]

My unit just arrived and I really like its compact design and mobility. It is a desktop device that I can carry to the office or bedroom. Great!




Or I can carry it on metro? just kidding

I really envy you, bro..

 

[skr3328]

I like that Belt style....but why black out your face ? . It will need a long time burning in ! Enjoy !

I got this used unit(only 35 hrs running time) for 5500 usd and I think it is quite a good deal. Now I have sold all my dap dac and amp. Z1 killed all my desire on upgrading audio stuff.

 

[Whitigir]

I got this used unit(only 35 hrs running time) for 5500 usd and I think it is quite a good deal. Now I have sold all my dap dac and amp. Z1 killed all my desire on upgrading audio stuff.

That is awesome deal! Congratulation