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Drop Dan Clark Audio Aeon Closed X

aandres_gm

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I had my Drop order for a Topping A30 Pro amp cancelled yesterday: "...the item you ordered has become back-ordered, and we do not know if more inventory will become available. As we are unable to guarantee that we will receive this item, we have cancelled your order...". Rather shameful of them, I reckon, seeing as I have been waiting weeks, and it was supposed to be shipped this week! I only hope they manage to honour my order for Aeon X Closed (due March).

But, looking on the bright side, it gives me a chance to revisit my choice of amp. I had planned to go balanced, but only realized after ordering the A30 Pro that it isn't actually fully balanced, so I get a second chance in that respect!

The other big reason for chosing the A30 Pro was that it has oodles of power, as it seems the Aeon X Closed needs it, but I was never quite sure how much it actually needs to sing. I would be grateful for advice in this respect. Any suggestions for suitable amps would also be welcome.
What do you need the "fully balanced" for? I have a Topping _30 Pro stack that's running my Aeon Closed X beautifully. I can't get much further than 2 o'clock in low gain, even after applying EQ.
 

raistlin65

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The other big reason for chosing the A30 Pro was that it has oodles of power, as it seems the Aeon X Closed needs it, but I was never quite sure how much it actually needs to sing. I would be grateful for advice in this respect. Any suggestions for suitable amps would also be welcome.
Aeon Closed X don't need "oodles of power." They do need a good bit of current.

At 91dB/mW & 12.5 ohms, they only need 80mw


A JDS Labs Atom, Topping L30, or Schiit Heresy amp would work great with them. So unless you are determined to spend more for a balanced amp and for balanced cables, you don't need to spend that much.
 

hoverdonkey

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What do you need the "fully balanced" for? I have a Topping _30 Pro stack that's running my Aeon Closed X beautifully. I can't get much further than 2 o'clock in low gain, even after applying EQ.


Balanced has been recommended in various threads here, so I thought it would be worth trying. It does limit amp choice a lot though, so happy to forgo it, e.g. if the A30 Pro or others are a good match, thanks.
 

doug2761

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Balanced has been recommended in various threads here, so I thought it would be worth trying. It does limit amp choice a lot though, so happy to forgo it, e.g. if the A30 Pro or others are a good match, thanks.

From a reply that Amir posted in another thread:
" I want to make sure a distinction is made:

1. Balanced headphone connection has nothing to do with it being "balanced." All headphone connections are balanced since one end of your headphone is not connected to ground. Balanced option on a headphone amp can simply be thought of providing more power and that is it. If you don't need its extra power, you can use its 1/4 inch or 3.5mm output and be just as well.
"

I'm using a Drop THX AAA 789. With my Drop HD6xx, I can't hear a difference between the single ended and 4-pin, "balanced", headphone connections. Both are dead quiet and bot provide plenty of power to the headphones. I also have the Drop Aeon X and they work perfectly well with the 1/4 connection on the THX. The Drop THX AAA One or the others recommended above will be more than sufficient with the Aeon X.
 

hoverdonkey

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Aeon Closed X don't need "oodles of power." They do need a good bit of current.

At 91dB/mW & 12.5 ohms, they only need 80mw


A JDS Labs Atom, Topping L30, or Schiit Heresy amp would work great with them. So unless you are determined to spend more for a balanced amp and for balanced cables, you don't need to spend that much.
Oh dear, need to go back to my school physics books, I had equated current with power.

I already have a Topping D10b balanced DAC, so I should stick with balanced input at least.
 

hoverdonkey

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From a reply that Amir posted in another thread:
" I want to make sure a distinction is made:

1. Balanced headphone connection has nothing to do with it being "balanced." All headphone connections are balanced since one end of your headphone is not connected to ground. Balanced option on a headphone amp can simply be thought of providing more power and that is it. If you don't need its extra power, you can use its 1/4 inch or 3.5mm output and be just as well.
"

I'm using a Drop THX AAA 789. With my Drop HD6xx, I can't hear a difference between the single ended and 4-pin, "balanced", headphone connections. Both are dead quiet and bot provide plenty of power to the headphones. I also have the Drop Aeon X and they work perfectly well with the 1/4 connection on the THX. The Drop THX AAA One or the others recommended above will be more than sufficient with the Aeon X.
Many thanks, a very clear explanation, (wish I had seen that before!) and also for passing on your listening conclusions.
 

hoverdonkey

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Many thanks all for your combined masterclass.

I hereby vow to drop my quest for a "fully balanced" amp... and to do some homework following your teachings.
 

Morbosis

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Aeon Closed X don't need "oodles of power." They do need a good bit of current.

At 91dB/mW & 12.5 ohms, they only need 80mw


A JDS Labs Atom, Topping L30, or Schiit Heresy amp would work great with them. So unless you are determined to spend more for a balanced amp and for balanced cables, you don't need to spend that much.
Agreed My JDS Atom has no issue driving these. High gain at noon on the volume sounds perfect. Thought about "upgrading" but the more I listen the more I love my setup and realize its unnecessary.
 

JanesJr1

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Aeon Closed X don't need "oodles of power." They do need a good bit of current.

At 91dB/mW & 12.5 ohms, they only need 80mw


A JDS Labs Atom, Topping L30, or Schiit Heresy amp would work great with them. So unless you are determined to spend more for a balanced amp and for balanced cables, you don't need to spend that much.
Sorry for my lack of knowledge, but Amir's Aeon RT review shows a sensitivity of 677 mv to drive a 94 db spl. How would I use that to calculate current (= amps???) required using this headphone power calculator? And do headphone amps have amp ratings that define how much current they can handle? It would be very useful to help me apply Amir's rating to specific equipment.
 

raistlin65

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Sorry for my lack of knowledge, but Amir's Aeon RT review shows a sensitivity of 677 mv to drive a 94 db spl. How would I use that to calculate current (= amps???) required using this headphone power calculator? And do headphone amps have amp ratings that define how much current they can handle? It would be very useful to help me apply Amir's rating to specific equipment.

Sorry. I don't know how to do the math. That's why I use the headphone power calculator. So I look for sensitivity ratings to use it.

And headphone amps sometimes have current ratings. You have to look at the manufacturer specs. Be aware though that they are not always reliable. That's why most of us on ASR wouldn't buy a headphone amp that hasn't been independently tested.
 

JanesJr1

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Sorry. I don't know how to do the math. That's why I use the headphone power calculator. So I look for sensitivity ratings to use it.

And headphone amps sometimes have current ratings. You have to look at the manufacturer specs. Be aware though that they are not always reliable. That's why most of us on ASR wouldn't buy a headphone amp that hasn't been independently tested.
Thanks for the thoughtful response. The issue for me with the calculator is simply that I couldn't figure out how to input Amir's sensitivity figure ("677 mv required for 94 dbSPL") into the calculator's numerical format for sensitivity ("db(1mW)" or "db(1VRMS)"). I tried to figure it out from internet sources, but I lack the basic knowledge of electronics to do it. I tried restating mv and db variables in various ways, but when I input the number into the calculator, the result was nonsensical, so I'm obviously doing it wrong.

More generally, I see the comment about current vs. power often in these forum postings, but a specific measurement for current is almost never mentioned. It's also often hard to find a spec for, say, amperage in manufacturer spec sheets. We talk volts and milliwatts all over, but when it's current, it's just a comment to "make sure you get a high-current amp for this low-impedance headphone".
 

Robbo99999

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Thanks for the thoughtful response. The issue for me with the calculator is simply that I couldn't figure out how to input Amir's sensitivity figure ("677 mv required for 94 dbSPL") into the calculator's numerical format for sensitivity ("db(1mW)" or "db(1VRMS)"). I tried to figure it out from internet sources, but I lack the basic knowledge of electronics to do it. I tried restating mv and db variables in various ways, but when I input the number into the calculator, the result was nonsensical, so I'm obviously doing it wrong.

More generally, I see the comment about current vs. power often in these forum postings, but a specific measurement for current is almost never mentioned. It's also often hard to find a spec for, say, amperage in manufacturer spec sheets. We talk volts and milliwatts all over, but when it's current, it's just a comment to "make sure you get a high-current amp for this low-impedance headphone".
Amir hasn't measured this headphone yet (you mentioned his sensitivity figure). 1000mv = 1 Volt. But anyway, you'd use the specs for the Closed X from here:
and you'd plug them into a headphone calculator here:
and you'd get the following:
91dB SPL requires 1mw and 0.11 Volts and 8.9 millamps current:
DCA Aeon Closed X 90dB.jpg


94dB SPL requires 2mw and 0.16 Volts and 12.6 millamps current:
DCA Aeon Closed X 94dB.jpg



104dB SPL requires 20mw and 0.5 Volts and 40 millamps current:
DCA Aeon Closed X 104dB.jpg


114dB SPL requires 200mw and 1.58 Volts and 126 millamps current:
DCA Aeon Closed X 114dB.jpg


So that should give you an idea how to use the calculators and where/which numbers to input.
 

solderdude

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The issue for me with the calculator is simply that I couldn't figure out how to input Amir's sensitivity figure ("677 mv required for 94 dbSPL")

0.677V gives 94dB.
You want to know the sensitivity which is dB/V.
1/0.677 = 1.48
1.48(log) = 0.169 it is voltage so x20 = 3.4dB difference between 1V and 0.667V
We know 0.677 gives 94dB so 1V gives 94 + 3.4 = 97.4dB/V
with this handy calculator and the impedance you can calculate the efficiency (in dB/mW) = 78.4dB/mW

It would have been handy if the usual efficiency (dB/mW) and/or sensitivity (dB/V) specs were published instead of a voltage required to reach 94dB.
 
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Robbo99999

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0.677V gives 94dB.
You want to know the sensitivity which is dB/V.
1/0.677 = 1.48
1.48(log) = 0.169 it is voltage so x20 = 3.4dB difference between 1V and 0.667V
We know 0.677 gives 94dB so 1V gives 94 + 3.4 = 97.4dB/V
Although I think it should be pointed out (like I did in my post), that Amir hasn't measured this headphone yet, so this figure of 0.677V giving 94dB is fictitious for this headphone as far as I'm aware. Instead it's better to go off the manufacturing specs of 91dB/mw along with 12.5ohm, or until someone has measured the sensitivity of this headphone in a review or something.
EDIT: the 0.677V 94dB figure is from the Aeon RT review, yet this Closed X is a different headphone, but generally reported that it's just the pads that are different, but that could effect the SPL for any given frequency, so probably better to go off the manufacturers specs for the Closed X.
 

solderdude

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@JanesJr1 wanted to know the math for the headphone Amir measured (AEON closed RT) so I gave the math and the results of the math.

Read this on the Drop site regarding differences between Drop RT (measured by Amir) and Drop X:
I just confirmed with DCA that the RT and this set are indeed the same headphones

For some reason the efficiency numbers listed by Drop do not seem accurate. On top of that Dan doesn't give efficiency numbers. The difference seems to be the connector and supplied inserts.
 
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Robbo99999

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@JanesJr1 wanted to know the math for the headphone Amir measured (AEON closed RT) so I gave the math and the results of the math.

Read this on the Drop site regarding differences between Drop RT (measured by Amir) and Drop X:
I just confirmed with DCA that the RT and this set are indeed the same headphones

For some reason the efficiency numbers listed by Drop do not seem accurate. On top of that Dan doesn't give efficiency numbers. The difference seems to be the connector and supplied inserts.
This is the Aeon Closed X thread, not the Aeon RT thread, and it's already been established that they're different headphones even when a DCA rep said they were the same....that was months ago that this happened. Whatever, it doesn't matter, as long as people know.
 

solderdude

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There is a 12dB difference in efficiency between the Aeon Closed X and the Aeon RT closed ?
 

raistlin65

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0.677V gives 94dB.
You want to know the sensitivity which is dB/V.
1/0.677 = 1.48
1.48(log) = 0.169 it is voltage so x20 = 3.4dB difference between 1V and 0.667V
We know 0.677 gives 94dB so 1V gives 94 + 3.4 = 97.4dB/V
with this handy calculator and the impedance you can calculate the efficiency (in dB/mW) = 78.4dB/mW

It would have been handy if the usual efficiency (dB/mW) and/or sensitivity (dB/V) specs were published instead of a voltage required to reach 94dB.

Brent Butterworth's measured efficiency was notably higher than Amir's for the Aeon RT

"Sensitivity of the Æon RT Closeds, measured between 300Hz and 3kHz, using a 1mW signal calculated for 12.5 ohms rated impedance, is 85.9dB, which is pretty low, so you’re best off using a decent amp or portable music player with these, rather than a smartphone."


I wonder why the discrepancy?
 

solderdude

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I wonder why the discrepancy?

Could be the method. Could be someone made an error.
Amir measures at 400Hz which is not the same as between 300Hz and 3kHz.
The difference is 5dB.

Sometimes my measurements are 1 or 2 dB off from Amir's measurements which is mostly because look for average levels in the 300-2kHz range.
Never 5dB though.
 

Robbo99999

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There is a 12dB difference in efficiency between the Aeon Closed X and the Aeon RT closed ?
It is strange, I think people could maybe think it's somewhere between Aeon RT Amir measured sensitivity and Drop reported specs...people can decide where they think the Drop DCA Aeon Closed X will sit within that range until the Closed X has been measured in this sense.
 
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