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Topping A30Pro Review (Balanced Headphone Amp)

Ahmonge

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Could this voltage and sensitivity mismatch just be fixed with the EQ APO preamp?
The difference between 4V and 2.7V should be 20•log(2.7/4)= -3.4dB
Not in my case; I run Qobuz on iOS as a source > USB > D30 Pro
 

usern

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Thanks a lot for your answer. But i’m not concerned with overall clipping, but clipping the input stage (before gain and volume controls) due to the mismatch between max output voltage of the D30 balanced output (4 Vrms) and the A30 Pro 2,7 Vrms balanced input sensitivity. If this sort of clipping happens, I would hear distorted sound no matter the which gain and volume set.
Do you experience problems when playing -0dB signal from D30pro?

Check these posts by Topping electronics designer:
 

Ahmonge

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Do you experience problems when playing -0dB signal from D30pro?

Check these posts by Topping electronics designer:
First of all, thanks for your detailed answer.

On some songs I have heard a slight distortion in the bass, and I am trying to discern if it is a problem of the record or saturation in the input stage of the amplifier when I connect it to the DAC via XLR. It is clear to me that I do not reach the amplifier maximum power, because I hear below 80 dB on average with the Aeon Noire (93 dB/mW at 13 Ohms impedance).

Unfortunately, the designer’s answers are not specifically directed to my queston.
 

usern

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On some songs I have heard a slight distortion in the bass
What headphone and what volume level? Or is it constant at any volume? Is it with all bass content or just one file / music track? Can you give a youtube example where you hear this distortion from that youtube video?
 

NiagaraPete

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What headphone and what volume level? Or is it constant at any volume? Is it with all bass content or just one file / music track? Can you give a youtube example where you hear this distortion from that youtube video?
YouTube is not a quality source.
 

Ahmonge

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What headphone and what volume level? Or is it constant at any volume? Is it with all bass content or just one file / music track? Can you give a youtube example where you hear this distortion from that youtube video?
Only with some tracks mastered at high volume, only with the bass part of them, no matter the volume I’m listening to them (which is always below 80 dB average with the Aeon 2 Noires)
For instance: Madeleine Peyroux, Careless Love, track #2 Dont Wait Too Long (Qobuz version)
 

usern

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Yes, we agree.
Youtube quality does not matter. If I could hear your source, then we can determine if it's actually source file problem, not DAC / AMP problem. If it's the problem you describe it to be, then the distortion should go away when lowering volume in software (windows volume slider or music app volume slider).
 

Ahmonge

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Youtube quality does not matter. If I could hear your source, then we can determine if it's actually source file problem, not DAC / AMP problem. If it's the problem you describe it to be, then the distortion should go away when lowering volume in software (windows volume slider or music app volume slider).

That's Youtube version of this track. On this version I don't hear the distortion, but I do on both the Qobuz version and the ripped version of the CD. I am inclined to think that, in this case, the cause is the recording, because I have played the same effect on other equipment (PC > Foobar2000 > Asio Driver > USB > Fiio K5 Pro > Aeon 2 Noires).

I followed your instructions. If I lower the volume on the Foobar 2000 and compensate with the volume of the K5 Pro, the distortion is still present. Thanks for your advice!
 

roundsound

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I have recently received a pair of Aeon Noires and I am thinking about upgrading my amplifier. I currently have an old O2 amp. I don't need pre-amplifier functionality and I am not convinced that I need balanced output with the kind of single-ended power available from a amplifier like the A30 Pro. It seems the main area of possible improvement for the A30 Pro is channel balance. Does a single-ended amplifier as powerful as A30 Pro but with resistor ladder volume control exist? Perhaps the next iteration of A30 might have this...
 

juliangst

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I have recently received a pair of Aeon Noires and I am thinking about upgrading my amplifier. I currently have an old O2 amp. I don't need pre-amplifier functionality and I am not convinced that I need balanced output with the kind of single-ended power available from a amplifier like the A30 Pro. It seems the main area of possible improvement for the A30 Pro is channel balance. Does a single-ended amplifier as powerful as A30 Pro but with resistor ladder volume control exist? Perhaps the next iteration of A30 might have this...
I have the A30 Pro and the Noires are my daily drivers. There is absolutely not problem with channel balance. The only problem is power.

I often run my Aeon Noires at 3 o'clock with more quiet classical music. I think if I had the choice again I would safe up and go for the A90d.
Like so many other amps, the A30 is current limited at such low impedances like the 13 Ohm Noires.
 

Ahmonge

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I have the A30 Pro and the Noires are my daily drivers. There is absolutely not problem with channel balance. The only problem is power.
Well, I have the same amp and headphones, running them at medium gain (0 dB), no channel imbalance, 12 to 1 o’clock for rock, 1 to 3 for classical. Still 14 dB reserve if I switch to high gain, so plenty of reserve power available.
 

usern

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I also had Noires briefly and I would not say A30pro lacked power. @juliangst do you use RCA or XLR inputs? What gain setting? Perhaps the source PC or device has attenuated volume setting?
 

juliangst

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I also had Noires briefly and I would not say A30pro lacked power. @juliangst do you use RCA or XLR inputs? What gain setting?
All my listening with the Noire is at high gain.

Currently using RCA from my SMSL Sanskrit but I'll soon get the Moondrop Dawn for a balanced connection.
The A30 Pro has a max input sensitivity of 2.7V. Comparing my 2V DAC to a 2.7V input would result in 2.6dB difference, so the difference in input voltage isn't really responsible for too low volume.

L7audiolab's measurements show that the A30 Pro has roughly 4.6V at 8 Ohms (which is the more representative value than a 16 ohm voltage here),
so the Aeons will get roughly 1.6W.
Given that they're not the most sensitive cans either it's not that surprising that my A30 Pro can't drive them to damagingly loud levels with more quiet classical music
 

usern

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What about modern music which is more compressed / normalized, does it sound too quiet also?
 

Ahmonge

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L7audiolab's measurements show that the A30 Pro has roughly 4.6V at 8 Ohms (which is the more representative value than a 16 ohm voltage here),
Noires have 13 Ohms impedance, so 16 Ohms figure is closer to reality than 8.
 

juliangst

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What about modern music which is more compressed / normalized, does it sound too quiet also?
Modern pop music is fine. But if I listen with replay gain it can be too quiet sometimes as well
 

juliangst

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Noires have 13 Ohms impedance, so 16 Ohms figure is closer to reality than 8.
Most amps have a significant drop in voltage after 16 ohms so 8 is more representative.
I wish Amir did 12 ohm measurements before.
This smsl amp‘s measurement for example shows that voltage drop:
index.php


The new Topping L70 also begins to drop a lot in voltage with low impedance loads:

1666804354-BAL-THDN-Ratio-vs-Measured-Level-2.jpg
 

Ahmonge

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2,7 W at 8 ohms gives us an amperage of 0,58 amps, which is the factor that limit the power at such low impedance. At 16 ohms we get 6 W, so an amperage of 0,61 Amps, so we can assume the worst case (0,58) for 13 Ohms, so we get 4,37 Watts.
 

juliangst

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Finally got the Moondrop Dawn with a dual 3-pin XLR to 4.4 cable as a permanent DAC for the A30 Pro
My Aeon noires now get a lot louder and reach really loud levels at around 11-12 o'clock (had to push them to 3 o'clock before).

I've also set -1dB in EqApo because multitone tests show really high IMD at 0dbfs. The dongle alone obviously can't power my Aeons and clips at ~80% iPad volume

I've hidden it in my cable tray which makes my desk look a lot tidier :)
 
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