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Review and Measurements of Aune X7s and Arcam rHead Headphone Amps

sssn

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The Aune X7s is a chinese desktop-sized headphone amp..of course it has 10 ohm output impedance. I'm 100% sure it's based on the TPA6120A2, like all other chinese desktop amps.
 

Jimmy

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I thought the same, but looking at the pcb it seems to use transistors (probably mosfets), anyway to be sure it would be necessary to remove the large heatsink covering these components.

Anyway, in my opinion the price is a bit on the high side for what it offers.
 

dc655321

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Amir is it possible for You to measure the output impedance of line out of X7S. I am curios if it is lower then 10 ohm closer to 2 ohm will I be able to feed signal into a external volume control and use that output for lower impedance headphones. Thanks.

Topping's spec sheet for the X7S lists 100 Ohms for the RCA outs and 200 Ohms for the XLR outs.
This is typical - line outs are not intended to interface with headphones, but rather high input impedance sinks (amps, etc).
 

helloworld

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I like the look of those Aune X7s measurements. It has even lower distortion than my Topping A30. Although it is $300 on Amazon, so it costs more than my DAC and amp combined.
If you can get it from China, it’s actually $150
 

Bhargu

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Okay, so there was this in the RME review, on the impact of output impedance on headphone thd+n
https://www.audiosciencereview.com/...ments-of-rme-adi-2-dac.2582/page-5#post-74090

And solderdude's thoughts on why damping factor is overrated
https://www.audiosciencereview.com/...tions-he-560-and-hd6xx.3840/page-3#post-91954

I always assumed people were talking about the voltage divider effect when they talk about damping factor. My assumption was because people always talk about the impedance curve and the change in frequency response wrt. damping factor. That is not an effect of damping factor, but that of a voltage divider.
 

mindbomb

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Yea, the voltage divider frequency response problem doesn't really bother me, since you can choose high impedance headphones or planar magnetic headphones to avoid it. I'm more concerned about the increased distortion from the lower damping factor.
 

Anaz

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Hi, great review. I use an Arcam rHead with in iFi iPower - am I correct in concluding that the mains hum should be reduced (or eliminated) in this scenario?
 

Soniclife

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The mains "hum" is a measurement thing. I did not hear it at all. So I would not worry about it one way or the other.
Mine arrived yesterday, with my most sensitive IEMs I can hear hum when not playing music, it goes away when I touch any metal part of the case. Oddly it does not stop when you turn the volume knob to the standby position, and even odder it does not stop when you turn the power off with the physical switch on the back. Removing the power cord stops it.
 

Bhargu

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I placed an order for rHead so that my friend can pick it up when he comes over next week. I was thanking @amirm specifically for his timing with this review. I was on the lookout for a good desktop headphone amp for some months now. I didn't want to take a chance with anything after seeing some big fails of hyped products here. I might have pulled the plug with iFi Micro BL if not for some confusion with the quality of its volume pot (a colleague had some issues with it) even though I wasn't planning to spend that much (around $700 here).
 

Bhargu

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@amirm , I apologize for repeating the question. I wasn't sure if you saw the question.

You mentioned 16 dB gain for rHead and the dashboard shows 5.8 Vrms out. What was the input level? Also, according to the power level graphs, the peak Vrms should be around 6V. With a 16 dB fixed gain, won't there be heavy clipping with a 2V standard DAC output? Does it have some kind of dynamic gain control?
 
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amirm

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@amirm , I apologize for repeating the question. I wasn't sure if you saw the question.
Unfortunately I did not save the Dashboard view for Arcam so can't answer that. I do remember getting it to show the gain and it was a bit more than 16 dB. On levels, I do play with them now to get the best results so it is possible I was testing with lower than 2 volt input.
 

Anaz

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The mains "hum" is a measurement thing. I did not hear it at all. So I would not worry about it one way or the other.

And oh, welcome to the forum.
Thank you! Yes, I didn't notice a difference.
 

Anaz

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Mine arrived yesterday, with my most sensitive IEMs I can hear hum when not playing music, it goes away when I touch any metal part of the case. Oddly it does not stop when you turn the volume knob to the standby position, and even odder it does not stop when you turn the power off with the physical switch on the back. Removing the power cord stops it.
I'm using an iFi iPower ps with the rHead as I stated... Using sensitive IEMs (iBasso IT01) there's a a very, very, very faint buzz when I have the volume on mute that goes away when I touch the volume knob or case - actually, I didn't notice the buzz until you mentioned it or maybe I always had my hand on the volume control. When I turn the volume (even when I let go LOL), there is no buzz and the background is quiet until 3:00 - there's a small pop consistently around 9:30 though.
 
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amirm

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I'm using an iFi iPower ps with the rHead as I stated... Using sensitive IEMs (iBasso IT01) there's a a very, very, very faint buzz when I have the volume on mute that goes away when I touch the volume knob or case - actually, I didn't notice the buzz until you mentioned it or maybe I always had my hand on the volume control. When I turn the volume (even when I let go LOL), there is no buzz and the background is quiet until 3:00 - there's a small pop consistently around 9:30 though.
The iFi supply leaks mains which then couples into your audio product. It is a symptom of such switching supplies.
 

Jimmy

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I don't have experience with the ifi ipower, but more often than not manufacturers include crappy power supplies with their products to increase profits.

Normally I don't like wall wart adapters and replace them with power bricks. A brand that usually offers quality products at reasonable prices is Mean Well, be it under their own brand or as oem for many third parties.

For less than 20€ a high power regulable switching power supply can be purchased that will likely be much better and offer cleaner output than the average wall wart adapters included with many audio products.
 

derp1n

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Looks like the rHead uses a LM4562 opamp and PGA2311 for volume control.
 

Soniclife

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Mine arrived yesterday, with my most sensitive IEMs I can hear hum when not playing music, it goes away when I touch any metal part of the case. Oddly it does not stop when you turn the volume knob to the standby position, and even odder it does not stop when you turn the power off with the physical switch on the back. Removing the power cord stops it.
I returned the Arcam, as well as the hum there was a scratchy noise on one channel. Both of these problems were only audible with my most sensitive IEMs (JH Audio 13 Pro custom) so I don't know if what I got was slightly faulty, or it's a very sensitive IEM thing, but they are silent when plugged into my laptop or phone at all times.
 
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