Review and Measurements of Aune X7s and Arcam rHead Headphone Amps

[mindbomb]

With the aune, and with the topping a30 and topping dx7s, I'm having trouble getting a feel for how good they are as amps. How important is it to have a high damping factor? Is the 10x rule of thumb fine? I remember in the hugo 2 review, when different headphones were tested, it appeared that the 10 ohms of the topping was hurting performance even with 300 ohm headphones. But then solderdude said in another thread that he thought it was a measurement quirk.

Idk how I feel about all these otherwise solid tpa6120 amps.

 

[xineis]

You have to make that decision. On paper it should do better than these products.

Speaking of which, any chance that the Massdrop Liquid Carbon X is on the line for measurements, @amirm?

 

[Grave]

With the aune, and with the topping a30 and topping dx7s, I'm having trouble getting a feel for how good they are as amps. How important is it to have a high damping factor? Is the 10x rule of thumb fine? I remember in the hugo 2 review, when different headphones were tested, it appeared that the 10 ohms of the topping was hurting performance even with 300 ohm headphones. But then solderdude said in another thread that he thought it was a measurement quirk.

Idk how I feel about all these otherwise solid tpa6120 amps.

A 10 ohm output impedance should be fine for 80 ohm headphones or higher. I certainly did not notice any frequency response change using my Topping A30 with my 150 and 300 ohm headphones compared to the JDS Labs DAC/amps I used previously.

 

[Chung Huy Gouy]

With the aune, and with the topping a30 and topping dx7s, I'm having trouble getting a feel for how good they are as amps. How important is it to have a high damping factor? Is the 10x rule of thumb fine? I remember in the hugo 2 review, when different headphones were tested, it appeared that the 10 ohms of the topping was hurting performance even with 300 ohm headphones. But then solderdude said in another thread that he thought it was a measurement quirk.

Idk how I feel about all these otherwise solid tpa6120 amps.

It depends on the headphones you're using them for and their impedance curve. If the impedance of the headphones is low and the impedance curve is not linear, a high output impedance would colour the frequency response to a degree. This isn't always bad as it may flavour the frequency response to your liking. In addition, I'm thinking that some manufacturers may produce headphones with the mindset to pair them with amps of a higher output impedance.

 

[amirm]

Speaking of which, any chance that the Massdrop Liquid Carbon X is on the line for measurements, @amirm?

It is a very popular device and I love to test it. But no one has offered one.

 

[amirm]

It depends on the headphones you're using them for and their impedance curve. If the impedance of the headphones is low and the impedance curve is not linear, a high output impedance would colour the frequency response to a degree. This isn't always bad as it may flavour the frequency response to your liking. In addition, I'm thinking that some manufacturers may produce headphones with the mindset to pair them with amps of a higher output impedance.

Well explained. I am told Sennheiser did that with their headphone amp....

 

[Kyle / MrHeeHo]

It depends on the headphones you're using them for and their impedance curve. If the impedance of the headphones is low and the impedance curve is not linear, a high output impedance would colour the frequency response to a degree. This isn't always bad as it may flavour the frequency response to your liking. In addition, I'm thinking that some manufacturers may produce headphones with the mindset to pair them with amps of a higher output impedance.

I suspect that's what many audiophiles are really hearing when they think they're hearing "tube sound". Tube smplifiers tend to be designed with incredibly high impedances.

Back on topic: Decent performances from both it looks like, the output impedance of the Aune is a deal breaker for me though as I ave some headphones that are quite sensitive

 

[Krunok]

The Arcam rHead accepts XLR and RCA inputs, but only has 3.5mm and 6.3mm TRS headphone jacks. No 4-pin XLR output.

It was a joke, because @amirm wrote "It has both unbalanced and unbalanced inputs, but only unbalanced output."

 

[amirm]

It was a joke, because @amirm wrote "It has both unbalanced and unbalanced inputs, but only unbalanced output."

That it was.

 

[Chung Huy Gouy]

I am looking for an amp with low-impedance output and good clarity. Portable or desktop is not too important.

Factoring in the price difference, among Arcam rHead, iFi Audio Micro iDSD Black Label, or Topping NX4 DSD, which one is the best choice?

Or is it worthwhile to wait for the Massdrop THX AAA 789 and the measurement of it?

The specs on the THX AAA 789 looks insane for the price. Especially the THD+N, though debatable whether it is audible to human ears. Would be awesome to see it measured with the AP analyser.

 

[Krunok]

The specs on the THX AAA 789 looks insane for the price. Especially the THD+N, though debatable whether it is audible to human ears. Would be awesome to see it measured with the AP analyser.

https://audiosciencereview.com/foru...surements-of-the-massdrop-x-thx-aaa-789.3384/

 

[Suren]

If I am not going to listen at deafening levels would I notice any distortion with X7S through my m50x's since it's a 32 ohm headphone. Also what about 6xx a 300 ohm pair should I be worried ?

 

[DataX]

Thank you for this review @amirm, had been looking forward to the X7s measurements for a while.

A bit disappointed with the output impedance, though I wonder if this is why people typically refer to the X7s as a 'warm' sounding amp. I understand the higher output impedance will color/change the sound, however I don't understand the technical detail of how or why. If anyone has a good link to read up on this, I'd appreciate it.

If it's changing the frequency response, what would this graph tend to look like and would it be specific to each and every amp or amp+headphone/driver combo? Is this something that can be measured like what we see in some of the the DAC reviews?

I've always heard that different amps have a different sound signatures (tube amps in particular), but I don't understand why one would want that instead of a perfectly clean, flat output and just tweak the sound with an EQ/DSP instead.

 

[Sythrix]

If I am not going to listen at deafening levels would I notice any distortion with X7S through my m50x's since it's a 32 ohm headphone. Also what about 6xx a 300 ohm pair should I be worried ?

I would be more worried about the impedance mismatch between the m50x and the X7s. As far as actual distortion, you should be fine unless you routinely go over 115 dBSPL (pretty damn loud) on either of them, based on the power requirements of the headphones and Amir's measurements. Just do what you're planning volume-wise and you'll be fine. Amir's listening tests pointed to nothing noteworthy in terms of audible concerns.

 

[amirm]

A bit disappointed with the output impedance, though I wonder if this is why people typically refer to the X7s as a 'warm' sounding amp. I understand the higher output impedance will color/change the sound, however I don't understand the technical detail of how or why. If anyone has a good link to read up on this, I'd appreciate it.

Those kinds of subjective, uncontrolled listening tests unfortunately produce wrong conclusions. Levels need to be matched and AB switching done quickly to see if there is a difference. That is what I did and I can tell you with confidence there is no "warmth" there.

Now, it is possible to find a combination of headphone and this amp where the high output impedance varies the frequency response enough to make it tonally have more bass or something. But that needs to be planned and not a statement about the function of the amp.

 

[dc655321]

I understand the higher output impedance will color/change the sound, however I don't understand the technical detail of how or why. If anyone has a good link to read up on this, I'd appreciate it.

This may help your understanding.
HTH.

 

[Jimster480]

It is a very popular device and I love to test it. But no one has offered one.

I have a friend who has one, I will ask him about sending it to you.
Maybe I can offer him one of my A30's in the meantime

 

[Jimster480]

The specs on the THX AAA 789 looks insane for the price. Especially the THD+N, though debatable whether it is audible to human ears. Would be awesome to see it measured with the AP analyser.

2 people have offered this to Amir already.
I am one of them, it depends on who decides to mail it to him.
So far the other guy has decided to have it mailed directly to Amir from massdrop, if he does follow through then Amir will measure his.
Otherwise I will mail it to Amir after receiving it.

 

[Sythrix]

2 people have offered this to Amir already.
I am one of them, it depends on who decides to mail it to him.
So far the other guy has decided to have it mailed directly to Amir from massdrop, if he does follow through then Amir will measure his.
Otherwise I will mail it to Amir after receiving it.

I'm the other guy, I think. I am in the process of seeing if Massdrop will change the address, since you have to submit a request. Otherwise it will ship direct to me, and from there I was going to send it on. I was unaware that there was anyone else who had offered. I intend to follow through unless Amir says otherwise, but it makes no difference to me how he receives one, just so long as we get the measurements.

I believe he also said that he personally plans to get the THX 788 from Monoprice, so hopefully we'll have that one too, as I am interested in it as well.

 

[Suren]

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.