Review and Measurements of New JDS Labs Atom Headphone Amp

[Fluffy]

@maigonis
I have the Focusrite 2i2 2nd gen, and I also had some distortion issues with it at high volumes into some headphones. The 6i6 is not that different, and as far as I see they both have pretty limited voltage swing. The 6i6 specs note a +13 dbu, which translates to 3.5 VRMS, while the Atom has up to 8.6 VRMS according to it's specs. So driving high impedance headphones it should be at least twice as powerful. And I guess there are other problems with the 6i6 headphone amp that aren't noted in its specs.

In short, the atom seems to be able to drive pretty much everything. If something distorts with it, it's likelier to be the headphones themselves.

 

[FrantzM]

@maigonis
I have the Focusrite 2i2 2nd gen, and I also had some distortion issues with it at high volumes into some headphones. The 6i6 is not that different, and as far as I see they both have pretty limited voltage swing. The 6i6 specs note a +13 dbu, which translates to 3.5 VRMS, while the Atom has up to 8.6 VRMS according to it's specs. So driving high impedance headphones it should be at least twice as powerful. And I guess there are other problems with the 6i6 headphone amp that aren't noted in its specs.

In short, the atom seems to be able to drive pretty much everything. If something distorts with it, it's likelier to be the headphones themselves.

+1

 

[AndrovichIV]

Tnx. I have concerns about buying them because I bought Atom for AKG K712 Pro and they still continued to distort. I'm buying new headphones for about almost a year now, AKG was the 7th pair that I have sent back - I'm a bit tired from this. Almost all headphones that I tried had issues whit distortion, Beyer DT 770, 2x 32 Ohm and 2x 80 Ohm versions, AKG K275 (M50x I just didn't liked, but no distortion). My DAC is Focusrite Scarlett 6i6 2nd gen and it is know for weak headphone amp, so I got Atom now. I don't want to send anything back again as I'm a bit embarrassed about this.

I'm sure that source is not distorting, I check whit commercial music on My current headphones and speakers, all are clean.

1) what OS are you using? Does the distortion still occur when you're in bit perfect mode? 3) which DAC (or on-board) are you using?, 4) does the distortion reduce if you turn the digital volume down?

I think it's far more likely that the distortion you're hearing comes from the OS which is resampling your music or similar

If you still need more power for whatever reason though, you might want to check the Project Polaris amp (which Armirm reviewed here). You will go deaf before the amp distorts too much

 

[maigonis]

That's strange. Lightning rarely strikes 7 times in the same spot. Have you considered the levels at which you're listening? Does the distortion you're hearing go away at lower levels?

I don't listen loud, if I feel pain in ears, or discomfort, I dial volume down. Usually level is moderate, maybe a bit higher. On lower volume distortion is reduced, but it is not going away. Maybe My ears or Me are broken? I currently own Superlux 662F cheapos and they sound fine. Of course sound quality is bad comparing to other headphones that cost more, but distortion free. Maybe music I listen to is mastered in that way and I till now haven't heard that in Superlux cans? No idea, this is a big mistery for Me.

 

[maigonis]

@maigonis
I have the Focusrite 2i2 2nd gen, and I also had some distortion issues with it at high volumes into some headphones. The 6i6 is not that different, and as far as I see they both have pretty limited voltage swing. The 6i6 specs note a +13 dbu, which translates to 3.5 VRMS, while the Atom has up to 8.6 VRMS according to it's specs. So driving high impedance headphones it should be at least twice as powerful. And I guess there are other problems with the 6i6 headphone amp that aren't noted in its specs.

In short, the atom seems to be able to drive pretty much everything. If something distorts with it, it's likelier to be the headphones themselves.

This feel helpful. Yes, Scarletts are weak and now I hear how Focusrite shapes and colors sound in headphone amp. Not all is bad, but bass is lowered and treble is pushed forward, even mids. It feels like that amp is tuned for vocalist or acoustic guitar player, not for mixing, mastering, sound design. On Atom whit RCA connection coming from 6i6 trs outputs sound becomes more as is, I can finally feel low end as it should and coloration is mostly gone.

Seems like I'll order DT 770 Pros, tnx all for help. Sorry if I post double as I'm replying on phone.

 

[NAYRA]

what's the SINAD of high gain? Thanks

The Atom is a nice auto clicker word unscrambler jumble solver departure from the JDS O2 in having proper RCA connectors in the back and 1/4 headphone jack in front (and 3.5mm in the back):

 

[Fluffy]

This feel helpful. Yes, Scarletts are weak and now I hear how Focusrite shapes and colors sound in headphone amp. Not all is bad, but bass is lowered and treble is pushed forward, even mids. It feels like that amp is tuned for vocalist or acoustic guitar player, not for mixing, mastering, sound design. On Atom whit RCA connection coming from 6i6 trs outputs sound becomes more as is, I can finally feel low end as it should and coloration is mostly gone.

Seems like I'll order DT 770 Pros, tnx all for help. Sorry if I post double as I'm replying on phone.

Uh, what? That sounds weird. First of all, if you listen on lower volumes you shouldn't run into the clipping point of the amp. I had issues with it clipping when pushing low sensitivity headphones to high volumes, but in normal headphones and volumes it was fine. I'm not sure what sort of distortion you are hearing, but it's probably not related to the voltage swing.

As for the coloration, that also shouldn't be present. Unless it's a really crappy amp, it shouldn't "lower bass" or "push treble forward". Focusrite is a pretty respectable company that gears towards professionals, so there is very little probability that they have a product that does that. Mine doesn't color anything, it's just weak, that's it.

If you hear distortion on all of these headphones at low volumes, I think there is some other factor at play.

 

[cryptout]

This was a fun read, happy Atom user here!

 

[amadeuswus]

In a blog post dated 10/24/19, John Seaber of JDS Labs discusses how the Atom amp has been improved, e.g., better potentiometers for tighter channel balance :

https://blog.jdslabs.com/2019/10/how-atom-amp-has-improved-in-2019/

 

[hyperknot]

I've finally received my custom Ghent Audio A01 cable in black color, so I could finally test if the Khadas Tone Board in Audiophonics case gets lifted or not, when placed on an JDS Atom.

Good news: not, they look perfect. Actually kind of cable porn with these shiny RCA connectors.

The bad news is that these connectors are quite loose, by that I mean 3 out of 4 is looser than a cheap "plastic" RCA cable I have at home. I've emailed Ghent about it and I'm waiting for his reply.

In conclusion, I'm really happy with this setup!

 

[nyxnyxnyx]

Welp there's something i want to ask but don't know where so imma just post it here due

Is there a way to reduce amplifier gain? I'm using some DIY amp while waiting for my atom but i believe it has too much gain .

 

[hyperknot]

Welp there's something i want to ask but don't know where so imma just post it here due

Is there a way to reduce amplifier gain? I'm using some DIY amp while waiting for my atom but i believe it has too much gain .

It has no gain in the normal mode, only 1x!

 

[solderdude]

Welp there's something i want to ask but don't know where so imma just post it here due

Is there a way to reduce amplifier gain? I'm using some DIY amp while waiting for my atom but i believe it has too much gain .

In some DIY amps one can reduce the gain. In others one cannot. It all depends on whether or not uniti-gain stable opmaps are used or when a discrete design has compensation made for a certain gain.
You would have to post the schematic to tell.

Perhaps just reduce the input level of said temporary DIY amp.
The Atom has selectable gain so should not be a problem.

 

[nyxnyxnyx]

It has no gain in the normal mode, only 1x!

I mean , it's only a theory but i think it has too much gain because i have tried several headphones with different ohm and efficiency but they all go loud at the same volume (9-10 o clock according to volume knob)

Should i lower volume on my pc? I kinda want to test the limit of this amp too

 

[nyxnyxnyx]

In some DIY amps one can reduce the gain. In others one cannot. It all depends on whether or not uniti-gain stable opmaps are used or when a discrete design has compensation made for a certain gain.
You would have to post the schematic to tell.

Perhaps just reduce the input level of said temporary DIY amp.
The Atom has selectable gain so should not be a problem.

This DIY is supposed to measure at 6w at 32ohm , with an output impedance of 8 , i believe it has bad SINAD ratio because i can hear distortion if i turn it louder . But i have tried several high power amplifier (even a 10w load at 32ohm) and they don't sound as "loud" as this one .

I want to know how bad/good the amp will sound past noon , is there a safe way for me to do it without damaging my headphones?

 

[solderdude]

What the hell are you driving with it ? HE6 ? K1000 ? Susvara ? Sendy ? or T50RP ?

 

[nyxnyxnyx]

What the hell are you driving with it ? HE6 ? K1000 ? Susvara ? Sendy ? or T50RP ?

Currently i am trying this amp out with some old AKG 240/701/501 , Beyer T1 , DT990250Ohm , HD650 , HE400 and that's it lol .

 

[solderdude]

So an output voltage of at least 14V in higher impedance headphones.

That should play the Beyer T1 , DT990-250Ohm , HD650 to very loud and undistorted levels.
The 990 doesn't like to be played very loud.

When the HD650 sounds distorted on this amp either the source or amp are suspect.

The K501 also does not like to be played loud and starts to distort at realistic levels.

 

[flipflop]

The K501 also does not like to be played loud and starts to distort at realistic levels.

How do you know this?

 

[solderdude]

How do you know this?

https://diyaudioheaven.wordpress.com/headphones/measurements/akg/k501/

It is a bit similar to the KSC75/PortaPro in behavior at higher levels (they don't sound the same).
Work great at 'normal' listening levels but fall apart at higher levels.
Experimented quite a lot with it.