Review and Measurements of New JDS Labs Atom Headphone Amp

[flipflop]

Bass has its own place now rather than just giving an impression of it. Better instrument spacing and tone separation. No distortion even on tracks that have layers upon layers of sounds. Off the top of my head one by archive-bullets, towards the end it used to get distorted and non intelligible (everything muddled together) that it's actually funny. Cant believe an amp makes that much of a difference and i dont even have a an external dac yet.

What surprised me is that the added clarity made me notice new things in songs ive listened hundreds of times, i did some a\b testing and going back i can hear more or less the same stuff but it's like good 30-50% worse on onboard to be fair. Mobo dac must be still outputting a weak signal to the amp but even that gets amped really cleanly i didnt expect that big of an increase in audio quality and i went in expecting pretty much nothing.

There are cons though. Now since higher tones arent just cut off and things stand out by themselves on a track, it fatigues me way more... But now a good week+ later it doesn't bother me nearly as much. Expect a dac that feeds 2v clean data to amp to improve audio by another 10-20%. Onboard sound is good for what it is but it's nowhere near as lively.

I'm sure numerous other forums would appreciate your non-volume matched, non-blind impressions more than we do here.

MInd you the weak link is still onboard dac.

The weak link will always be your headphones until they have been properly equalized.

 

[Get a hearing test]

The dac is the weak link. If i game on a system gpu at near 100% usage i can hear power noise. Volume match lol. Im not comparing two amps/dacs its onboard vs atom. Maybe get a hearing test first buddy and then get the wax cleaned out. Really opens up the highs

 

[sjx007]

Thank you Amir for all your awesome work. I was silently reading through several threads and ended up buying Atom + SMSL SU-8 DAC. My headphones have really come alive.

 

[amirm]

Thanks for the kind words and you are welcome!

 

[Shadrach]

I finally received my JDS Atom. I've been using it for about a week now; approximately 40 hours of listening.
I bought it because I wanted something more portable than my valve based WAD83, and I was interested to hear what a measurably transparent amplifier would sound like. None of the rest of my equipment is measurably transparent.
For some unknown reason I believed my Sennheiser HD 595 headphones to be 600 ohm, I'll put this down to one of those senior moments
I measured them. They are in fact 50 ohm. The Atom drove them with ease with plenty to spare. It also drove my Beyerdynamic DT 880s without resorting to high gain at acceptable levels.
It seems the WAD83 is more distortion prone than I had thought.
I don't like the Atom's plastic case! I would happily pay another third of the price for a better looking case.
It's too light. In the end I used bluetack to try and stop the Atom trying to follow me around. This may sound like a very small complaint but there were a couple of occasions when the Atom moved enough to put considerable strain on my very short interconnects.
A locking headphone output socket would be a nice addition.
A good buy imo.

 

[confucius_zero]

Channel imbalance detected in a sample of two due to pot implementation?

 

[maxxevv]

That's strange indeed.

Mine doesn't exhibit that and I have listened to it on the HD800 too. I have mine board out of the case too at this point as I'm taking some dimensional measurements. Perhaps I should place my multimeter onto the volume pot too.

BTW, there was no need to rip out the rear panel to access the board. The case has just enough give to pry the board out of it.

 

[confucius_zero]

That's strange indeed.

Mine doesn't exhibit that and I have listened to it on the HD800 too.

Just a bad batch perhaps. Video author did mention a follow up after jds measures his defective products.

 

[amirm]

Very strange. Wish he had shown us some measurements of the output level so that we could compare with ours. If someone knows him, they should ask him to send it to me for measurement.

Wonder if his headphones are also slightly out of balance and the combination then becomes audible.

 

[PorchSong]

Very strange. Wish he had shown us some measurements of the output level so that we could compare with ours. If someone knows him, they should ask him to send it to me for measurement.

Wonder if his headphones are also slightly out of balance and the combination then becomes audible.

I would agree. I can "only hear" the imbalance on my HE-4xxi's and the HD 6xs when going from zero sound to "just hearing" sound. The right channel comes on before the left. But the second the left channel is heard, the atom has balanced sound on both sides. The pot starts around 7 o'clock and you can hear the right channel first, but by 8 o'clock they even out and I cannot hear any imbalance.

 

[mindbomb]

Considering that this is a dc coupled amp, are there certain dacs that should be avoided? Do dacs like the topping d30, topping d10, sdac, ol dac and modi 3 have negligible dc output? Does one of them stand out as particularly low?

 

[Irrelephant]

Very strange. Wish he had shown us some measurements of the output level so that we could compare with ours. If someone knows him, they should ask him to send it to me for measurement.

Wonder if his headphones are also slightly out of balance and the combination then becomes audible.

I was told that somehow my video made it to this thread so I've put together an account here.

This problem persisted on the three headphones I tested the Atom with. Although a limited collection of tests on an HD800, HD558, and Bose AE2, it was still an issue. Any other amplifier that I have had in the past has not exibited this issue, plus as I demonstrate in the video, removing the volume pot solves the problem.

I really liked what the Atom is able to do, and I still strongly recommend it, it just seems that I was extremely unlucky in my particular batch.

I greatly appreciate the offer to measure them, however I've sent them back to John at JDS as he seems very interested to measure them as well, and will hopefully get back to me shortly.

 

[amirm]

Thanks and welcome aboard. Any chance you could let us know what content you used that was very revealing of this issue? I know you said it was a mono track but would be good to have the exact one to try.

 

[Anubhav]

Hi @amirm .
Mate Thanks for all the info you provide us.
Today I recieved my JDS Labs Atom and ran it through & through ..It easily beat Schiit stack for me (Magni 2).

But somehow I feel it was underpowered to run my ATH R70x.
And more astonishingly when I ran back to back listening test, it seems to be inferior to Geshelli Labs Archel Pro Amp.
Archel easily powered my ATH-R70X, where as Atom had to be taken to 4pm (full volume).
Now I am not saying that I need full volume, but it still needed to be at 1pm with high gain as I was testing.
Volume is still not an issue --- CLARITY is.

I know you haven't done a comparison against Archel Pro or tested Archel Pro, just the DAC(Enog2).
Not sure if you can test it against the Geshelli Archel Pro, but I strongly believe there should be something interesting in there.

Thanks for all your efforts Mate

 

[Irrelephant]

Thanks and welcome aboard. Any chance you could let us know what content you used that was very revealing of this issue? I know you said it was a mono track but would be good to have the exact one to try.

I noticed it when in a Discord call at first, at which point I decided to try listening to some of my voice overs for videos, which are in mono. Afterwards I just started DSP correcting everything in my foobar2K to mono. I can post a sample of one of my voice overs if you'd like

 

[Toni71]

I received my Atom amp two weeks ago. I measured the cups with a db meter and pink noise yesterday.
There is no channel imbalance on my unit.
This is maybe not as good then measuring with a voltmeter, but i cant hear a channel imbalance either.
For what its worth.

(Just a guy from The Netherlands, not an JDS employee )

 

[Irrelephant]

I'm not entirely sure how to read these graphs however, the second unit seems to be significantly better than the first unit I received, and also seems to be much closer to perfect, particularly around halfway. I don't have a clear representation of where each physical position would be on the potentiometer, but the second unit does seem reasonable. This leads me to wonder whether I am simply used to a larger potentiometer being more balanced, or if there is another piece to the problem such as my headphones could be slightly right oriented 0.5dB, and with the combination of this error leads to it being more noticeable on a smaller pot, as @amirm suggests. This is strange to me though as I did test with multiple headphones and experienced the same imbalance.

Either way, it seems the tolerances are quite good, and for anyone worried about buying an Atom I wouldn't be.

 

[amirm]

The look the same as my measurements. The line shows deviation from 0 dB (ideal). Volume is at max and then reduced step by step. I don't know how the steps represent actual volume control position.

 

[onslash]

Grace SDAC, $80 at Massdrop. And also american made.

i believe sdac is american designed but made in china

 

[Phenylalanine]

I found a nice volume knob (aluminnuninuimum with set screw) on gdparts on ebay. I had to fashion a very short extension for the potentiometer though.

I just really like that it fits the style of the existing design while improving functionality as best as I could hope for.