Review and Measurements of New JDS Labs Atom Headphone Amp

[Gggggas]

Basically, group buys? What is it that you need help with?

I'd like some help from a fellow ASR member regarding the purchase of the Atom.
Since I know that it will cost me 200+usd and almost 2 months to be delivered I would like to have it shipped to Greece from someone in the States willing to help.
I'll surely give something extra for the help

 

[bboris77]

Two quick questions:

1. What is the input impedance of this amp?

2. What is the degree of bleed-through from one input to another, if any? It would be interesting to know whether the 3.5mm input measures as well as the RCA input.

Thank you.

 

[snip3r77]

anyone with the sdac-o2 and atom pls help to compare ? Am I missing much or just numbers assuming I’m using it with a hd6xx

 

[Grantman]

About a month ago I bought the FX-Audio Dac-X6 on the strength of ZReviews on youtube. This was to drive my newly purchased Seinheiser HD6XX (HD650) headphones. The HD6XX headphones really veered me onto a slippery slope of looking into the world of audio gear. Previously I wasn't interested in audio much at all, and it wasn't until my $8 sony earphones broke that this whole avalanche of audio research began. I'd always been mildly dissatisfied with my audio so this was now the time to sort it.

Anyway, I found the Dac-X6 definitely boosted the low end of the HD6XX vs my laptop onboard (Realtek ALC668 chip), but the onboard had better mids and highs. Aagh! The Dac-X6 was also muddier in general, lacking crispness/clarity. Looking at audioscience review of the Dac-X6 I could see why I felt the treble wasn't so great!

Anyway, somewhat disgruntled, and wondering if this audio quality thing was all in my head, I figured I'd throw more money at this. I wanted best bang for buck audioscience-measurement-wise. So I ended up buying the Grace SDAC and this new-on-the-market JDS atom amp to see if better audio was really out there.

I just received the SDAC today and paired with the JDS Atom through 3.5mm (I have some shorty ebay Ghent audio RCA cables still coming) I am glad to report that spending an additional $153.94 USD does get you significantly better audio.
(SDAC $82.81 + JDS Atom $136.12, ouch shipping! less FX-Audio X6 $64.99)

Build wise the Atom Amp is a very distant second to the Dac X6. The volume knob on the Atom is cheap and nasty with a plastic casting blemish and wobble, however the resistance of turning is all good. In the end I really don't care about the build so long as it doesn't break. I'm the type that'd probably settle for a cardboard case if the savings went to better audio quality.

The power brick that came with the Atom is clearly very high quality. It weighs a heck of a lot for the size. I'd gauge it weighs more than thirty X6 power bricks which feel completely empty.

Obviously given I've replaced the dac+amp I can't say the Atom gets the all credit for the audio improvement. I can say the SDAC+Atom sounds great to me, better than the Dac X6. The crispness is back with good treble and clear all round audio. Finally!

My feeling on the X6 is that it emphasized the low end more than SDAC+Atom, but it was in a slightly muddy way. Treble was really just 'not good'. The dac on the X6 might be fine, I can't say as I haven't tested separately.

 

[bravomail]

About a month ago I bought the FX-Audio Dac-X6 on the strength of ZReviews on youtube. This was to drive my newly purchased Seinheiser HD6XX (HD650) headphones.

Nice report!

 

[linesplice]

I have the liquid spark and the atom and it seems the liquid spark plays louder. That's not supported by what the measurements indicate, so I'm scratching my head wondering why? I should note, this is true for both on low or high gain - and I recognize they don't have the same gain.

 

[Tatteredmidnight]

anyone with the sdac-o2 and atom pls help to compare ? Am I missing much or just numbers assuming I’m using it with a hd6xx

I returned my Massdrop sdac+o2 unit due to multiple QC issues (incorrect gain and USB issues, you can read my review there if you're really interested). I replaced it with an Atom and recommissioned my SMSL M8 DAC.

While I didn't have them simultaneously, my impression is that they are both audibly transparent. The only meaningful difference, sound wise, is the greater available power from the Atom. The other side of that coin being the inconvenience of separate devices compared to an integrated solution.

If the sdac+o2 is supplying sufficient power, and functioning properly, I'd be hard pressed to think of a reason to replace it.

 

[GGroch]

I have the liquid spark and the atom and it seems the liquid spark plays louder.....I should note, this is true for both on low or high gain - and I recognize they don't have the same gain.

Hi linesplice,
How did you conclude that the Liquid Spark plays louder? What were the circumstances? With info about the headphones and source and what you noticed we can probably be more help.

But I will provide a very long guess of what you experienced anyway

As you said, the gain settings (both High & Low) on the Spark are set higher than the High & Low settings on the Atom.
What this means is that if both Amps are given the same input voltage from the source (lets say 2 volts which is a standard..the OL DAC puts out 2 Volts)..... Then if you set the volume knob on both to the same spot (say 10:00 o'clock) the Liquid Spark will be louder.

However, if you crank up both amps until they start to distort, the volume levels should be very close. The Liquid spark will distort at a lower volume knob setting (say 2 O'clock for example)...and the Atom will start to distort at a higher volume setting (say 4:00 O'clock)...but the actual loudness will be close to the same. Note that Amir judges the maximum power to be where distortion starts to rise rapidly. Amps can play still louder....they just will not sound so good.
NOTE: There are circumstances where the Spark will play louder. Lets say your Source cannot put out the standard 2 Volts...but instead only puts out 1/2 volt. You theoretically could fully crank both volume controls to maximum and the Spark would be louder because it has more gain..and neither amp would be distorting at max cranked volume.

That is one reason some companies use higher gain settings. Another reason is that it makes some people (Like Zeos Pantera apparently) think amps that use higher gain have more power because they are louder at any given knob setting.

Others like JDS on the Atom use lower gain so that you can use more of the volume knob to get more precise setting. On some amps I have used I can only use the 1st 1/4 of the volume control with some headphones because their gain is set so high.

 

[DaaDaa]

please review the Loxjie P20. im dying to know how it drives low impledence planars.

 

[Roen]

About a month ago I bought the FX-Audio Dac-X6 on the strength of ZReviews on youtube. This was to drive my newly purchased Seinheiser HD6XX (HD650) headphones. The HD6XX headphones really veered me onto a slippery slope of looking into the world of audio gear. Previously I wasn't interested in audio much at all, and it wasn't until my $8 sony earphones broke that this whole avalanche of audio research began. I'd always been mildly dissatisfied with my audio so this was now the time to sort it.

Anyway, I found the Dac-X6 definitely boosted the low end of the HD6XX vs my laptop onboard (Realtek ALC668 chip), but the onboard had better mids and highs. Aagh! The Dac-X6 was also muddier in general, lacking crispness/clarity. Looking at audioscience review of the Dac-X6 I could see why I felt the treble wasn't so great!

Anyway, somewhat disgruntled, and wondering if this audio quality thing was all in my head, I figured I'd throw more money at this. I wanted best bang for buck audioscience-measurement-wise. So I ended up buying the Grace SDAC and this new-on-the-market JDS atom amp to see if better audio was really out there.

I just received the SDAC today and paired with the JDS Atom through 3.5mm (I have some shorty ebay Ghent audio RCA cables still coming) I am glad to report that spending an additional $153.94 USD does get you significantly better audio.
(SDAC $82.81 + JDS Atom $136.12, ouch shipping! less FX-Audio X6 $64.99)

Build wise the Atom Amp is a very distant second to the Dac X6. The volume knob on the Atom is cheap and nasty with a plastic casting blemish and wobble, however the resistance of turning is all good. In the end I really don't care about the build so long as it doesn't break. I'm the type that'd probably settle for a cardboard case if the savings went to better audio quality.

The power brick that came with the Atom is clearly very high quality. It weighs a heck of a lot for the size. I'd gauge it weighs more than thirty X6 power bricks which feel completely empty.

Obviously given I've replaced the dac+amp I can't say the Atom gets the all credit for the audio improvement. I can say the SDAC+Atom sounds great to me, better than the Dac X6. The crispness is back with good treble and clear all round audio. Finally!

My feeling on the X6 is that it emphasized the low end more than SDAC+Atom, but it was in a slightly muddy way. Treble was really just 'not good'. The dac on the X6 might be fine, I can't say as I haven't tested separately.



View attachment 18620

The best part is, you don't have many significant gains, if any, left to chase.

 

[linesplice]

GGroch,

Good points. I don't have any fancy gear, but I did dig out my old Fluke 179DMM and I was only getting about 1.247mv from the DAC output. You made a point this could be a contributing factor. I don't know. Interesting though.

Thanks again.

 

[snip3r77]

I returned my Massdrop sdac+o2 unit due to multiple QC issues (incorrect gain and USB issues, you can read my review there if you're really interested). I replaced it with an Atom and recommissioned my SMSL M8 DAC.

While I didn't have them simultaneously, my impression is that they are both audibly transparent. The only meaningful difference, sound wise, is the greater available power from the Atom. The other side of that coin being the inconvenience of separate devices compared to an integrated solution.

If the sdac+o2 is supplying sufficient power, and functioning properly, I'd be hard pressed to think of a reason to replace it.

Thanks for the reply. How do you ascertain that the gain is wrong? Was it a batch that was manufactured months ago?

 

[TungstenC]

Thanks for the reply. How do you ascertain that the gain is wrong? Was it a batch that was manufactured months ago?

It's the first batch(09/17) that had the wrong gain, Massdrop sent out emails to notify first batch buyers about this issue (myself included).

 

[snip3r77]

It's the first batch(09/17) that had the wrong gain, Massdrop sent out emails to notify first batch buyers about this issue (myself included).
View attachment 19158

Thanks for the info. I got it recently so I think I'd be fine.

 

[Tatteredmidnight]

Thanks for the info. I got it recently so I think I'd be fine.

I suspect you'll be more than fine, just not as fine as with an Atom (couldn't resist). The only reason I returned that unit, and ultimately came here, were the QC issues. Well, I was also accused of being an ASR zealot on the Massdrop comments before I'd see this forum, so that's also partly responsible for making me awards of it.

This forum has saved me hundreds of dollars (maybe more), and lead me to the Atom, a device that perfectly fit my needs. Thank you so much for making this resource available @amirm.

 

[huspas]

Does Atom capable of driving very inefficient planars like HE-560 on low gain? Amirm's measurements shows that Atom is superior on low gain. I probably couldn't hear the difference between two by the way.

 

[GGroch]

Is the Atom capable of driving very inefficient planars like HE-560 on low gain? Amirm's measurements shows that Atom is superior on low gain.....

The HE-560s are my go-to headphones. So, the answer:

1. Yes, Quite Capable - When I feed it the full output of my DAC and max the Atom volume at low gain it is very loud, louder than I ever listen. BUT

2. I am not sure the Atom is superior on low gain. The Signal To Noise Measurement shown is better at high gain (but both are far better than you can hear).

Amir said, " At lower output levels of say 1 volt (not shown), the distortion goes so far down that the mains spike at 60 Hz dominates. Since our hearing sensitivity there is some 50 dB higher, this device becomes essentially distortionless....This is in low gain by the way. High gain was not quite as good."

If I understand this correctly...if you are listening to headphones very softly, then Low Gain is a bit better. Of course, if you are listening very softly, then of course High Gain is not needed. Do not be paranoid about listening loud on high gain...(except in terms of how loud volumes might damage your hearing.)

If I am misunderstanding what was said..please correct me on this.

 

[ascorbyl]

The HE-560s are my go-to headphones. So, the answer:

1. Yes, Quite Capable - When I feed it the full output of my DAC and max the Atom volume at low gain it is very loud, louder than I ever listen. BUT

2. I am not sure the Atom is superior on low gain. The Signal To Noise Measurement shown is better at high gain (but both are far better than you can hear).

Amir said, " At lower output levels of say 1 volt (not shown), the distortion goes so far down that the mains spike at 60 Hz dominates. Since our hearing sensitivity there is some 50 dB higher, this device becomes essentially distortionless....This is in low gain by the way. High gain was not quite as good."

If I understand this correctly...if you are listening to headphones very softly, then Low Gain is a bit better. Of course, if you are listening very softly, then of course High Gain is not needed. Do not be paranoid about listening loud on high gain...(except in terms of how loud volumes might damage your hearing.)

If I am misunderstanding what was said..please correct me on this.

Yes, if low gain is enough to power your headphones, use it since it is usually better (as long as it is not <1.0x gain, such as on "Gain I" in the THX AAA 789). Check out this study done by Amir: thread link.

He compares the Magni 3 and the JDS Labs Atom on low and high gains.

 

[Dirk Wright]

My Atom is here. My initial impression it is a tad cleaner sounding than the O2 which I always thought was a tiny bit bright or maybe even glassy on the top end, nothing like that here, I'll have to spend some time with both to see if this is something I can reliably detect. It came with a massive 16W transformer, for some reason it measured 18VAC not 16 as labeled, probably it is rated at 16V under load, I don't think it is a reason to be concerned in any case. Low gain setting is sufficient to drive HD6XXs to painful levels at 3-4 o'clock. Pretty impressed with clarity, look and feel is basic yet satisfying, so far it looks like a keeper.

If the Atom is using a capacitor multiplier, then they need more current from the transformer than otherwise, hence the bigger size.

 

[Dirk Wright]

This is a much better design in my opinion than the O2. I've been using a similar design for many years now in my headphone amps. The LME49600 buffer has good potential if the power supply is up to it. If a precision opamp with low Vos is used as the gain stage then no servo is really needed. I used the LME4910 until it was discontinued. I did another trick to lower the noise even further, but I won't share that here.