Review and Measurements of New JDS Labs Atom Headphone Amp

[nyxnyxnyx]

And i also was quite a bit surprised to see Atom standing up to Mjolnir 2 quite easily in term of cleanliness and power ( SE ) . I attended a local audio offline event quite a few weeks ago and everyone was surprised at how clean this amp is , and the event concluded with 2 new orders for Atom .

By the way i have had this question for awhile now : If not for sheer curiosity , or simply looking for something new/different , is there even a point in buying other amplifiers? And if you would upgrade your amplifier from Atom , what would it be?

 

[Chiv]

And i also was quite a bit surprised to see Atom standing up to Mjolnir 2 quite easily in term of cleanliness and power ( SE ) . I attended a local audio offline event quite a few weeks ago and everyone was surprised at how clean this amp is , and the event concluded with 2 new orders for Atom .

By the way i have had this question for awhile now : If not for sheer curiosity , or simply looking for something new/different , is there even a point in buying other amplifiers? And if you would upgrade your amplifier from Atom , what would it be?

Only reason I would upgrade from my atom would be if I needed balanced outputs, in which I would get the THX AAA 789. Otherwise I'm at my personal endgame with the ASR combo (KTB + atom)

 

[maxxevv]

You could also look for 15VAC 30VA or something. (Toroids have less stray magnetic fields but higher leakage currents)
something like this (windings in parallel... make sure they are connected in parallel correctly)
or this (with windings in series) which is 18V 15VA

The best transformers are R-cores but are a bit more expensive. These have very low mains leakage.
This particular one will provide you with 15V (use 2 windings in parallel) or 18V (2 other windings in series)

When loaded with the Atom there will probably be around 16VAC on it.
The object of the game is to have enough DC voltage to drop over the regulators.
The regulators output voltage is 15VDC so you need 18VDC minimum on the regulator input and assuming ripple will be 1V or so, 19V DC or higher is perfect.

15V AC will give you about 20 VDC but in reality will probably be around 22 VDC in idle.
16V AC will give you about 21.5 VDC but in reality will probably be around 23 VDC in idle.
18V AC will give you about 24 VDC but in reality will probably be around 27 VDC in idle.

All of these options will work.
The higher the unregulated DC voltage is the warmer/hotter the regulators will become.
There won't be a difference in performance nor sound.

Hi Hans, @solderdude ,

managed to get an R-Core with a 16V 1A output with and additional 10V 1A line.
Amazingly, those guys in China seems to have produced my transformer specifically o order. The date stamp was actually the day after my order for it !

Going to use the additional line as a USB 5V output socket. So I can power other USB powered devices with it.

 

[Grattle]

Off topic a little , i'm getting another amp called Krell KSA5 (Clone) , does anyone here know it? Or have experienced with it in the past?

I was perfectly content with Atom and had no logical reasons to sell it , but due to this sheer curiosity i had , i ended up selling Atom and i am regretting a little , may have to re-buy it if my new amp sucks .

What do your ears tell you?

 

[nyxnyxnyx]

What do your ears tell you?

My ears told me that they were happy with the sound quality Atom brought , but i have this bad habit of wanting to experience new things that i am trying to shake off , i sold it . I guess i was audiophooled by my own impulsive curiosity haha

 

[magicscreen]

My ears told me that they were happy with the sound quality Atom brought , but i have this bad habit of wanting to experience new things that i am trying to shake off , i sold it . I guess i was audiophooled by my own impulsive curiosity haha

Who knows, you might like more the sound of the Krell KSA5 (Clone). There is some music that sounds better with the Loxjie P20 than the Atom.
By the way, there will be no Loxjie P20's review by Amir?

 

[solderdude]

He reviewed the D20 (which did not do well)
The P20 also doesn't measure that well.

You meant: There is some music where I preferred the coloration of the Loxjie P20 to the neutral sound of the Atom

 

[Veri]

I briefly tried the P20 but had to return it to amazon. The output impedance is quite high (SBAF is currently down but it was like 50ohm) and will mess with most headphones. If there's one thing I detest it's boominess

 

[Silou]

Did someone try the preouts of the Atom in combination with powered speakers? I would like to replace my bookshelf speakers with something active, but I am a bit afraid of ground loops I use the Tone Board as DAC.

 

[Swtoby]

Did someone try the preouts of the Atom in combination with powered speakers? I would like to replace my bookshelf speakers with something active, but I am a bit afraid of ground loops I use the Tone Board as DAC.

Not with powered speakers, but I use the Atom as my main preamp into a Crown XLS 1502 driving Vandersteen 2s and I have no ground loop.

 

[ripvw]

Did someone try the preouts of the Atom in combination with powered speakers? I would like to replace my bookshelf speakers with something active, but I am a bit afraid of ground loops I use the Tone Board as DAC.

same setup as you - Tone Board into the Atom, then Atom to JBL 308P MKII via Benchmark XLR/RCA cables:

https://www.audiosciencereview.com/...-monitors-first-impressions.7977/#post-194019

no ground loops:

https://www.audiosciencereview.com/...power-cord-blind-test.8086/page-5#post-201873

 

[Silou]

same setup as you - Tone Board into the Atom, then Atom to JBL 308P MKII via Benchmark XLR/RCA cables:

https://www.audiosciencereview.com/...-monitors-first-impressions.7977/#post-194019

no ground loops:

https://www.audiosciencereview.com/...power-cord-blind-test.8086/page-5#post-201873

Nice! I was looking at the 308s aswell but they might be to big for my room.

 

[noobizfury]

Hi long time lurker here, registered to say Thank you Amir for reviewing this product.

 

[maxxevv]

Nice! I was looking at the 308s aswell but they might be to big for my room.

Take a look at the 306P's instead then.

They are a lot closer to the 308p's in spec's than they are to the 305p's. But size wise, they are closer to the 305p's.
Very good option IMO if one desires more power and a lower frequency response than the 305p but can't live with the bulk of the 308p's.

 

[Silou]

Take a look at the 306P's instead then.

They are a lot closer to the 308p's in spec's than they are to the 305p's. But size wise, they are closer to the 305p's.
Very good option IMO if one desires more power and a lower frequency response than the 305p but can't live with the bulk of the 308p's.

I saw them but they are actually more expensive than the 308p. The lower frequencies are the main problem in my room at the moment. Maybe I should just get a UMIK1 and tweak the speakers.

 

[Music1969]

Finally, here is the channel imbalance versus volume position:

Worst case error occurs as usual close to the end of the range.

Hi @amirm

Can you kindly explain your x-axis (time) here.

It's starting from max volume position at t=0, down to min volume position?

 

[iazriel]

Your lights please to a noob. I recently got my Atom along with DT 770 pro 250ohm. If I don't use gain, the volume I get is exactly the same as my onboard sound card and I have to crank it to 2-5 o'clock to be somewhat fine. With gain, it sounds really fine and loud around 12 o'clock and by 3 o'clock is already too loud, but I wonder if gain has an impact to the sound quality. I hope not because without gain I get no difference volume wise compared to my onboard solution.

 

[Azeia]

Your lights please to a noob. I recently got my Atom along with DT 770 pro 250ohm. If I don't use gain, the volume I get is exactly the same as my onboard sound card and I have to crank it to 2-5 o'clock to be somewhat fine. With gain, it sounds really fine and loud around 12 o'clock and by 3 o'clock is already too loud, but I wonder if gain has an impact to the sound quality. I hope not because without gain I get no difference volume wise compared to my onboard solution.

I haven't checked all the pages so I dunno if there is a graph that compares low and high gain, but it's generally understood that for the Atom, you get no additional audible distortion at high gain. If you measured it however, it would probably be a bit higher on the graph for high than low gain, but again, this shouldn't be audible at all. The Atom is regarded to be one of the cleanest amps out there, in the same league as THX AAA 789.

The main purpose of the switch is that different headphones need different amounts of power to drive; on a sensitive headphone, the high gain would be way too strong and the volume knob would therefore be somewhat annoying to use as you'd only ever have it slightly turned up and it would already be too loud. So the gain switch lets you deal with that by giving you different settings for hard to drive vs easy to drive headphones.

I'm pretty sure the 250 Ohm DT 770s are difficult to drive; slightly easier than my 250 Ohm DT 990s which are the open-back version of the 770s, but still. These seem to be pretty difficult to power, my DX3 Pro just barely gets my 990s to a comfortable listening level at high gain, but with zero headroom for quiet tracks; I'm definitely going to need a better amp in future for them. =)

(FYI, the DX3 in high gain has about half the power as Atom in high gain, if you're curious for comparison purposes)

 

[iazriel]

Ah I see, really helpful. So, as long as there aren't any audible differences I will keep using it to get to comfortable volume levels. Thanks for your answer!

 

[Silou]

Ah I see, really helpful. So, as long as there aren't any audible differences I will keep using it to get to comfortable volume levels. Thanks for your answer!

Use low gain unless you really need more power. The Atom measures a lot better in low gain than it does in high gain. There is a little study on ASR about gains which compares the Magni 3 and the Atom in their different gains. To lazy to link it now but you will find it anyway