• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Review and Measurements of New JDS Labs Atom Headphone Amp

JohnYang1997

Master Contributor
Technical Expert
Audio Company
Joined
Dec 28, 2018
Messages
7,175
Likes
18,292
Location
China
No, not at all, but I'll start reading the thread again...I'm sure i missed something. It's probably another NJM2068 that is actually the gain-adjust, sorry if this was already posted somewhere.
njm2068 is a dual opamp. And atom used two of those. So half of the 2068 used as input/gain stage and the other half is the composite amplifier with 49600.
It's essentially the el amp but cost down.
How do i know? I have el amp and i used multimeter to get the circuit.
So the signal path should be:
input - half2068 - volume pot - capacitor - half2068 - 49600
 

AresHarvest

Active Member
Joined
Sep 5, 2018
Messages
135
Likes
80
I just had the EXACT same thing happen to me. It only happened once and never again. I emailed their support to see what they think. Has it happened to you since?

It hasn't happened since then, I'll report back if it does.
 

ishmeister

Active Member
Joined
Jul 20, 2018
Messages
116
Likes
103
Location
England

Nabobalis

Member
Joined
Feb 11, 2019
Messages
7
Likes
0
You got lucky then :) - I ordered from JDS a week ago and it only just left Chicago in transit to the "next destination", whatever that is . Also, I'll have to pay another £20 in VAT when it arrives :(

Yeah I am still waiting on mine, it has had the status for nearly 3 weeks now. Hopefully it arrives soon.
 

bboris77

Senior Member
Joined
Oct 23, 2018
Messages
444
Likes
931
If anyone is interested at how cool the Atom runs - my room is at 22C and the warmest area of the case is running at 32C. It is the top left area where all the capacitors are. This is exceptionally cool for an amp, but if you are stacking something smaller on top of it (like the Topping D50), you may want to leave that corner uncovered. My D50 ran around 34C when stacked on top of the Atom and 29C when on its own. Still all well within safety margins for this type of equipment.
 

Kane1972

Active Member
Joined
Dec 11, 2018
Messages
298
Likes
103
Been touting the Atom on Gearslutz website (music gear/recording). One person says the 0.6dB imbalance between L&R is too high for critical mixing etc. However, this is worse case scenario right? How is the L&R imbalance compared to other headphone amps?
 

flipflop

Addicted to Fun and Learning
Joined
Feb 22, 2018
Messages
927
Likes
1,240
Been touting the Atom on Gearslutz website (music gear/recording). One person says the 0.6dB imbalance between L&R is too high for critical mixing etc. However, this is worse case scenario right? How is the L&R imbalance compared to other headphone amps?
JDS Labs Atom Headphone Amplifier Channel Imbalance Measurement.png
 

Kane1972

Active Member
Joined
Dec 11, 2018
Messages
298
Likes
103
yeah, I'd seen that, so according to that graph at many volume knob positions the imbalance will be next to nothing. Not sure how to read the graph with regards to knob position though to avoid the 0.5dB imbalance, but it appears that from 1/2 turned up till about 3/4 one would be getting negligible imbalance?
 

flipflop

Addicted to Fun and Learning
Joined
Feb 22, 2018
Messages
927
Likes
1,240
yeah, I'd seen that, so according to that graph at many volume knob positions the imbalance will be next to nothing. Not sure how to read the graph with regards to knob position though to avoid the 0.5dB imbalance, but it appears that from 1/2 turned up till about 3/4 one would be getting negligible imbalance?
Yes, the imbalance ranges from 0 to 0.3 dB in most volume positions. It's not something that will be noticeable during normal music listening and probably not something that could be detected by most people in a DBT either.
 

GoMrPickles

Active Member
Forum Donor
Joined
Nov 6, 2018
Messages
170
Likes
182
yeah, I'd seen that, so according to that graph at many volume knob positions the imbalance will be next to nothing. Not sure how to read the graph with regards to knob position though to avoid the 0.5dB imbalance, but it appears that from 1/2 turned up till about 3/4 one would be getting negligible imbalance?
On mine, at the lowest volume I can hear, just for testing purposes, volume knob just above "off", the Atom's left channel is silent and there's sound from the right channel. At any volume I'd actually listen to, I can't perceive any imbalance. I do not hear this with the THX 789 AAA: I perceive the sound as equal in both channels until I can't hear anything. Simple sighted tests with music, not generated tones.

0.6dB imbalance between L&R is too high for critical mixing
I would argue that a $100 headphone amp is not designed for critical mixing. Or, I would wonder why one is mixing at barely audible levels.
 

unicore

Member
Joined
Jan 20, 2019
Messages
17
Likes
5
Location
Croatia, Zagreb
You got lucky then :) - I ordered from JDS a week ago and it only just left Chicago in transit to the "next destination", whatever that is . Also, I'll have to pay another £20 in VAT when it arrives :(
Yeah, I was so close to order from USA and pay VAT and duty costs, but they got it on time. You can always message JDS Labs and ask them to check your package status for you. I got a feeling that they are a very nice people willing to help.
 
OP
amirm

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
44,368
Likes
234,385
Location
Seattle Area
yeah, I'd seen that, so according to that graph at many volume knob positions the imbalance will be next to nothing. Not sure how to read the graph with regards to knob position though to avoid the 0.5dB imbalance, but it appears that from 1/2 turned up till about 3/4 one would be getting negligible imbalance?
The red line shows the output level which is near 500 millivolts. Worst case situation is around just 20 millivolts. The unit essentially mutes around 5 millivolts so you are pretty close to minimum setting on the volume control when that happens.
 
OP
amirm

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
44,368
Likes
234,385
Location
Seattle Area
Been touting the Atom on Gearslutz website (music gear/recording). One person says the 0.6dB imbalance between L&R is too high for critical mixing etc. However, this is worse case scenario right? How is the L&R imbalance compared to other headphone amps?
Some get it perfect but most of them have some deviation. One could get around it by setting the volume at max and changing the level upstream.
 

NemoReborn

Active Member
Joined
Jan 24, 2019
Messages
114
Likes
34
yeah, I'd seen that, so according to that graph at many volume knob positions the imbalance will be next to nothing. Not sure how to read the graph with regards to knob position though to avoid the 0.5dB imbalance, but it appears that from 1/2 turned up till about 3/4 one would be getting negligible imbalance?

If u wanna try what chan imbalance really feels like , try some schiit gear ... than ull say the Atom is flawless
 

jaco61

Member
Joined
Jan 26, 2019
Messages
25
Likes
22
I cannot detect any imbalance even in the lowest volume position of my atom. Some much pricier amps had it at very low listening levels... e.g. Ifi
 

Gomjab

Member
Joined
Jan 3, 2019
Messages
37
Likes
48
Can someone help me, how much volume i can reach in dB with my headphone according to https://www.headphonesty.com/headphone-power-calculator/ With a 30 Ohm 98db in sensitivity with Low Gain? Looks like ATOM in Low Gain can reach max 250mw in Amirm measurements, (Tell me if i'm wrong) and i don't get the Vrms story, so don't know.. Maybe 122 dbSPL?
You would get 122 dbSPL if the headphones are rated 98dB at 1mW. If the headphone rating is 98 dB at 1 V RMS the max output would be 106.75 dBSPL.

[EDIT] I ran the numbers using a spreadsheet I have. Looking at your link I see that the website tool has a selection to identify the units. Which 30 Ohm headphones are planning to use?
 
Last edited:

JohnYang1997

Master Contributor
Technical Expert
Audio Company
Joined
Dec 28, 2018
Messages
7,175
Likes
18,292
Location
China
Does anyone know why atom has different volume pot? Why is it the depth? 4 gang? But it's single end amp.
I just ordered one, and thinking of modifying. Will optimize distortion and noise. Mains hum may not look prominent with full out, but it doesn't decrease with volume, so that's a issue. Hopefully I'll get to fix all these. And will do more measurements, square wave, noise when volume pot at noon, full spectrum distortion.
 
Top Bottom