Review and Measurements of New JDS Labs Atom Headphone Amp

[or965]

I having an issue with the atom ,when I adjust the volume on the atom I hear a noise, especially without music playing ,it seem to disappear as I stop adjust the volume . It does not matter if I use the low gain or the high .I use the atom with the topping d50 DAC with 2 RCA to 3.5 mm cable . I also test the same thing with my objective 2 amp with the same cable and it does not have this issue. Can someone test it with his atom amp and tell me if he ear any noise, if you can use a in-ear earphone that you will hear the noise better as it isolate outside noise . ? I want to know if it normal or defect on my unit ?

 

[milw50717]

Just tried with a Modi Multibit (RCA) to Atom (3.5mm) and no noises when I move the volume knob. Listening in a quiet room via Hifiman HE4xx headphones, not in ear units.

Do you hear the sound when you use RCA to RCA cables ?

 

[or965]

@milw50717 thanks you for the fast response but I can not hear it with an over the ear open back headphone,I also test it with my Hifiman HE4xx ,I hear it only with an in ear earphone .I will search for an RCA to RCA cable to test it .

 

[milw50717]

Using some monoprice in ear pieces I hear a slight hiss when the volume is turned all the way up and the gain button is pressed in. The noise disappears altogether when the gain button is in the out position and decreases when the volume is turned down, falling below my hearing threshold at about the 2 o'clock position. No noise is heard just when the volume knob is turned.

Same happens with RCA -> 3.5mm and RCA -> RCA cables

 

[or965]

I just got a response from JDS labs about this issue and they said that it could be that the Topping d50 cause it as this noise can be because of DAC with a DC offset higher then 4mV ,they said that I should immediately disconnect my headphones from Atom Amp until I check what is the DAC DC offset . They said that the DAC DC offset must be below 4mV as the Atom Amp is a DC coupled design . @amirm do you know what is the topping d50 DC offset is, or that can you measure it ? I really does not know what it is and how to measure it ,I also send topping email about it ,maybe they can tell me what is the DC offset of the topping d50.

 

[Gomjab]

I own a Magni. The volume knob looks nice, but the pot is scratchy and has pretty bad channel imbalance below 9 o'clock. The knob is also kind of small which makes it a bit fiddly. The knob on my Atom looks Less premium but works better in practice. I do wish it had a separate power switch though.

I guess I was lucky with my Magni 2 as the volume knob was quiet and balance was fine at my typical listening levels.

I’ve found with the Atom on low gain I can leave volume knob fixed and back volume down with player if needed. This setup is at work and I have the Atom placed a bit out of reach so soft volume control is more convenient. Most of the stuff I listen to only requires a 6dB to 12dB reduction.

I am very happy with the setup.

Audrivana -> Modi3 -> Atom -> Beyerdynamic DT770 (closed) or my HD800s if I know I’ll have office to myself.

 

[ripvw]

After extended listening with the 22 ohm Etymotic ER3SE I can report that they have never sounded better - exceeds performance of NX4 DSD driving the same IEM. No noise, just lots of drive and a silent background - assuming a quality recording. Now I have no excuse for not getting the top-of-the-line 45 ohm ER4SR to add to my limited headphone collection.

I guess that's one more advantage of the DX7S - it was saving me money because I could only use 160+ ohm headphones with it...

 

[bboris77]

I just got a response from JDS labs about this issue and they said that it could be that the Topping d50 cause it as this noise can be because of DAC with a DC offset higher then 4mV ,they said that I should immediately disconnect my headphones from Atom Amp until I check what is the DAC DC offset . They said that the DAC DC offset must be below 4mV as the Atom Amp is a DC coupled design . @amirm do you know what is the topping d50 DC offset is, or that can you measure it ? I really does not know what it is and how to measure it ,I also send topping email about it ,maybe they can tell me what is the DC offset of the topping d50.

It is an interesting assumption on their part. Do you have any other source to try it with? Perhaps hook up your phone to it via 3.5mm jack? Are you 100% sure the amp did not do it with the other DAC? The reason why I am asking is because it is VERY unlikely that your DAC has any DC offset at all, unless it is defective.

Many users including myself have reported the exactly same type of behaviour (whooshing when changing volume with nothing playing) on the Magni 3, which is also a DC-coupled amplifier. This was using a variety of DACs.

This thread also mentioned the same issue: https://www.audiosciencereview.com/forum/index.php?threads/scratchy-noisy-pot-on-the-jds-atom.6311/

 

[or965]

@bboris77 I still with contact with JDS about this and they suggest that I will try connect the earphone to the amp without connecting the DAC to the amp and test it .I test it with no DAC connected and it still has the same issue, after it i tried to use the high gain and adjusting the volume knob to a higher volume and I start to hear buzzing sound .I also tried to connect my phone to the atom and it has the same issues .They really scared me with the first response about damage to my earphones as maybe I just not heard this noise until now because I do not adjusting the volume without music, I only heard it when I play a song which is very quiet at the first 10 seconds and then I decided to check with no music .

 

[or965]

I want to update that JDS think that the issues that i described is not normal and it does not related to the DAC DC offset as the issues appear on different DACs and even without DAC .They will send me a replacement as it seem that the amp is defective .I want to note that the customer service was really good and fast. I will update after I will receive the replacement, but I do not think that there will be any issues with the replacement .

 

[amirm]

Definitely keep us posted.

 

[NemoReborn]

I having an issue with the atom ,when I adjust the volume on the atom I hear a noise, especially without music playing ,it seem to disappear as I stop adjust the volume . It does not matter if I use the low gain or the high .I use the atom with the topping d50 DAC with 2 RCA to 3.5 mm cable . I also test the same thing with my objective 2 amp with the same cable and it does not have this issue. Can someone test it with his atom amp and tell me if he ear any noise, if you can use a in-ear earphone that you will hear the noise better as it isolate outside noise . ? I want to know if it normal or defect on my unit ?

Desktop -> d50 using 2 usb (1data/1power) -> Atom. DEAD SILENT even max volume with high gain or if I move the pot

 

[or965]

@NemoReborn thanks you so much for the response .I already write that it dose not related to the Topping d50 DAC as it happen with other DACs or even without one .

 

[Veri]

I want to update that JDS think that the issues that i described is not normal and it does not related to the DAC DC offset as the issues appear on different DACs and even without DAC .They will send me a replacement as it seem that the amp is defective .I want to note that the customer service was really good and fast. I will update after I will receive the replacement, but I do not think that there will be any issues with the replacement .

It sounds like a noisy pot.

 

[NemoReborn]

It sounds like a noisy pot.

Coming from a schiit fulla 2 , I know what noisy pot soundlike and Yes it really seems to be the case ! Haha. Schiit .... ...

 

[daftcombo]

Hi,

Do you think it would be possible to plug the Atom Headphone Amp straight in the RCA out of a budget CD or DVD player like the Sony DVP-NS330 ?
Those usually have pretty high output.

Thanks,

Thomas

 

[bakker_be]

Hi,

Do you think it would be possible to plug the Atom Headphone Amp straight in the RCA out of a budget CD or DVD player like the Sony DVP-NS330 ?
Those usually have pretty high output.

Thanks,

Thomas

Viewed from a signal flow logic, it would actually be the other way: CD/DVD --> Atom --> Headphone. This should work with no issues at all.

 

[daftcombo]

Sorry for my bad english, that was what I meant.
Thank you!

 

[AresHarvest]

@or965 seems like you've eliminated DC offset as the cause...

But if not, it can easily be tested without an analyzer, if you're still unsure. https://www.parts-express.com/harrison-labs-fmod-inline-crossover-pair-20-hz-high-pass-rca--266-246

 

[kprog]

Hello! Today I received Atom. I use it with DT990pro 250 ohm
But I have lack of volume! It sounds very loud, but I am able to put the volume to the maximum at high gain, without causing me annoyance, it is simply heard loudly, but not very very loud.
Could it be because of the DAC?
I have tried 2 options.

1 Atom connected to the headphone output of my PC. Jack to RCA. Motherboard MSI Gaming plus 370Z ... The sound is too loose, I do not get much power ..

2 Atom connected to the output of my external sound card, RCA to RCA. Sound blaster omni surround ... With this option I have a lot more volume, but I think not enough. my head does not explode! There is even distortion. sometimes at maximum power distorts the bass. pugg puggg puggg

What can happen? none of the 2 DACs have enough voltage to make Atom work well?

rms output voltage of my soung blaster is 1.75 Vrms.

What worries me most is the distortion of the bass, sub bass, on tracks with many sub bass and high volume.
This means lack of power? or does it mean that the headset does not accept more power and starts sounding bad?