Review and Measurements of New JDS Labs Atom Headphone Amp

[rendyG]

Is there a way to make Atom feed pre-out without it being powered on all the time?
I don´t think leaving it on the whole afternoon (either feeding to headphones or speakers) a day is good for it...
Or am I wrong? I was used to Fiio K5´s line out working even when it was off..

 

[JohnYang1997]

I just got this thing and did some measurements. It seems like it's improved from el amp. Especially the previous high frequency low impedance load distortion.

There are still two things to improve here.
Lower impedance distortion eg 8 ohm at 6500hz.
High gain distortion without load at 6500hz.

Will try changing some resistor values first then I'll change the opamps.

But the question is.....
Does anyone know how to disassemble this thing?

 

[JohnYang1997]

Is there a way to make Atom feed pre-out without it being powered on all the time?
I don´t think leaving it on the whole afternoon (either feeding to headphones or speakers) a day is good for it...
Or am I wrong? I was used to Fiio K5´s line out working even when it was off..

It doesn't matter. Just leave it on forever.

 

[bakker_be]

I just got this thing and did some measurements. It seems like it's improved from el amp. Especially the previous high frequency low impedance load distortion.

There are still two things to improve here.
Lower impedance distortion eg 8 ohm at 6500hz.
High gain distortion without load at 6500hz.

Will try changing some resistor values first then I'll change the opamps.

But the question is.....
Does anyone know how to disassemble this thing?

If I wanted to disassemble it, I'd remove the little rubber feet first. Seems like a logical place to hide screws ...

 

[JohnYang1997]

If I wanted to disassemble it, I'd remove the little rubber feet first. Seems like a logical place to hide screws ...

Sure but the bottom seems to be a single unit. The top looks really like something to pop off. But i am a bit scared to break things. Just like last time I broke the potentiometer on the el amp. And couldn't get the broken part off of the big knob.

 

[JohnYang1997]

Ok thanks the screws are screwed on to the top.

 

[JohnYang1997]

Modification done.
Modifications:
Changed opamp to opa2156

Changed 1k and 3.3k resistors at feedback network to 220ohm

Changed volume potentiometer to bourn 1kohm

Cosmetic change: the original volume pot used D shaft, not compatible. Adopted the original o2's pot cap.

Performance change: lower THD at high gain. Lower noise. (really no other performance change eg: loaded thd at low gain)

Subjective change (This is all in my head and not really happened!)

Original atom sounds energetic and pushed out. Both ends are not well extended or controlled. Can be a little bit veil and thick. Little bit congested in the mids. Soundstage is very wide so that's good.

After modification, the change is made to the whole spectrum. Bass is tighter fuller but more controlled, less thick and more forward. Imaging is better, clearer and more stable. Highs are a bit more cleaner and clearer. Not really more highs but you can hear more clearly. Transparency is better. Mids are more controlled but now has a bit of glossy type of sound, very smooth.

At the end: if you believed me, please dial the difference to the minimum you possibly can. The differences are subtle but consistent.

Thanks.

Edit: one this really annoyed me was that the volume pot is balanced only after 10 o clock. New pot balanced after 8 o'clock.

 

[Biblob]

Modification done.
Modifications:
Changed opamp to opa2156

Changed 1k and 3.3k resistors at feedback network to 220ohm

Changed volume potentiometer to bourn 1kohm

Cosmetic change: the original volume pot used D shaft, not compatible. Adopted the original o2's pot cap.

Performance change: lower THD at high gain. Lower noise. (really no other performance change eg: loaded thd at low gain)

Subjective change (This is all in my head and not really happened!)

Original atom sounds energetic and pushed out. Both ends are not well extended or controlled. Can be a little bit veil and thick. Little bit congested in the mids. Soundstage is very wide so that's good.

After modification, the change is made to the whole spectrum. Bass is tighter fuller but more controlled, less thick and more forward. Imaging is better, clearer and more stable. Highs are a bit more cleaner and clearer. Not really more highs but you can hear more clearly. Transparency is better. Mids are more controlled but now has a bit of glossy type of sound, very smooth.

At the end: if you believed me, please dial the difference to the minimum you possibly can. The differences are subtle but consistent.

Thanks.

Edit: one this really annoyed me was that the volume pot is balanced only after 10 o clock. New pot balanced after 8 o'clock.
View attachment 23190View attachment 23191

My turn.
Very nice to see your mods. But to claim it sounds better might be very much due to expectation bias. Especially the description and the fact you say it is a bare minimum improvement, confinces me to believe it's probably because a differrence between the ears than the sound coming out of the amp.
It would be nice to confirm your assumption by blind testing and/or measurements. Also because the fact that the Atom the fact that already measures very well.

Please let's not turn this thread in the same as what the DX3 has become.

 

[Deleted member 3566]

Guy was being sarcastic...

 

[Biblob]

I cannot really comment on that because is depends on your perspective and the way how you read the message. Or maybe I'm not seeing something, which could be true ofcourse.
Either way, it's about the bigger picture

 

[elira]

Modification done.
Modifications:
Changed opamp to opa2156

Changed 1k and 3.3k resistors at feedback network to 220ohm

Changed volume potentiometer to bourn 1kohm

Cosmetic change: the original volume pot used D shaft, not compatible. Adopted the original o2's pot cap.

Performance change: lower THD at high gain. Lower noise. (really no other performance change eg: loaded thd at low gain)

Subjective change (This is all in my head and not really happened!)

Original atom sounds energetic and pushed out. Both ends are not well extended or controlled. Can be a little bit veil and thick. Little bit congested in the mids. Soundstage is very wide so that's good.

After modification, the change is made to the whole spectrum. Bass is tighter fuller but more controlled, less thick and more forward. Imaging is better, clearer and more stable. Highs are a bit more cleaner and clearer. Not really more highs but you can hear more clearly. Transparency is better. Mids are more controlled but now has a bit of glossy type of sound, very smooth.

At the end: if you believed me, please dial the difference to the minimum you possibly can. The differences are subtle but consistent.

Thanks.

Edit: one this really annoyed me was that the volume pot is balanced only after 10 o clock. New pot balanced after 8 o'clock.
View attachment 23190View attachment 23191

Did you add the weights?

 

[JohnYang1997]

Did you add the weights?

Are those rubberish thingy weights? Oh that's the weight my friends were talking about. No that wasn't me. Tbh it's still quite light and cheap feeling. It could be much smaller.

 

[elira]

Are those rubberish thingy weights?

Yes, like the ones used to balance car wheels. I thought you added them to make it heavier.

 

[JohnYang1997]

Yes, like the ones used to balance car wheels. I thought you added them to make it heavier.

I think jds added them.

 

[amirm]

Did you add the weights?

They come with weights.

 

[tired_guru]

Even then, It was a tad cheaper to import it directly from USA in my case (Poland).

£109+£19 (shipping) = $169.11 and then you would have to get a plug adapter (They're shipping with the UK plug only and I needed the EU one) for another £5 = $175.75

$137+$137*19% (VAT) = $163 without additional costs.

Your calculations are not correct.

VAT is 23%, not 19%. Just had a look at my customs clearance papers from the post office. And there will be some small costs added, because of extra documents that need to be filled out too.

Also take into account that you have like no warranty when buying from USA. Having it locally in EU would be much easier & cheaper to send it back for repair if needed.

Don't even mention that I had to wait for mine 1,5 month. From UK I would probably get it within one week. So this is simply not comparable.

I also got mine from USA because I wanted to have it as soon as possible (none of EU dealers had it then), and knowing how good is QC & design of JDS I decided to be risk taker here.

 

[Reyer]

Your calculations are not correct.

VAT is 23%, not 19%. Just had a look at my customs clearance papers from the post office. And there will be some small costs added, because of extra documents that need to be filled out too.

Also take into account that you have like no warranty when buying from USA. Having it locally in EU would be much easier & cheaper to send it back for repair if needed.

Don't even mention that I had to wait for mine 1,5 month. From UK I would probably get it within one week. So this is simply not comparable.

I also got mine from USA because I wanted to have it as soon as possible (none of EU dealers had it then), and knowing how good is QC & design of JDS I decided to be risk taker here.

Thing is that initially I believed that VAT is 23% here but somehow for 2 different electronic items ordered from USA I've been charged 19% for both. Dunno why tho.

 

[Veri]

Tax can often be very, very random and up to the whims of whatever clerk is doing the processing...

 

[tired_guru]

Thing is that initially I believed that VAT is 23% here but somehow for 2 different electronic items ordered from USA I've been charged 19% for both. Dunno why tho.

I guess you're just the lucky one But it's not a big deal though.

 

[la2ygoo]

Why low gain better in high level , high gain better in low level , and both stop in 2Vrms?
Is this 2Vrms mean input？so it is 9Vrms output?