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JDS Labs Atom DAC Review

MC_RME

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#61
As @Tks already mentioned, RME uses AKM DACs which for some Velvet Sound reason, use the same filter set for both 44 and 48kHz material, which is not optimal for the former.

Let me say it as I understood this statement: the AKM chips do not scale the filter cut-off frequency with sample rate. That is wrong. Measuring at 44.1 and 48 kHz gives two different results, in both frequency response as well as the above noise based out-of-band measurement.

AKM SD Sharp @ 44.1 and 48 kHz.png
 
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gvl

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#63
Filters are determined by the DAC chip
You can have an additional onboard filter of any characteristics upstream of the DAC chip, but not in a $99 device. What you can do however is to filter before the DAC in software and feed it with the signal at the max sampling rate it supports, this should bypass the internal filter. How well this will translate into overall technical performance is unclear.
 

KR8NUX

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#65
In other words, the performance is perfect with respect to its purpose. Or do you not intend to use it for listening?
From an era when the Atom amp was a trendsetter, to now where competition like the E30, SK mk2 and other AK4493 solutions exist, yes, price doesn't match performance.
It's like saying an older CPU like the 3770k is the same as the 9700k. Yes, the older is still enough for most purposes but it doesn't mean the newer one isn't better. Whether you can actually 'notice' there difference was never mentioned in my comment.
 

KR8NUX

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#66
Thanks, everyone. It's refreshing to read feedback free of nonsense.

Initial demand for Atom DAC is strong and inline with our forecasting. I've had the same concerns about TOSLINK and market direction peering into the future.

TOSLINK contributed to the long release cycle (and COVID disruptions consumed another 6 months). I ditched the idea of copying and pasting an S/PDIF controller from our other designs and found a better way, in theory. I wanted to hold out for TOSLINK in this release, but with 80%+ of JDS Labs customers only using USB input, we chose to release a bit late, rather than extraordinarily late.
John if the phasing out of the 4490 is true, will you update it to the 4493 over time ? Is there a large BOM difference between the two?
 

PuX

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#67
Typical DACs in this category are just USB powered. This one comes with the standard AC transformer JDS ships with their other products. It is not an issue for performance but I would think it is a cost that could have been optimized.
they believe external power has its advantages.

might help with dirty power or insufficient power (let's say you connect it to raspberry pi that has 2.5A total and has a few things connected besides the DAC).
 

3125b

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#69
to now where competition like the E30, SK mk2 and other AK4493 solutions exist, yes, price doesn't match performance.
But do these other offerings really perform better, and if so, in a meaningful way? I don't think so.
They do however offer a lot more features, a nicer case and a less cumbersome power supply.
they believe external power has its advantages.
True, on the E30 using a USB power supply vs USB hub makes a small (measurable) difference of something like 2dB SINAD as was shown in that thread.
But the thing is, that a USB charger is small, whereas the transformer of the Atom is a hefty thing, heavy and so large that it blocks the two outlets right next to it also (of the European style at least). I could barely fit it in the cable tray of my desk and see that it could be problematic in some instances.
It needs to be so large since a transformer operating at mains frequency needs to be much larger than the one operating at very high frequencies in a switching power supply with the same power rating.
I suspect they do that to ensure consistent performance since that makes it impossible for the user to use a sub standard power supply (or in case of an amp, to overload the PC USB outputs). But then again, in case of the E30, even a noisy USB power supply doesn't seem to hurt it too much.
 

Robbo99999

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#70
Let me say it as I understood this statement: the AKM chips do not scale the filter cut-off frequency with sample rate. That is wrong. Measuring at 44.1 and 48 kHz gives two different results, in both frequency response as well as the above noise based out-of-band measurement.

View attachment 68404
Ok, so the filter is equally suited to both 44.1kHz and 48kHz material....I think that's what you're showing there?
 

kn0ppers

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#73
Yes. Might be SiTime MEMS oscillators. They usually come in plastic packages. You can look up SiT8208, they are commonly used in XMOS digital audio implementations.
 

gvl

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#74
Excuse my OCD folks, but the Atom DAC's outputs don't line up vertically with the Atom amp's RCA inputs.
 

phrosty

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#75
I'm in for one :). It will stack well with my Atom Amp to replace my ODAC.

It doesn't win the numbers race, but it's transparent so that doesn't matter to me. I think JDS is one of the best audio companies around right now in terms of build quality, support, openness, and dedication to objective results. They're worth supporting.
 

Jimbob54

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#76
Excuse my OCD folks, but the Atom DAC's outputs don't line up vertically with the Atom amp's RCA inputs.
I dont know by how much, but you've hit on a bugbear of mine. Can we not all agree that source outputs should be on the same side as matching format receiving inputs? Always assume vertical stacking not horizontal placing. See also "innovative" speaker connections.
 

imagidominc

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#77
It's about time this came out! This will be the stack that I will be recommending anyone who wants to dip their toes into DACS/Amps.
 

gvl

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#78
Is a combo device with variable outputs a possibility? I don't really need 2 boxes sitting on my desk and 2 transformers blocking half of the extension strip under the desk. Should help with the weight too.
 
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Jimbob54

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#79
Is a combo device with variable outputs a possibility? I don't really need 2 boxes sitting on my desk and 2 transformers blocking half of the extension strip under the desk.
My thinking is , of course its possible, but the company that introduces a $120-$150 dac/amp combo with the performance of this or similar stack is cutting a huge chunk out of its own margins . Unless they get market saturation in an already nearly saturated market, why bother?

( This answers my own question from a few posts ago)
 
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#80
Ah, so basically any device that can be connected via Coaxial and Toslink can be connected via the USB input and I won’t be limited in terms of what devices I can connect the atom DAC to?
I use as primary sources on my main systems a BlueSound Node 2 or Vault 2 for streaming and various CD transports (for my obscure discs I’m too lazy to rip onto the Vaults). None of them have USB outputs, but only S/PDIF Coaxial and TOSLINK so I have to have at least one of those or it is useless for me in these systems. Since most people using these small devices seem to use them on the desktop, often with headphones, it appears to be assumed that they will be fed from the user’s PC and the other inputs are unnecessary. Such setups do not work for me for most of my listening.
 
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