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JDS Labs EL DAC II Review

jasonq997

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So I also saw $299 not $249. I still feel like I stole it at $299 from what I am reading. Still inquiring minds. I am just wondering if I should get the EL amp II and retire the atom who is in it’s breaking in period still. Damn I love this hobby but I cannot stop the wheels of progress.

I think you will get aesthetic benefits from the EL amp vs. the Atom. You are unlikely to get any audio benefits.
 

audio_tony

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The resemblance to the old Logitech Squeezebox Duet is quite uncanny. This too had a colour changing LED on the front panel to indicate status.

1574181256806.png
 

Tks

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Not bad. Still not happy about the filter response, but a great implementation of the tried and tested AKM chip nonetheless.

I'm kinda shy about asking as it seems like I am the only person who doesn't know the answer to this. But I've also seen Amir makes comments like these about filter response. But whenever I look at the graphs, it seems to perform great to audible levels. But then again, it seems like I don't even know what I'm supposed to be looking at.

Do you have a spare moment to quickly give me the run down on what a few things mean when Amir says:

Filter response is classic chip default in the way it truncates at 24 kHz rather than 22.05 kHz

What does this actually mean in terms of reprocussions between either. What's the downside of truncating prior or later than 22.05kHz for example?
 
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amirm

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What does this actually mean in terms of reprocussions between either. What's the downside of truncating prior or later than 22.05kHz for example?
Truncating prior could get rid of some of the desired content spectrum. Truncating too late can cause some "imaging" of the audio spectrum, to exist in ultrasonic range. Ideal filter then keeps all the audible band, and none of the ultrasonic above 22.05 kHz. If this is not good enough, I have to dig deeper into signal processing. Do you want me to do that?
 
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Tks

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Truncating prior could get rid of some of the desired content spectrum. Truncating too late can cause some "imaging" of the audio spectrum, to exist in ultrasonic range. Ideal filter then keeps all the audible band, and none of the ultrasonic above 22.05 kHz. If this is not good enough, I have to dig deeper into signal processing. Do you want me to do that?

Ah I understand now, it's basically - how should I call it - "mapping" or "translating" the signal itself within the bandwidth established by the filter. So if it truncated to something ridiculous like 220kHz, that would mean basically everything in the audible range when we would listen to it, would be basically all the sub-bass and bass notes by translation? And all the details beyond 20Khz+ would be inaudible naturally due to headphones and such not reproducing such frequencies (and those that do by chance, do it in vein due to out natural hard-limit of hearing ideal being 20kHz in adolescence as a best case scenario). So we'd basically be only able to hear ~10% of our original audio if it was truncated at 220Khz for example while we played the file back?

I hope I understood that correctly?

Now that I have you, and if you don't mind. These digital filters, are they simply software or something hardware based? Like if a company had an API that can adjust firmware level operations of the DAC chip, would people themselves be able to "make their own" filter. Or is this some sort of silicon-level hardware processes that is set in stone, and making your own would be a question that only makes sense if you were making your own DAC chip itself (which for modern chips I presume would be impossible due to the manufacturing and financial limitations on working with Sigma-Delta chips of this caliber of performance?). What sort of process is it to create a good filter (like what's stopping companies from always hitting the ideal 22.05?) Like for noise and distortion we have a good idea of the factors that come into play that allow for their presence, so I was wondering what sort of thing would be a limitation of a "good" digital filter (I presume one is latency from what I imagine is a problem in the professional field of products).

Oh and just very quickly, is the creation of these filters equal amongst DAC chip varients? Like R2R and such. Is there such a thing as a "analogue" filter of sorts? (Apologies if this question doesn't even make sense to ask).

Thanks again bossman!
 

bequietjk

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I'm not expecting Thanos-like differences but I'm definitely excited to see what The Element II measurements turn out to be.
 
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amirm

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Ah I understand now, it's basically - how should I call it - "mapping" or "translating" the signal itself within the bandwidth established by the filter. So if it truncated to something ridiculous like 220kHz, that would mean basically everything in the audible range when we would listen to it, would be basically all the sub-bass and bass notes by translation? And all the details beyond 20Khz+ would be inaudible naturally due to headphones and such not reproducing such frequencies (and those that do by chance, do it in vein due to out natural hard-limit of hearing ideal being 20kHz in adolescence as a best case scenario). So we'd basically be only able to hear ~10% of our original audio if it was truncated at 220Khz for example while we played the file back?
It will be inaudible but gear is designed without that assumption. Your amplifier will have a much wider bandwidth and my oscillate or use too much power due to all that ultrasonic energy. There are DACs with no filter that run this way but as a mater of proper engineering, we call them broken. :)
 
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amirm

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Now that I have you, and if you don't mind. These digital filters, are they simply software or something hardware based?
Could be both. A set of filters come in the DAC chip which can simply be selected using an external microprocessor. Some let you disable the filter and then you can implement your own. Others upsample the input to something higher and perform such filtering. Most common though is using what is in the chip. When outside of the chip in a DSP or FPGA, they can indeed be upgraded/changed. If inside the DAC chip, then you are stuck with that set. Or the one default provided.
 
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amirm

amirm

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Oh and just very quickly, is the creation of these filters equal amongst DAC chip varients? Like R2R and such. Is there such a thing as a "analogue" filter of sorts? (Apologies if this question doesn't even make sense to ask).
Companies cook up their own versions. And yes, there is analog, and analog+digital filters.
 
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HammerSandwich

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@Tks, sampling can accurately reproduce signals only below half the sampling rate, because there aren't enough samples to describe higher frequencies. That critical frequency acts sort of like a mirror, reflecting higher frequencies back in the opposite direction. Feed a 30kHz sine into a 48k ADC without a filter, and the digital signal looks just like if you'd started with an 18kHz wave. (18 & 30 are the same distance from the 24k Nyquist frequency.)

Too complicated? Think of how wheels reverse directions as cars speed up in a movie: the motion was sampled at 24fps. Same thing.

Here is a page that compares sample-rate-conversion software. There are plenty of examples of poor filtering! Sweeps will show the reflection I mentioned, and the transition graph gives a good view of filter FR. Compare Ableton Live 7 (no filtering?!?) with Sox VHQ (good).

And if you want to play with your own filters, try rePhase.
 
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Tks

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Thank you @HammerSandwich I also use SoX resampler as many folks who've looked at it say it's basically the best barring one other that is proprietary if I recall correctly (but close by a hair). I'm going to give rePhase a try, and see what diffrent filters would sound like, as the ones I've heard on DACs these days all pretty much sound the same to me.

and thanks @amirm For reminding me about the amp portion in this ordeal that logically would mean anything functioning in my hypothetical would be literally defined as busted as it would lead to the amp running signals not reasonably intended.

If either of you know(promise last spam question).. all that we discussed now, does that have any bearing on some weird ringing I hear at times with certain tracks when I set my filter to Non-oversampling? Is this some sort of byproduct? And do most DACs simply disobey this filter setting for this filter if you play a 192Khz or greater file (leading to the prior mentioned silliness of having the amp try and processes these higher frequencies unnecessarily and to perhaps detriment?)
 

Jimster480

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Another interesting review; I kind of expected this to be near the top of the chart given what JDS has done in the past. Its a bit disappointing considering the price although according to the multitone test (closer to real music) it has 20 bits of clear distortion free range? Although linearity is also not perfect...

If this device cost $100 less it would be extremely competitive. JDS is a solid company with actual customer support so possibly its worth the extra $100 to some people?
 

Ceburaska

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We can say we are spoiled with better numbers. :)
Which prompts me to thank you for describing it as “coveted top bracket” rather than “competent”, a much more descriptive term for the blue band.
Having never had a dac that measures better than this, I’d say it is absolutely good enough, but might be a little expensive. However, it is US made and supported, which could have some value.
 

Yuno

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It looks like I am not going to abandon my Khadas Tone Board or my Atom any time soon. The price vs performance for the combo EL AMP/EL DAC
II is too high for what it offers.

On top of this they made the same dumb-ass design choices as with original one. EL AMP II now has nice mode switch that is supposed to allow for easy toogling between headphones and line-out with pre-amp function, and where do they put it? On the back of device again. Who even comes up with this stuff?
But at least it looks nice and minimalistic. They could have removed volume control too, to make it even more minimal.
I don't know, maybe this is what their customer base expects, to me this is example of ridiculous ergonomics design.
 
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