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Review and Measurements of New JDS Labs Atom Headphone Amp

Budwise

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I emailed Topping in December asking a question about USB vs Optical on the D30, they responded within a few days but considering it was over Christmas I think it was fine service. I don't think I'd want to try RMAing something to China though...
 

Bliman

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As a follow up after several weeks of use, I have to say I'm very happy with the Grace SDAC + Atom combo using the HD6XX headphones. Satisfaction without breaking the bank.



View attachment 20084
Grace Design is great. I have a Grace Design m902 for many years now. And I use it as preamp and dac.
A great company with great service. Wish I could get the Grace Design SDac in Europe to.
 

GGroch

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Ghent cables off ebay https://www.ebay.com/itm/321690409603

....FYI the diff between the A01 and A02 cables - apparently the A01 uses Japanese components (per a thread I found on headFi forum).
I share your endorsement of Ghent cables for quality build for cheap. I am using the 1 ft Ghent A02 cables on my D50/Atom with great results. Solid connection at both ends.

I also got some of their A10 cables which are more flexible so less likely to move lightweight components (like the Atom) around. They do not look as impressive...but seem nicely built and soldered, and are quite soft/bendable.

Ghent is my Go-To for RCA Cables as I value quality and cheapness.
 

GGroch

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No such thing exists hehe. Don't let anyone tell you otherwise :D
OK... Let me tell you otherwise

If you look at the photos of the cables themselves in the above references for the Ghent A01 and A02 cables you can see that they both have an external braided metal shield in addition to the ground and signal wires. These shields are only connected at one end so that they reduce, rather than increase RF interference.

In most cases the shields are more effective when connected to the source component, so in the case of the Ghent A01 & A02 the direction arrow should be attached to (pointing away from) the "DAC" side and the Amp to the other end. Because the left & right are two different cables, this also assures that the shields for left/right are connected to the same device. This could potentially reduce RF interference. Note that on my more flexible A10 cable photos...there is no external shield...so there is no arrow.

NOW...to answer your question. Good shielding from a separate mesh shield can be very important in some environments (like in car audio) but is not important in most home setups. I use the flexible not shielded A10 without concern. No arrows needed. The same with the photos of your proposed cable...no arrows because no shield. As far as shielding goes...your cables will probably be fine.

BUT: the biggest issues I have found with cheap RCA type cables are:
1. Poor solder connections at the ends.....so flexing the cable may make the signal cut in and out. and
2. Poor quality RCA connectors, which if they become loose will make the signal cut in and out. Your photos show RCA connectors with a thin outer connection that has a single slit. This type is more prone to be or become loose. This is usually not a problem if you do not disconnect/connect frequently. Plus...if one starts to get loose you can often tighten it with some pliers (or teeth) to make it snug.

Still, I avoid RCA cables that I can see have thin single slit ground connections like the one in your photo. If it is in your budget to get cables with better plugs, I would do it.
 

despoiler

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I unpacked my JDS Atom last night. My signal chain is my computer (Spotify premium HQ, di.fm 320mp3) > iFi Micro iDSD(silver) set in direct mode using GTO filter output via Monoprice premium RCA cable > JDS Atom > Sennheiser HD650. I am using Equalizer APO 1.2 with AutoEQ's profile for the HD650. The JDS Atom is simply stunningly clean. I had an instant smile on my face when I fired up the first track. It's better than using the iDSD's amp powered via battery and far, far better than powering via USB. It is incredible to get the sound quality it delivers for such a low price though I would pay $20 more for a metal case and volume knob. There is nothing more I can say, but I don't think anyone would be disappointed with a purchase.
 
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I share your endorsement of Ghent cables for quality build for cheap. I am using the 1 ft Ghent A02 cables on my D50/Atom with great results. Solid connection at both ends.

I also got some of their A10 cables which are more flexible so less likely to move lightweight components (like the Atom) around. They do not look as impressive...but seem nicely built and soldered, and are quite soft/bendable.

Ghent is my Go-To for RCA Cables as I value quality and cheapness.
Found Ghent cables recently and find them to be of
good quality, at fair prices.
 
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wadec22

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mine just arrived. i'm trying to figure out why they bothered backlighting the volume knob, when you can barely tell there is a light ring there, even in the dark.
 
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Will normal 2RCA-2RCA cables be fine? Without a specified signal direction

Something like that:
I bought blue jeans Lc1 cables because I couldn't find a good price on mogami 2534s. Great sound over my cheaper hosa and Monoprice stuff.
 

pwjazz

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to ppl complaining about non-metal case and volume knob - try Magni 3 :):D
Funny, I'm replacing a Magni 3 with an Atom for these reasons:

1. Volume knob is small and doesn't turn particularly smoothly
2. Pot is scratchy (static noise when changing volume)
3. Measured distortion into low impedance headphones at high power is pretty poor, and it so happens that I need high power into low impedance

Premium looks don't necessarily equal premium quality.
 

Roen

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Funny, I'm replacing a Magni 3 with an Atom for these reasons:

1. Volume knob is small and doesn't turn particularly smoothly
2. Pot is scratchy (static noise when changing volume)
3. Measured distortion into low impedance headphones at high power is pretty poor, and it so happens that I need high power into low impedance

Premium looks don't necessarily equal premium quality.
I'm curious about your point #3.
 

pwjazz

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I'm curious about your point #3.
From Amir's measurements ...

1547165335834.png


Note how right around 2 mW the Magni 3 starts to distort. I use the LCD2C which is a 70 ohm headphone. It's pretty efficient, but between the typical -5dB or so for Replay Gain and my -11 dB pre-gain for my EQ, I'm 16 dB in the hole. Assuming that I want to have headroom to hit 100 dB transient peaks, I'll need 31 mW. We don't have a curve for a 70 ohm load, but I suspect that it's more similar to the 33 ohm load than the 300 ohm load, so likely that's in the territory of the Magni 3's distortion starting to exceed the noise floor. Is it enough distortion to be audible? I have no idea, but since I don't like the ergonomics of the Magni 3 that much anyway, I figure the Atom is worth a shot.

Plus the Atom has dual inputs so I can leave a couple of sources hooked up and switch at the push of a button :)
 
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Got mine on 9th, now waiting for Khadas Tone Board to arrive :)

By the way, when the gain button is released, low gain mode is active, right?
 
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Roen

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From Amir's measurements ...

View attachment 20195

Note how right around 2 mW the Magni 3 starts to distort. I use the LCD2C which is a 70 ohm headphone. It's pretty efficient, but between the typical -5dB or so for Replay Gain and my -11 dB pre-gain for my EQ, I'm 16 dB in the hole. Assuming that I want to have headroom to hit 100 dB transient peaks, I'll need 31 mW. We don't have a curve for a 70 ohm load, but I suspect that it's more similar to the 33 ohm load than the 300 ohm load, so likely that's in the territory of the Magni 3's distortion starting to exceed the noise floor. Is it enough distortion to be audible? I have no idea, but since I don't like the ergonomics of the Magni 3 that much anyway, I figure the Atom is worth a shot.

Plus the Atom has dual inputs so I can leave a couple of sources hooked up and switch at the push of a button :)
While I agree with everything you say, I wonder how audible the distortion at THD+N Ratio of 0.1% is.
 
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Got mine on 9th, now waiting for Khadas Tone Board to arrive :)

By the way, when the gain button is released, low gain mode is active, right?
I have ordered mine on 17th of December, both the Khadas Tone Board as well as JDS Atom.
Neither had come yet.:D
 
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