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Review and Measurements of JDSLabs ODAC Rev. B Compared to Fiio E10K

Grave

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#21
You need to be saying "subjectively" good. Objectively means getting close to a perfect DAC and this one does not. There is no excuse for any high fidelity DAC to spit out a constant tone.
It is audibly perfect and therefore objectively good. Also, NwAvGuy's measurements put the jitter at -103 dB, which is even lower.
 

Ron Texas

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#22
I have a FiiO E10K. After about 6 weeks the power led stopped working. Having not used it in a while, I hooked it up. Output from the line out was around10db less than what it should be. It doesn't drive HD650's because it is broken. This is the risk of Chi-Fi. Fortunately the E10K was cheep enough to be considered a throw away. It sounded good, by the way.

The inability to use 88.2 is in the USB receiver chip used. I believe it is the same one as in the ODAC.
 
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#25
Amirmi! Your reviews are great! Since you are providing Amazon links - consider joining their affiliate program. Many websites exist solely on those programs. You can exist as a hobby for so long...
 

amirm

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#26
Thanks Bravomail. It is very tempting to join the Amazon affiliate but I am resisting it so far to keep my independence.

Then again using that will allow more funds to purchase gear to test......
 
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#27
I have an ODAC and started hearing noise (mostly when moving the mouse) after getting a STAX earspeaker/amp combo yesterday. Interestingly, I wasn't hearing it before with HE-500 headphones plugged into an O2 amp.

Moving the ODAC to another port didn't help. Note that the ODAC is plugged into one of the rear ports, while the wireless mouse receiver is plugged into one of the front ports.

Any ideas?

Thanks
 

maverickronin

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#28
I have an ODAC and started hearing noise (mostly when moving the mouse) after getting a STAX earspeaker/amp combo yesterday. Interestingly, I wasn't hearing it before with HE-500 headphones plugged into an O2 amp.

Moving the ODAC to another port didn't help. Note that the ODAC is plugged into one of the rear ports, while the wireless mouse receiver is plugged into one of the front ports.

Any ideas?

Thanks
You may have to go through several different ports to find one that works. You could also try a USB hub as well
 
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#29
You may have to go through several different ports to find one that works. You could also try a USB hub as well
Is this a common problem with the ODAC? I'm surprised I hadn't noticed it with my previous headphone/amp combination.

Note that this is noise that is easily heard by ear at normal listening volumes. It's not something that you can only detect with one of Amir's fancy analyzers ;)
 

maverickronin

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#30
Is this a common problem with the ODAC? I'm surprised I hadn't noticed it with my previous headphone/amp combination.

Note that this is noise that is easily heard by ear at normal listening volumes. It's not something that you can only detect with one of Amir's fancy analyzers ;)
I never noticed that with my (1st gen) ODAC but all kinds of weird things can occasionally pop up with USB. Reading it over again though, I think it may be the new amp that's picking up the noise.

Do you have another USB DAC to test? Do you hear it now with the HE-500 and O2? Also which model is your Stax amp?
 
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#31
I never noticed that with my (1st gen) ODAC but all kinds of weird things can occasionally pop up with USB. Reading it over again though, I think it may be the new amp that's picking up the noise.

Do you have another USB DAC to test? Do you hear it now with the HE-500 and O2? Also which model is your Stax amp?
I have another ODAC, but the outputs are different (3.5mm vs RCA) and I don't think I have the necessary cables.

I don't think I heard the noise with the HE-500 + O2, but I'll test again this weekend.

My amp is a STAX SRM-323S.

Thanks
 
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#33
OK, I finally figured out what was happening! It turns out I have a ground loop. That's why the noises change when I move my mouse, etc.

The reason I wasn't hearing the noises with my HE-500 was because they are plugged into an O2 amp whose AC adapter only has two pins, so it's not grounded. Instead, my STAX cans are plugged into an amplifier with a 3 pronged power cable (grounded).

How can I get rid of the ground loop? Do I need to get a different DAC which doesn't get power via USB from my computer but instead from a two-pronged (non-grounded) power source? Or would it be enough to buy a non-grounded, powered USB hub and plug it into that?

Thanks
 

maverickronin

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#34
Or would it be enough to buy a non-grounded, powered USB hub and plug it into that?
The hub would still be grounded back to the computer so that wouldn't help unless you got a special transformer isolated one. Your 323S needs to be plugged in to the same outlet/power strip as your computer. If it already is, move the plugs closer together. If they're already in neighboring sockets then you may need some sort of loop suppressing isolation transformer.

Are you sure it's a ground loop though? It's pretty odd that it would modulate with the mouse's movement. That sounds more like radio interference.

A ground loop is usually a constant hum, possibly modulated by moving interconnects and touching the chassis (if grounded) or the input contacts.

Try using a wired mouse too.
 
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#35
The hub would still be grounded back to the computer so that wouldn't help unless you got a special transformer isolated one. Your 323S needs to be plugged in to the same outlet/power strip as your computer. If it already is, move the plugs closer together. If they're already in neighboring sockets then you may need some sort of loop suppressing isolation transformer.

Are you sure it's a ground loop though? It's pretty odd that it would modulate with the mouse's movement. That sounds more like radio interference.

A ground loop is usually a constant hum, possibly modulated by moving interconnects and touching the chassis (if grounded) or the input contacts.

Try using a wired mouse too.
I plugged my PC and amp into neighboring sockets in the same power strip, but the problem persists.

Also, it persists with all peripherals unplugged (including the wireless mouse dongles) and my computer simply sitting at the GRUB prompt (the screen at boot where you choose whether to boot Windows or Linux).

From what I've read online, ground loops can be more than just a steady hum, and often change with mouse movements, non-solid state hard disk head movements, etc:

"Other sounds can be picked up via a ground loop, as well: these include the sounds of your hard drive when its heads move around accessing different files; the scratchy sounds that you sometimes hear when you move your mouse; or those clicks caused by your graphics card re-drawing part of the screen display on your monitor screen."

https://www.soundonsound.com/techniques/solving-computer-audio-problems

Edit: I raised the volume on my amp and there *is* a constant hum as well.
 
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maverickronin

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#38
Yes, 100% It also goes away when I unplug the USB cable from my ODAC.
That's definitely a ground loop then. Not sure what to recommend though.

There are various wall-wart type filters which are supposed to help but I don't have personal experience with any and the listings I remember seeing were short on actual specifications so I couldn't tell you what's likely to work.

Maybe try a different power strip all together or plug both the PC and amp directly into the same wall socket.
 
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#39
Maybe try a different power strip all together or plug both the PC and amp directly into the same wall socket.
Already did and the problem persists :(

Thanks for all the suggestions so far, though! I'm thinking of creating a specific thread for this issue to get more inputs from the rest of the forum members.

My next step is to buy a powered USB hub and plug the ODAC into it.

And the next next step would be to buy a new DAC with its own power supply...

(BTW, I was able to find the 3.5mm/RCA cables needed to try both of my ODACs, and they both exhibit the same problem.)
 
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#40
Solution found! It's not the most elegant thing in the universe, but it's good enough until I get a better DAC.

At first, I was connecting my amp to the ODAC's 3.5 mm output with an RCA to 3.5 mm cable, and the noise was pretty bad.

The breakthrough came when I realized that the noise disappeared as soon as I touched the amp's ground plug with the ground of one of the RCA outputs on the DAC.

I then connected the amp to the DAC's RCA outputs with RCA to RCA cables, which decreased the noise, but not enough.

The final step was to solder a cable to the ground of one of the DAC's RCA sockets, then insert the other end of the cable into the amp's ground plug.

All noise is pretty much gone unless I turn up the amp's volume to ridiculous (unlistenable) levels and start doing certain things on the computer (e.g., stress the CPU, select and deselect multiple files with the mouse back and forth).

Below is my masterpiece :p

20181027_185725.jpg 20181027_185735.jpg 20181027_185825.jpg
 
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