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Review and Measurements of Topping DX7s DAC and Headphone Amp

Toku

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The following is my simple doubt.

Is the headphone output impedance of DX7s as high as 10Ω or more because it uses the TPA6120A2 headphone amp chip?
TPA6120A2 chip is used in many other products. Do these products have the same high output impedance?
The product explanation proudly explains the use of TPA6120A2.
When checking the data sheet of TPA6120A2, the output resistance is described as 13Ω (min).
I wonder why this chip is designed to have such a high output impedance. Is it for output protection?
Are there other major benefits of using TPA6120A2?
 

Dana reed

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Not sure on the how the specs for the amp chip correlate to the required output impedance of the DX7s, but here is where I saw the specs online
http://en.tpdz.net/wdzn_detail/newsId=73.html
The main concern for me would be on some lower impedance headphones with non-flat impedance curves (like my favorite Grados).
 

Grave

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20 ohms is a bit high for the balanced output.

10 ohms is fine for my headphones.

I guess I will stick with my D30/A30.
 

cheungtsw

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Can I use the DX7s as pre-amp with a poweramp like Optoma NuForce STA200 Power Amplifier?
 

Toku

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Can I use the DX7s as pre-amp with a poweramp like Optoma NuForce STA200 Power Amplifier?
You can switch between preamplifier mode and fixed output mode. I am also directly connected to a power amplifier that can not handle volume.
 

Dana reed

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I got my DX7s a couple weeks ago, and have been pretty happy with it so far. Based on lots of the measurements here, I wanted to do some blind listening tests between this DAC and a multibit one with inferior measurements. I have a Gugnir multibit and a passive balanced preamp so I can ABX the DX7s and Gugnir being fed the same stream. The output from the DX7s was generally ~3 dB higher than the Gugnir even though both list 4V out on the XLR outs. So I ran the DX7s at -3.0 dB to read back the same output level using a test tone and just a dB meter in the room, adjusting until I got the same level
I had someone else do the switching and then I would try to pick which was which, and also whether I preferred one or the other. I used some of my favorite albums (Tool Lateralus, Clapton Unplugged, Pink Floyd Wish you were Here, Dire Straits Brothers in Arms).
We skipped around to favorite tracks and would play about the first two minutes of a track starting with DAC A or B, then repeat again with the other, and then randomly pick one of them for X.
Bottom line is that I failed to distinguish them. I got pretty nearly the statistical probability of 50%. And honestly while listening I was having trouble picking out any differences in details between A and B.

Since then I moved the DX7s to my headphone setup at my desk at work, and left the Gugnir in the living room for the 2-channel setup. The DX7s does a good job with most of my headphones, but has to be pretty much turned all the way up for the HE560 and the DT880 600 Ohm. For those ones I prefer the Magni. I haven't compared closely between the DX7s and Magni with my Grado GS2000e to see if there's some frequency response change from the higher output impedance on the DX7s, but there's nothing obvious to note.
 

ABQdude

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Mac user here on iMac and DX7s for over 3 months. I have had the same problems as @rickymiester and @mi-fu, and mi-fu's solution has worked for me also. I will watch with interest if Topping has any reply to rickymiester's inquiry.

I also wanted to report on interesting findings on using Audirvana and HQPlayer/Roon on the DX7s via USB on an iMac. My music library is mostly ALAC 44.1/88.2/96/176/192. On Audirvana Plus (latest version) I can get PCM upsampled to 705/768, but I get dropouts and clicks at that setting. PCM upsampled to 352.8/384 works fine and sounds very good. On DSD upsampling of PCM files, I can get to DSD256 but again I get clicks and dropouts. No such problems when upsampled to DSD128. On the DX7s in Audirvana Plus upsampled to DSD128, I get strong sibilance on female vocalists, but less so on PCM 352.8/384.

Using HQPlayer/Roon on the DX7s, I can easily upsample PCM to705/768 and DSD256 (the max available on a Mac) without any dropouts or clicks, and no sibilance. So as much as I have been a happy and long-time Audirvana user, I now use HQPlayer/Roon and upsample all my music to DSD256. The sound is quite nice to my ears using my music and desktop system, Paradigm MilleniaOne CT active speakers and SennHD650 balanced into the DX7s. The HQPlayer/Roon combo seems to be a synergistic pairing with the DX7s. Very nice indeed.

Just to update my earlier report, on the latest version of Audirvana Plus I can upsample all PCM to 705/768 and DSD 256 without any dropouts or clicks/pops. Nice!
 

mi-fu

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Just to update my earlier report, on the latest version of Audirvana Plus I can upsample all PCM to 705/768 and DSD 256 without any dropouts or clicks/pops. Nice!

Actually do I need a PC to update the firmware of DX7s? It seems that it doesn't offer a firmware update for Mac. Or did I miss something??
 

ABQdude

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Actually do I need a PC to update the firmware of DX7s? It seems that it doesn't offer a firmware update for Mac. Or did I miss something??
Yeah, I couldn't see any way to do it in macOS High Sierra since the updater is an exe file. I used Parallels 13 with a Windows 10 virtual machine and it all went well.
 

mi-fu

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Yeah, I couldn't see any way to do it in macOS High Sierra since the updater is an exe file. I used Parallels 13 with a Windows 10 virtual machine and it all went well.

argh!!!!! :eek:

I gotta find a way to get a PC to do it then!!

Thanks for the info!!
 

Sal1950

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argh!!!!! :eek:

I gotta find a way to get a PC to do it then!!

Thanks for the info!!
Ya, we all hate when we have to stick our toes in the Windoz world, makes me feel so dirty. o_O
 

bakker_be

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Apple is crap. :p
No it isn't. Much as I dislike all things Apple, the intrinsic quality of their product can't be denied. Where I draw the line is their way of dumbing it all down towards the common denominator ...
If I need my hand to be held I'll ask for it, nobody has to decide that in my place :p
 

Sal1950

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Apple is crap. :p
Don't know anything about Apple except the ones you eat.
I'm a Linux guy and feel that anything besides Windoz is a big step up.
Friends don't let friends do Windoz :p
 

mi-fu

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The raison d'être of all machines is to irritate human beings. I learnt to accept that. :facepalm:
 

Sal1950

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