Review and Measurements of Topping DX7s DAC and Headphone Amp

[DonH56]

Most any DAC should drive powered speakers or a power amp. You'd want to make sure it has a volume control you can live with (e.g. a remote for most of lazy bums who don't walk across the room to change the volume, or have it close at hand on your desk) and of course you give up the flexibility of a preamp (which may not matter).

 

[TheInquiring]

Thank you, dear experts!

@RayDunzl: what if a power amplifier has input impedance out of the range of 10k - 100k? Like Medusa, e.g.?

P.S. I am so happy I found this very informative, and unbiased forum! Believe it or not, I almost got myself into a pile of Schiit...

 

[DonH56]

Input impedance is usually only a problem if it gets too low. >100k is not a big deal.

 

[johan]

All tests unless noted were with the default Brickwall filter. The power supply is built in and is linear.

Hi Amir

THD+N measured here is A weighted ?

 

[amirm]

Hi Amir

THD+N measured here is A weighted ?

Hi Johan. Good question. No, there is no weighting. The THD+N measurement is versus frequency so in that context, it would not make sense to apply a-weighting to it. We can visually do that ourselves though, putting more emphasis on mid frequencies and less at the high and low end of the spectrum. I have been doing that in some of my verbal commentary.

 

[johan]

Do you know how many uV of noise is the N in THD+N at 1 Khz lets say ?

The numbers seems unusually high. In my base system with EVM from Ess Sabre I have it at 12uVrms.Do you have it at less than 3 ?

The only thing I can assume its that they used a DC blocking caps in the signal...great for thd+n but not for sound. I might be wrong though..

 

[amirm]

Do you know how many uV of noise is the N in THD+N at 1 Khz lets say ?

THD+N analyzer works in db or percentage of the original tone. I will have to measure the original tone to know what its amplitude was to compute the relative voltage to it.

The numbers seems unusually high. In my base system with EVM from Ess Sabre I have it at 12uVrms.Do you have it at less than 3 ?

High where? In the THD+N relative to frequency graph?

 

[johan]

Yes THD+N vs frequency . I am not suggesting your data is wrong .

I have an EVM from ess sabre , with a THD+N (tested by ess) vs frequency that shows -114 THD+N (1Khz) vs all types of frequency (almost flat)

Same board we took and tested with smps psu (rather clean) at 1Khz a weighted and we got no more than -102db

I am wondering if you do the same test , if you will be able to see the same thing.

 

[amirm]

I post that measurement sans the computation of THD+N in my original review:

The third harmonic is at -113 dB or so. Adding up the first few taller spikes nets in at -111 dB.

Seeing how chip companies do their best to get the best numbers they can get, above is close enough to what they are saying.

Note that the above is much more accurate than any THD+N meter in the way we can eliminate noise and only look at THD.

 

[shawndo]

So how does one actually buy one of these dx7s dacs in the US. Are ebay and aliexpress the only current options? (other than waiting for massdrop to come around again)

 

[amirm]

I see it on Amazon right now: https://smile.amazon.com/dp/B07B4VF...p-feature-scomp-wm-4&ref=bit_scomp_smile_sav0

 

[shawndo]

nice, don't know how I missed that lol.

 

[gab]

I reached out to Topping sales about the remote for the DX7s.

Their reply was: "The remote will be sold as a single item in May."

Good news for those of us who need a remote and don't want to futz with a universal remote.

gab

 

[amirm]

That is good news. Thanks for checking and welcome aboard!

 

[gab]

I was reading a review on the DX7 here: https://www.soundphilereview.com/reviews/topping-dx7-review-1149/

What bothered me reading this DX7 review was this statement: "When “Line Out” mode is selected, the output goes to every connected device – in my case, I connected the Little Dot MKIII SE to the balanced outputs and the Creative T30 Wireless powered speakers to the RCA outputs. There was no way to select the desired output, so I could not switch between them. There’s also no way to adjust the volume when in line out mode, so it does not really act as a preamp."

Although the review was on the DX7, I am assuming the DX7s would operate in a similar manner. I was hoping to use the balanced outputs on the rear panel of the DX7s directly into my amp (without an external preamp to control the volume) but is it true the volume control in the DX7s (via either the soon to be available remote control or the front panel control) only controls the headphone amplifier output and not the level going to the balanced output on the rear? What a shame if this is indeed true as it won't work in my setup. Anyone own a DX7s and know about this? Thanks

gab


EDIT: I just saw this comment on this site: https://www.shenzhenaudio.com/toppi...sb-full-balanced-dac-headphone-amplifier.html

"Can I change the RCA output level with the volume knob? I want to use this product like a preamplifier." The response was: "Dear Ao,on the headphone amplifier+DAC mode.Thank you."

So maybe it will do what I need it to. Fingers crossed!

 

[amirm]

Looks like he didn't read the manual. The device works in three modes: DAC-only, Headphone-only and Headphone+DAC. Double clicking the front knob changes the mode and with it, whether the volume control acts on the rear line outs, or not. Indeed I have used it to drive my active speakers directly using the volume control and it works perfectly.

 

[gab]

Amir - so if you just want to use it as a DAC/Preamp (no headphone) and tie it directly to either an active speaker OR an amp (same thing really unless the active speaker controls the volume) and use the Remote control to control volume, what of those 3 modes do you select? I assume "DAC- only", but since you have one and I don't....Thanks for the reply and this is startig to look like it will do what I need it to in my setup.

gab

 

[amirm]

Here is the operation in the three different modes:

1. Headphone: RCA mute, volume control for headphone
2. DAC: headphone mute, Fixed RCA with no volume control
3. DAC+HP: headphone and RCA both on, volume control on both

Note that while the multi-mode control on the unit has to cycle through the above three modes, the remote has three distinct buttons to instantly select each: "headphone symbol," "Line Out," and "Headphone Symbol+Line Out." So this lets you nicely control whether you want your active speakers to play together with the headphones or not while having full use of volume control (or not).

 

[Jimster480]

Here is the operation in the three different modes:

1. Headphone: RCA mute, volume control for headphone
2. DAC: headphone mute, Fixed RCA with no volume control
3. DAC+HP: headphone and RCA both on, volume control on both

Note that while the multi-mode control on the unit has to cycle through the above three modes, the remote has three distinct buttons to instantly select each: "headphone symbol," "Line Out," and "Headphone Symbol+Line Out." So this lets you nicely control whether you want your active speakers to play together with the headphones or not while having full use of volume control (or not).

And even if you use the wheel itself, it actually "winds" the volume up so even if you have a high volume setting you wont be deafened by accidentally swapping the mode. Its actually quite nice since I have done it a couple times xD

 

[Disruptor]

And even if you use the wheel itself, it actually "winds" the volume up so even if you have a high volume setting you wont be deafened by accidentally swapping the mode. Its actually quite nice since I have done it a couple times xD

Hey, could you explain this to me how it works?
Lets say im listening to my headphones at 50% volume what happens if i switch to the 3. mode? will my jbl 305 blast music at 50% as well or does the dx7s reset the volume (mutes it) and i have to turn the knob from 0 dB to my desired volume