Topping DX7 Pro DAC and Headphone Amp Reviewed

[JohnYang1997]

Here. So it's kind of distortion but ultrasonic anyway.

 

[amirm]

To address/clarify this issue (i.e, The DAC is great but the headphone amp section not so much), @amirm, could you an appendix to this review that evaluates the headphone amp performance in the context of other headphone amps, including the SOTA competition?

It is less powerful and has higher output impedance than top of the line amps.

 

[amirm]

View attachment 36490
Here. So it's kind of distortion but ultrasonic anyway.

Correct. Did not show up as anything significant as far as intermodulation distortion in audible band.

 

[dmac6419]

I am going to use it for my everyday unit. You have to decide for yourself.

Thanks

 

[blabka]

If your headphone has an impedance curve that is a) less than 60 ohm and b) is not flat, then its frequency (for better or worse) may change a bit.

Headphone Listening Tests
I started with my very low impedance (25 ohm) closed back Drop Mrspeakers Ether CX using XLR "balanced" headphone output. In high gain the DX7 Pro had no trouble pushing these headphones to skull resonating level. These are tough to drive headphones but despite that, there was no issue whatsoever in driving them to get maximum bass punch, detail and fidelity.

Does DX7Pro output impedence not matter with Ether CX cause planar magnetic headphones have flat impedence curve?

 

[veeceem]

So I'm about to match DX7 Pro as DAC+preamp to a power amp (Cambridge Audio Edge W)
What I read: "
When matching preamps to power amps, a general rule of thumb is for the load (amp) input impedance to be at least 10 times higher than the source (preamp) output impedance to provide a suitably flat frequency response. Many prefer using a minimum ratio closer to 20 to 1, or having an amp with input impedance 20 times or more greater than the preamp output impedance."

I go to power amp website and read its specs, which states:
INPUT IMPEDANCES
Input A3 (balanced) 47k Ohm; Input A1-A2 (unbalanced) 47k Ohm

But I can't find the output impedance of RCA/XLR outputs on the topping website, can someone points this out? Thanks.
(I do find info of the output impedances of RCA/XLR on drop.com, but then I suspect, where did drop.com get the numbers when they're not stated on topping website)

 

[PaulD]

The OP impedance will be less than 20 times lower than 47k Ohm, probably about 100 Ohms. It uses a high quality Op Amp to drive the outputs, an LME49720 if I recall, which will have some small resistors on the output to isolate the cable capacitance, probably somewhere between 10 Ohms and 200 Ohms. It will work fine, it's a non-issue.

 

[Veri]

Nice to see that your graphs turned out virtually identical to those that Topping put on their website:

http://www.tpdz.net/products_detail/productId=44.html

However Topping managed to show a slightly better THD+N ratio (below 0,0001%) and thus a slightly higher SINAD. From their graphs design it is obvious that they have used the same model of AudioPrecision that you do, so what could explain the difference? Random quality fluctuations in DAC/analyzer? Better cables?

A-weighting.

 

[Schackmannen]

Nice to see that your graphs turned out virtually identical to those that Topping put on their website:

http://www.tpdz.net/products_detail/productId=44.html

However Topping managed to show a slightly better THD+N ratio (below 0,0001%) and thus a slightly higher SINAD. From their graphs design it is obvious that they have used the same model of AudioPrecision that you do, so what could explain the difference? Random quality fluctuations in DAC/analyzer? Better cables?

Their measurements are A-weighted.
Edit: Veri beat me to it

 

[amjosh]

Hey @amirm , just sold my D50 (original version). Could not keep it after seeing those gross plots of ESS hump . Just could not make peace with it, even if I knew I am not going to be able to sense the difference audibly. Now, I am in real dilemma, whether to buy the D50S or DX7 Pro or just go with D70. I have Massdrop THX 789 as amp, so that is taken care of.

 

[veeceem]

Hey @amirm , just sold my D50 (original version). Could not keep it after seeing those gross plots of ESS hump . Just could not make peace with it, even if I knew I am not going to be able to sense the difference audibly. Now, I am in real dilemma, whether to buy the D50S or DX7 Pro or just go with D70. I have Massdrop THX 789 as amp, so that is taken care of.

Iirc, I read somewhere that matrix element i is about to be released with streaming capabilities $999 Iirc

 

[Veri]

Hey @amirm , just sold my D50 (original version). Could not keep it after seeing those gross plots of ESS hump . Just could not make peace with it, even if I knew I am not going to be able to sense the difference audibly. Now, I am in real dilemma, whether to buy the D50S or DX7 Pro or just go with D70. I have Massdrop THX 789 as amp, so that is taken care of.

Consider E1DA 9038s, no hump and dirt cheap or upcoming single ended variant.

 

[JohnYang1997]

Nice to see that your graphs turned out virtually identical to Topping’s own graphs:

http://www.tpdz.net/products_detail/productId=44.html

However Topping managed to extract a slightly better THD+N ratio (below 0,0001%) and thus a slightly higher SINAD. From the look of their graphs I assume that they have used the same model of AudioPrecision as you do, so what could explain the difference? Random fluctuations in measurements/DAC/analyzer quality? Better cables?

A weighted also APx555B.

 

[dropbear]

I was somehow hoping for an extra ~1W to 50Ohm from headamp...it could be then an endgame AiO (like real AiO, DAC, pre-amp, remote, headamp) for everyone, not even THX would seem necessary.

 

[RickSanchez]

It uses a high quality Op Amp to drive the outputs, an LME49720 if I recall ...

Correct. (Full view here.)

 

[MediumRare]

INPUT IMPEDANCES
Input A3 (balanced) 47k Ohm; Input A1-A2 (unbalanced) 47k Ohm

But I can't find the output impedance of RCA/XLR outputs on the topping website, can someone points this out? Thanks.
(I do find info of the output impedances of RCA/XLR on drop.com, but then I suspect, where did drop.com get the numbers when they're not stated on topping website)

DX7 Pro output impedance at XLR is not reported but DX7 was 200 ohms http://www.tpdz.net/products_detail/productId=44.html so if it’s the same it looks like 235:1.

 

[MediumRare]

Hey @amirm , just sold my D50 (original version). Could not keep it after seeing those gross plots of ESS hump . Just could not make peace with it, even if I knew I am not going to be able to sense the difference audibly. Now, I am in real dilemma, whether to buy the D50S or DX7 Pro or just go with D70. I have Massdrop THX 789 as amp, so that is taken care of.

Lol, I bought the D50s and was waiting for the Monolith 887 when the DX7 Pro came out. So I cancelled the D50s and ordered the DX7 Pro. But since you already have an amp, the only question is how impatient are you? I suspect the D50s performs beyond the range of audibility so anything coming down the line will be better on paper only. Counter-arguments r welcome!

 

[confucius_zero]

Any ideas for rca out numbers? If I use this with the jds atom?

 

[veeceem]

Any ideas for rca out numbers? If I use this with the jds atom?

1 pair rca outs. According to measurement, jds atom is not really needed as headamp, I think

 

[confucius_zero]

1 pair rca outs. According to measurement, jds atom is not really needed as headamp, I think

Looking to output rca in the Atom. But the measurements are xlr, so I'm curious of the rca.