Topping DX7 DAC & Headphone Amplifier Review and Measurements

[amirm]

Yes.

 

[stunta]

I like how they say "to connect better DAC". Very modest.

 

[SpeedyRodent]

I think it was $379 or something like that.

BTW, I have both the DX7s and D50 in house. THe D50 has had no announcements other than a picture on their site.

Any chance you can tell us if the D50 have XLR outputs?

 

[amirm]

It does not. It is small brick and no room for XLR connectors. It has the same connectivity as D30.

 

[sonci99]

It is a pure DAC without headphone out, volume control, etc. It is much smaller. Topping told me it is NOT a replacement for D30. So not sure what its positioning is. It looks very solid and nice though.

I have not had a chance to power it up.

I see a volume control on the pic, or am I wrong?

 

[amirm]

I see a volume control on the pic, or am I wrong?

That was my mistake . I didn't see a rotary knob at first and assumed it didn't have one. But then looked again and saw the up/down arrows and display.

 

[sonci99]

I never thought these chinese Dacs could measure this good, especially on Jitter..
What about that "proprietary antijitter" circuit that most big names Dacs mention in the specs, is that snake oil?

 

[Candlesticks]

I never thought these chinese Dacs could measure this good, especially on Jitter..
What about that "proprietary antijitter" circuit that most big names Dacs mention in the specs, is that snake oil?

This costs $60 and is tiny.

 

[amirm]

In many cases they are talking about a low-jitter clock source NOT what comes out of the DAC. The output of the DAC can get polluted by other means and create jitter of its own.

Also the ultra-low jitter clock sources reduce jitter at ultra low frequencies which are simply not an audible concern to effects of masking.

 

[sonci99]

In many cases they are talking about a low-jitter clock source NOT what comes out of the DAC. The output of the DAC can get polluted by other means and create jitter of its own.

Also the ultra-low jitter clock sources reduce jitter at ultra low frequencies which are simply not an audible concern to effects of masking.

so, basically if I use a cheap transport with high jitter, like spidf out of a network player, these dacs would measure worse than in above tests?

 

[amirm]

It is not clear that a cheap S/PDIF interface is actually worse than what I measure. I can simulate jitter over S/PDIF and see how these DACs do and report back.

 

[Commissariat]

It does not. It is small brick and no room for XLR connectors. It has the same connectivity as D30.

Hey, Amirm, this is my first post in the forums. I'd just like to ask: does the Topping D50 have balanced outputs?

 

[amirm]

Hey, Amirm, this is my first post in the forums. I'd just like to ask: does the Topping D50 have balanced outputs?

Welcome to the forum. And no, it does not. The D50 is very thin, barely thicker than the RCA jacks so no room for balanced even if they wanted to put them in.

 

[Commissariat]

Welcome to the forum. And no, it does not. The D50 is very thin, barely thicker than the RCA jacks so no room for balanced even if they wanted to put them in.

Couldn't they use a 3.5mm TRRS balanced line out to save space?

Also, I'm asking because from what I could tell from Topping's specifications, the D50 seems to have a very similar circuitry to the DX7s (which is a balanced DAC, right?) so I thought it'd be a shame if it had no balanced outputs.

Edit: Added the image I found with the D50's specifications.

 

[amirm]

Thanks for the spec. Didn't know that was up. The back of the unit is full already and this is a very small box. They made a design decision to make it this way with the DX7s being the bigger brother with balanced audio out, balanced digital in, etc.

 

[Commissariat]

Thanks for the spec. Didn't know that was up.

You're welcome! I got it from the "drivers and manual" file for the DX7s. I guess the specs were not intentionally released.

The back of the unit is full already and this is a very small box. They made a design decision to make it this way with the DX7s being the bigger brother with balanced audio out, balanced digital in, etc.

That's a shame. The DX7s' output impedance is too high for my use case, so I was hoping to pair its DAC with something better. I wish I didn't have to pay the full price to have the balanced audio out feature.

 

[amirm]

You know, depending on the headphone you have, it may be possible to reduce the output impedance of DX7/DX7s. It is just a series resistor before the headphone jack. It is there to guard against too much capacitance causing oscillation. I can try to mod mine and see what happens.

 

[RayDunzl]

I can try to mod mine and see what happens.

Is it at all necessary for protection against a shorted output?

 

[amirm]

Is it at all necessary for protection against a shorted output?

No, the datasheet warns that the amp will oscillate potentially in megahertz region, degrading audible response. It is also useful for output protection but DX-7 may have a separate means for that.

 

[SpeedyRodent]

You know, depending on the headphone you have, it may be possible to reduce the output impedance of DX7/DX7s. It is just a series resistor before the headphone jack. It is there to guard against too much capacitance causing oscillation. I can try to mod mine and see what happens.

It will be interesting to see if a 2 ohm or 5 ohm resistor is enough to keep the TPA 6120 stable.

I've heard of DIY'ers using ferrites while keeping to 10 ohm series resister in place. This essentially lowers the output impedance to near zero. IIRC, I was told the measured trade off is slight increased thd+n. I first heard of this quite a few years ago, maybe 7+ years so my memory is testing me. I exchanged messages with a diy'er that successfully completed this mod on a TPA 6120 buffered headphone amplifier and measured on a dscope. I'll see if I can dig up information about how this was done.