Topping E30 DAC Review

[kkeretic]

What's a good USB charger for power input that will superseede powering it from the USB-B cable?
I see Apple Chargers are shown to be of good quality in test:
https://lygte-info.dk/review/USBpower Apple USB power adapter UK.html

Any decent $10 price range 5V 1A+ cell phone charger should be ok. I am using this for both of my D50s's, also for phone charging for years, works perfectly. More than twice the power of Apple's charger for half the price.

 

[MrOtto]

I plugged my E30 into my laptop USB3.0 A port, but the DAC wouldn't power on. Aren't these also supposed to run on only power via the USB-B port?

 

[Mindcool]

I plugged my E30 into my laptop USB3.0 A port, but the DAC wouldn't power on. Aren't these also supposed to run on only power via the USB-B port?

No, you need to supply power to the separate DC jack.

 

[MrOtto]

No, you need to supply power to the separate DC jack.

Ok, thanks. I have misunderstood. Good it isn't broken. It works when plugged into a separate USB-charger.

 

[tox1c90]

Has anyone out there already seen or done an experiment like, e.g., artificially introducing noise in the power supply rail of a USB DAC and just measure how the DAC output is affected depending on the magnitude of noise?
Would serve as a good argument in discussions against people claiming that their super-duper 500€ power supply leads to a 'cleaner' sound although the unit filters its power so that technically the 5€ USB charger should work just as good. Would also be interesting to see how ****** a power supply actually can be before it introduces distortions at a noticeable level.

 

[Jestercow]

Add me to the failure list, opened my E30/L30 stack this weekend (happy birthday me!) and plugged it in for the first time at work this morning. Got an E-d message on the E30 as soon as I plugged it in and came here to find that it's DOA. :'(

 

[TheTalbotHound]

Hi everyone. Has anyone measured the preamp section of the E30 separately to its DAC section or is that not possible?

 

[PyramidElectric]

On another note, Topping informed me that with some powered speakers from Genelec mostly (and Dynaudio mine) the E30 can't turn them on from a standby mode, without resetting the E30. I decided to upgrade to DX7 Pro and go balanced.

For anyone interested/concerned about this, my E30 seems to have no problem waking both my Genelec 8020D from 'sleep' mode.

 

[BDWoody]

Hi everyone. Has anyone measured the preamp section of the E30 separately to its DAC section or is that not possible?

Not entirely sure what that means...

The combined output is the only thing that will ever get to speakers or headphones (after amplification), and that is what's measured.

The recent increase in 'but what about the output stage' questions make me wonder if that's the most recent attempt to figure out where the hidden 'sound signature' must be.

It's all one unified box. It all gets measured at the analog outs.

 

[Doodski]

Hi everyone. Has anyone measured the preamp section of the E30 separately to its DAC section or is that not possible?

That would req disassembly of the unit, tedious effort to cut into the circuitry and to match the power transfer from the DAC section to the analogue input/output section. It would be ineffective. Yes, it could be done but it's redundant to do it. Lots of things are possible but not worthy of being done.

 

[PyramidElectric]

It’s my understanding that volume attenuation (I assume this is what’s meant by ‘pre amp section’) is done within the DAC chip (at 32bit precision), unless AK somehow messed this up, it’s likely to be essentially perfect.

 

[bravomail]

Has anyone out there already seen or done an experiment like, e.g., artificially introducing noise in the power supply rail of a USB DAC and just measure how the DAC output is affected depending on the magnitude of noise?
Would serve as a good argument in discussions against people claiming that their super-duper 500€ power supply leads to a 'cleaner' sound although the unit filters its power so that technically the 5€ USB charger should work just as good. Would also be interesting to see how ****** a power supply actually can be before it introduces distortions at a noticeable level.

Amir did. Read OP.

 

[TheTalbotHound]

Not entirely sure what that means...

The combined output is the only thing that will ever get to speakers or headphones (after amplification), and that is what's measured.

The recent increase in 'but what about the output stage' questions make me wonder if that's the most recent attempt to figure out where the hidden 'sound signature' must be.

It's all one unified box. It all gets measured at the analog outs.

oh so preamp mode doesnt bypass the analogue stage, just sets it to 0.

 

[BDWoody]

oh so preamp mode doesnt bypass the analogue stage, just sets it to 0.

Correct.

 

[bogi]

It’s my understanding that volume attenuation (I assume this is what’s meant by ‘pre amp section’) is done within the DAC chip (at 32bit precision), unless AK somehow messed this up, it’s likely to be essentially perfect.

... and yet better if you would do that in a software player. Why?
- Software players, including free foobar2000, perform internal volume calculations in 64bit floating point and only the result of calculation is rounded to fit the DAC interface (32 or 24 bit for current DACs). So the calculations are done in higher precision on PC. Also the algorithm used on PC (including some filtering and dithering of the rounded result) has potential to be of higher quality because it can use much more computational resources.
- There are many recordings which are mastered up to 0dB. Playing them leads to intersample overs and thus clipping with most of delta-sigma DACs because of their oversampling nature. Oversampling (interpolation) raises dynamic range and SNR from its principle and fixed point PCM data representation cannot exceed 0dB. But if you lower volume to about -3dB in your software player, no clipping will happen with any recording. DAC volume controls don't help with that, because as you can see on schematics of DAC chips the volume control is typically placed between interpolator and delta-sigma modulator.

 

[samsa]

... and yet better if you would do that in a software player. Why?
- Software players, including free foobar2000, perform internal volume calculations in 64bit floating point and only the result of calculation is rounded to fit the DAC interface (32 or 24 bit for current DACs). So the calculations are done in higher precision on PC. Also the algorithm used on PC (including some filtering and dithering of the rounded result) has potential to be of higher quality because it can use much more computational resources.

I don't think the difference between 32bit integer computations and 64 bit float computations is a big concern. Either way, the rounding errors are way below the threshold of audibility.

- There are many recordings which are mastered up to 0dB. Playing them leads to intersample overs and thus clipping with most of delta-sigma DACs because of their oversampling nature. Oversampling (interpolation) raises dynamic range and SNR from its principle and fixed point PCM data representation cannot exceed 0dB. But if you lower volume to about -3dB in your software player, no clipping will happen with any recording. DAC volume controls don't help with that, because as you can see on schematics of DAC chips the volume control is typically placed between interpolator and delta-sigma modulator.

Applying a headroom adjustment of (say) -3dB before sending the signal to the DAC will, indeed, save many a badly-recorded track from intersample overs.

After that, it doesn't matter where the fine volume adjustment takes place. In many cases it will be far more convenient to do that with the remote control supplied with the E30 than by accessing the software player on a PC that might not even be in the same room.

But, again, what's most convenient depends on your setup and there isn't a general statement that can be made.

 

[PyramidElectric]

@bogi yep, you're totally correct, but like @samsa says, there's other convienience factors at stake... Using the E30 as the pre amp with active speakers works well as it reliably remembers the 'last volume' setting, something which all my software (iTunes/Audirvana/BitPerfect) seems to struggle with.

 

[Stephen Dawson]

I don't think the difference between 32bit integer computations and 64 bit float computations is a big concern. Either way, the rounding errors are way below the threshold of audibility.

Applying a headroom adjustment of (say) -3dB before sending the signal to the DAC will, indeed, save many a badly-recorded track from intersample overs.

...

Curious. Do intersample "overs" matter? Assuming that a line-level DAC like this one can deliver the necessary volts, and the input to which it is connected can cope?

 

[Rock Rabbit]

Curious. Do intersample "overs" matter? Assuming that a line-level DAC like this one can deliver the necessary volts, and the input to which it is connected can cope?

An "over" means interpolated signal over 0 dBFS some DACs have headroom for this, many DACs have worst distortion (saturation) even near 0 dB so better is to stay some dBs below digital 0

 

[Stephen Dawson]

Thanks Rock. So, really, it depends on the particular DAC. I've got one of these coming, so I'll check it out. Now, to think of a way to reliably get a >0dBFs signal going!