Topping D900 DAC Review

[antcollinet]

Troll much ? Member since 2022 ?

I'm fascinated by the sleepers.

 

[DrCWO]

which is over 30 years old and based on the TDA1305.

Nice.
The TDA 1305 it is a Delta Sigma DAC with 5-Bit DAC and noise shaping. THD ist -90dB at 0dB and no more SOTA
But if you like it why not. Haven't seen a 1k spectrum so no idea how the harmonics behave.

 

[Blockader]

Nice.
The TDA 1305 it is a Delta Sigma DAC with 5-Bit DAC and noise shaping. THD ist -90dB at 0dB and no more SOTA
But if you like it why not. Haven't seen a 1k spectrum so no idea how the harmonics behave.
View attachment 523400

-90 db is inaudible at normal listening levels, so if the sound image is blurry, I'd look at the reconstruction filter response rather than the noise floor or distortion figures, though the TDA1305 would need a very slow filter for that to show up.

 

[DrCWO]

so if the sound image is blurry

No one said it sounds blurry??

 

[Blockader]

No one said it sounds blurry??

''Recently did between an RME ADI-2/4 Pro and a DIY R2R NOS Dac based on TDA1541. Perfectly level matched the TDA delivered a somehow blurred response. No more depth and with and treble unpleasant. But the DIY guy claimed it is better. Probably because he loves this sound.''

Whatever you meant here. I am not good at understanding what subjective definitions really mean. Basically the audible difference, if there really is a difference, was due to the NOS, not the dac chip itself.

 

[DrCWO]

Whatever you meant here. I am not good at understanding what subjective definitions really mean.

I talked about "blurred" in the context of TDA1541. You talked about TDA1305

 

[tamtam]

Seriously, is there any audible difference between this and the $300 one?

 

[VientoB]

Seriously, is there any audible difference between this and the $300 one?

No

 

[antcollinet]

Seriously, is there any audible difference between this and the $300 one?

Of course not. Features, look and feel etc, is what buyers are (should be) paying for, if they find the value there.

(some of course will be believing the sound quality is better too - "it must be if it costs 5x the price")

 

[Panelhead]

The conversation includes multiple dac and chips. Confusing.
But the plot of the TDA1305 is horrible. Almost 1% ThD+N across the board at -60dB signal level. Imagine it is worse at lower levels.
Lower level is where I evaluate sonic performance. Not at 0dB. Usually the room, loudspeaker, and others totally mask the dac’s contribution when signal level peaks.
Most recordings I listen to have enough dynamic range that the lower levels are almost inaudible if gain is adjusted to handle frequent 0dB digital inputs.

 

[nanook]

I haven't been able to get along with any of these TDA1541-based DACs so far. I always found the sound somewhat diffuse, and acoustic instruments never sounded truly authentic.

I still have an old Philips CD304MKII at home - it's even fitted with a silver crown selection of the TDA1541 with the corresponding digital filter.
Yes I was infected by the virus back then ...

In case the CD304MKII is willing to open its drawer, I will measure a mulitone spectrum. I'm curious if it looks like "rather not audible".

 

[dhungana]

Do both of the XLR outs (pre and line out) send a signal simultaneously? Can I send one XLR to Amp and another to Subwoofer?

 

[antcollinet]

Do both of the XLR outs (pre and line out) send a signal simultaneously? Can I send one XLR to Amp and another to Subwoofer?

Yes, but the line out doesn't get volume controlled. So you would need to set volume to full and control volume somewhere else.

If you need volume control in the DAC then you can just use a passive splitter cable from the pre-outs.

 

[Vortex]

Time for Topping to create a decent 16ch DAC for all the multichannel- and home theater enthusiasts, for the latter - optionally - with a full array of DTS/Dolby licensed decoders (e.g. firmware update we can buy on the site as an extra) + a HDMI-IN.

Thanks. )

 

[taner]

External 10 MHz clock inputs are only necessary for synchronization in studio settings, but I don't see their use in a device like this.
The clock technology used in this DAC is slightly higher quality than conventional TCXO clocks, so using a different one would actually be a downgrade.

Linear power supplies are also long outdated. Good switching power supplies with tailored filters are cheaper, lighter, and deliver a lower noise level than more expensive, complex linear power supplies.

While I'm also a fan of Gustard devices, I wish they would use fewer components/technologies favored by the audiophile community and instead focus on the best option for each specific application.

You seem talking about the things that you just heard around rather having experience on the first hand. How on earth a CPLD based clock can be higher quality than TCXO? Do you even know what you are talking about? TCXO clocks are very expensive TELCO standard industrial devices. Probably costs much more than the whole conversion circuitry in D900.

Linear PSU outdated for what? This argument must be joke. Switch mode PSU's only advanteages are their efficiency, size and they are CHEAP. Nowhere in the same league with the linear PSUs for quality. Check your facts.

 

[misterdog]

Nowhere in the same league with the linear PSUs for quality. Check your facts.

I suspect your 'facts' regarding SMPS are 20 years out of date.

You can chisel down the noise from LPSU's by using superregulators, but the noise from the B100 amp in low gain using it's SMPS is less than 0.3 of a microvolt...
The Audio Precision test gear that Amir uses has more self noise than that.

It uses a SMPS..

 

[nanook]

"External 10 MHz clock inputs are only necessary for synchronization in studio settings, but I don't see their use in a device like this."
I fully agree with @Roland68. These reference clocks are useful to eliminate any drift between otherwise individually clocked devices.

Using a good xtal oscillator for the internal master clock (there are really excellent modules around) or a logic based circuit (when it's about syncing to a SPDIF or Toslink source) is just "state of the art".

Just have a look at the jitter spectrum of a decently clocked DAC - both asynchronous USB as well as SPDIF or Toslink.
And I bet you wouldn't notice an audible difference between a decently and a perfectly clean jitter spectrum.

SMPS have gotten a lot better - their leakage current often fulfills medical specs. And leakage current is the only concern that I have.
Ripple is negligible when using half decent filtering due to the higher frequency.
The only drawback is endurance - most SMPS do not survive more than a decade or two when operated 24/7. I do switch off my gear when it's not in use, so no concern either.

 

[nanook]

Nowhere in the same league with the linear PSUs for quality.

I want to add another aspect.

When using a transformer based power supply where there frequently is quite some wiring between the transformer and the reservoir caps (the location of the rectifier is 2nd) you have to make sure the loop between current and return current is small such that there's only negligible magnetic far-field.
Not paying attention to this will almost certainly result in "hum" - many commercial amplifiers do have some amount of audible hum...

For SMPS that's more straight forward - in case the wiring is not appropriate you will not pass EMI certification anyways .

Admitted:
When I see a torodial transformer with electrostatic shield foil or winding (even better a C-core transformer), Schottky diodes, large reservoir caps and a wiring that prevents the magnetic fields to couple into the rest of the circuit, I can't help but this looks nicer than a SMPS

 

[Roland68]

You seem talking about the things that you just heard around rather having experience on the first hand. How on earth a CPLD based clock can be higher quality than TCXO? Do you even know what you are talking about? TCXO clocks are very expensive TELCO standard industrial devices. Probably costs much more than the whole conversion circuitry in D900.

Linear PSU outdated for what? This argument must be joke. Switch mode PSU's only advanteages are their efficiency, size and they are CHEAP. Nowhere in the same league with the linear PSUs for quality. Check your facts.

Your information seems a bit outdated, at least 1-2 decades.
I work and develop primarily in industry, where we use clock generators with ppb accuracy, not ppm. None of these devices use TCXOs. However, I built my own 10 MHz OCXO clock with square wave output 10 years ago, which is still more accurate than any TCXO.

TCXOs are simply an inexpensive way to achieve a relatively temperature-independent and accurate clock signal. With an accuracy of 1-1.5 ppm, they cost around €3 each, and at 0.5 ppm, €10-18 each.
But it's been possible to do much better for a long time.

Topping managed to achieve such low jitter with their D900, despite the converter technology, as other manufacturers with ESS and AKM flagship DACs and expensive OCXOs, which are significantly better and more expensive than TXCOs.
So where does the mistake lie here?

I, too, once thought that switching power supplies were utter rubbish and linear power supplies with transformers the holy grail, but that was a decade or two ago.
Today, I wouldn't dream of using a transformer in an audio device, whether a DAC or an amplifier.

Incidentally, my information comes exclusively from practical experience. For over 25 years, we've been running a project where we evaluate precisely these kinds of differences using very precise, completely blinded listening tests and then compare them with measurements. We've equipped two identical devices (DACs, amplifiers, preamplifiers) with linear and switching power supplies for comparison on several occasions. It was always particularly amusing when audiophile guests were present, who would subsequently offer the most absurd excuses for why they preferred the device with the switching power supply.

 

[misterdog]

Today, I wouldn't dream of using a transformer in an audio device, whether a DAC or an amplifier.

That's another point.
SMPS being so small and light can be used outside of the device, this prevents EMI or RFI pollution inside the device.
It also means that if the SMPS fails it can be replaced easily and cheaply.

Though some will complain that it 'looks ugly' with a seperate power brick.