Topping D900 - teardown

[whydan]

Great photos!
Unfortunately, I expected a lot more for €1800.
Why another Mickey Mouse power supply?
Why these sound horrible mute chips on the output instead of decent relays? It's not worth the money.

haha Mickey Mouse power supply.
I don't like swithing power supply neither but there are two reasons after doing my homework.
1. Isolated switching power supply may reduce 60hz (or 50Hz) power from AC source.
Rest higher frequency noise required more C-L-C filter and LDO to reduce.
Topping provide measurement report which shows they did a good job on it, so I have no complient on it.
2. DSM module required low temperature drift resistor, linear regulators may increase temp in chassis.

For mute chip, I didn't have the full picture, suspect that analog switch may have lower resume time to reduce pop noise.

 

[BeeKay]

Internally, the D90 is not handling the inputs that same.

Means? We are talking same sampling rate, right?

 

[whydan]

Thanks for the insights! Here I had up to 25°C in-room-temperature in the last days when it was upwards of 30°C outside, and I am thinking about an AC unit for my apartment, but 33°C? Ouch, my body would shut-down under these circumstances.

I drop D900 for burn-in the whole day then go to work, just record that temp when I come back home.
We can't leave AC in taiwan, quite hot here in summer.

 

[BeeKay]

for burn-in the whole day

It’s a shame such service isn’t available right from the factory.

 

[Pearljam5000]

If all DACs sound the same
Then why buy an expensive one?

 

[unpluggged]

If all DACs sound the same
Then why buy an expensive one?

For advanced features, for usability, for build quality, for great support. Little of which applies to this particular product, though.

 

[RichB]

Means? We are talking same sampling rate, right?

The specs are different on different inputs. For example, I2S does not support PEQ.
This device, and others, do not perform the same on all inputs.
Not all inputs are tested on ASR.
A DACs volume control is not tested. The input signal at different levels is measured with the device at Maximum volume.

Certainty is nice, but the testing at ASR is insufficient to make claims that in use, all DACs sound the same.
There are too many variables and untested modes.

ASR provides a of tests, consistently applied, that are useful to verify basic design hygiene.

- Rich

 

[Ground Noise Industries]

Thank-you for the thorough teardown. Very professional.

 

[audiofun]

The top LQF48 IC is for PEQ but didn't know which IC is. The SRC bridge looks like CT7302 which can be used for DSD converter and SPDIF receiver.

I wrote about the 48pin chip topping uses here: https://www.audiosciencereview.com/...-e30-ii-dac-review.36028/page-50#post-1574750

 

[audiofun]

There are two OPA on preamp, I guess the tiny one is OPA1612 as power supply and bigger one is OPA1656 as gain stage, the whole design may come from A70pro.

From the traces I don't believe 1612 is the power supply of the 1656. The reference power is also not near by.
The shifting register board, however, do use op amp as power supply, as the zener diode is close by.

The power of resistors matrix also came from OPA1612.

Same. There's no point to power the resistor matrix using 1612. This is close to the XLR output, so definitely the output buffer.

The AC coupling caps used Nichicon MUSE BP 100uF 25V on direct output of DSM32 board.

This is very interesting... as they have potentiometer before the capacitors to cancel the DC offset already

 

[boXem]

From the traces I don't believe 1612 is the power supply of the 1656. The reference power is also not near by.

It's indeed the same composite opamp as the one used on the A70 pro.

 

[audiofun]

The clock on DSM32 board used 11.2898 MHz, but I can recognize which brand of it.

My understanding is the hardware’s native format is DSD256.

The SRC bridge looks like CT7302 which can be used for DSD converter and SPDIF receiver.

No wonder. Topping is not doing any hard work Mola Mola did (sigma-delta conversion, high order filter, upsampling, interpolation, etc).

They just use existing chip to convert everything to DSD256. The rest of the things (shift register + power supply) is relatively easy and straightforward.

 

[Dawsoo]

Do you mean this mola mola?

'Mola Mola Tambaqui DAC and Streamer Review'

Jan 8, 2020

This is a review and detailed measurements of the Mola Mola Tambaqui USB DAC and Ethernet streamer. It is on kind loan from a member which is quite special when you consider it costing US $11,500 (£8,999).

As it should be the Tambaqui weights a lot relative to its size with generous use of free-form thick metal enclosure:

You really feel like you have a high-end audio product until you touch it. The corners and edges are all extremely sharp. Not that you are going to handle it by hand but I always like to see the edges burnished at least, if not rounded.

There is a...

• amirm
• Replies: 281
• Forum: Digital To Analog (DAC) Reviews and Discussion

• 

If so, I would say that the D900 certainly looks better on the APx555. And not to talk about the price.

 

[audiofun]

Do you mean this mola mola?

If so, I would say that the D900 certainly looks better on the APx555. And not to talk about the price.

A $200 DAC using off-the-shelf chips such as D50III can beat both. Mola mola and D900 are certainly not for you.
D50III has better SNR and noise performance than D900, and same SINAD.

If you are talking about how much R&D one need to put into such device, building the mola mola is *way* more difficult than topping.
Topping entirely skipped the real hard part (math and fpga programming) and use off-the-shelf solution for that.
Their work is easy. You can even find open source hardware solutions that perform fairly well on DIY Audio.
And the solution was there way before topping started developing D9000.
By making the shift register 4 times wider, selecting better flip flop switches, using better power supply and i/v converter circuit,
reaching this performance is not a huge engineering challenge.

Also mola mola was designed in 2013. That's 12 years ago.
Many of the current techniques and better performing components were not available, but the performance was unheard of.
At that time, similar technology products (such as Chord) perform way (10db+) worse. Even DACs using off-the-shelf chips also perform way (10db+) worse.

 

[Dawsoo]

A $200 DAC using off-the-shelf chips such as D50III can beat both. Mola mola and D900 are certainly not for you.
D50III has better SNR and noise performance than D900, and same SINAD.

If you are talking about how much R&D one need to put into such device, building the mola mola is *way* more difficult than topping.
Topping entirely skipped the real hard part (math and fpga programming) and use off-the-shelf solution for that.
Their work is easy. You can even find open source hardware solutions that perform fairly well on DIY Audio.
And the solution was there way before topping started developing D9000.
By making the shift register 4 times wider, selecting better flip flop switches, using better power supply and i/v converter circuit,
reaching this performance is not a huge engineering challenge.

Also mola mola was designed in 2013. That's 12 years ago.
Many of the current techniques and better performing components were not available, but the performance was unheard of.
At that time, similar technology products (such as Chord) perform way (10db+) worse. Even DACs using off-the-shelf chips also perform way (10db+) worse.

I don't deny that it's more difficult, I'm talking about the result. Here topping showed that there's no need for such effort to achieve even better results. D50III is nonsense, I tried it as a novelty out of curiosity and sold it after a week, because it didn't suit me at all and it's certainly not better in terms of parameters than D900.

I'm not a person who claims that everything works the same, but I also don't accept overpriced stuff that doesn't bring any real improvement. It's always about the maximum extracted from the minimum and adequacy. I'm considering the D900 as one of the few that I'll buy later, when the bugs are fixed, mola mola is the best in the category of overpriced high-end creations, I wouldn't want it even for the price of topping, when I see independent measurements and I had the opportunity to hear it in a good chain. sorry.

 

[whydan]

I wrote about the 48pin chip topping uses here: https://www.audiosciencereview.com/...-e30-ii-dac-review.36028/page-50#post-1574750

I checked LC89058W datasheet and this chip may not we look for, LC89058W used for SPDIF receiver in E30 II but CT7302 already covered.
48pins DSP with EQ will have a lot of options and I don't have concern on it since Topping already provide a good measurement on jitter.

From the traces I don't believe 1612 is the power supply of the 1656. The reference power is also not near by.
The shifting register board, however, do use op amp as power supply, as the zener diode is close by.

Topping already used OPA1612 as power source on couple of DAC and headphone amp so I believe this is a solid design.

Same. There's no point to power the resistor matrix using 1612. This is close to the XLR output, so definitely the output buffer.

I'll trace it again once available

This is very interesting... as they have potentiometer before the capacitors to cancel the DC offset already

probably potentiometer used for preamp

 

[audiofun]

Topping already used OPA1612 as power source on couple of DAC and headphone amp so I believe this is a solid design.

I'm not saying using op amps is not a good design.but here it's not power source of the other opamp.

I'll trace it again once available

You don't need to. Your photo is clear enough to see it. Just look at the PCB traces on your teardown photo. the output of the op amp goes to the resistor marked 49R9 (50Ohm), then to the relay on the left, then to the XLR output. It's very clear, especially the top half of the circuit. if it's power source it should go to the right.

I checked LC89058W datasheet and this chip may not we look for, LC89058W used for SPDIF receiver in E30 II but CT7302 already covered.
48pins DSP with EQ will have a lot of options and I don't have concern on it since Topping already provide a good measurement on jitter.

Topping just copy their designs over and over. D900 is an old product (by old I mean design not release) and at that time Topping used it on all of their devices for signal routing. Topping only realized how to route spdif to xmos a few years later (after D50 III) so in recent designs they abandoned it. But they don't want to change the existing, finished, designs, especially on this premium device, as there's no need to save BOM.

BTW, the chip has two round orientation markings. Very few chip has those. So if you see the two orientation markings, it's definitely LC89058W.

Moreover, if you really have read the datasheet as you said, you will understand LC89058W is the chip they use in D900, based on your teardown photos.
Go to page 63 of the datasheet. you'll find resistors/capacitors/data lines match *exactly* to the reference design.

 

[audiofun]

My understanding is the hardware’s native format is DSD256.


No wonder. Topping is not doing any hard work Mola Mola did (sigma-delta conversion, high order filter, upsampling, interpolation, etc).

They just use existing chip to convert everything to DSD256. The rest of the things (shift register + power supply) is relatively easy and straightforward.

This is further proved by their manual. In the "DSD bypass" section, they listed acceptable format is DSD64-DSD256. So DSD256 is the machine's native format.

If you have anything else feed into the machine, it will first convert that to DSD256.

 

[ternam]

This is further proved by their manual. In the "DSD bypass" section, they listed acceptable format is DSD64-DSD256. So DSD256 is the machine's native format.

If you have anything else feed into the machine, it will first convert that to DSD256.

Which chip is used to convert All to DSD 256? LC89058W?

 

[audiofun]

Which chip is used to convert All to DSD 256? LC89058W?

mentioned above. CT7302