Topping D30 DAC Measurement and Review

[danielkt]

that’s rather strange. Switch levers shouldn’t carry voltage. Have you checked voltage of other grounding points, such as RCA connector exterior, side leg of power socket?

I test again using multimeter

rca connector (outside) = +- 150mv (stable)
back side case or near power socket = +- 150 mv (stable)

front side & switch lever : 120 mv

Forgot to mention, shocking feel doesn't alwalys come, but on few occasion when touch the switch to power off or to change input.

 

[danielkt]

top, left & right mid case : near 0v

In user manual, it is said in some very special case. Cause by electromagnetic interference component in AC adapter, I don't understand this..
Anyone understand / know the limit of security standard / safety for electronic device ?

 

[Neutron]

I test again using multimeter

rca connector (outside) = +- 150mv (stable)
back side case or near power socket = +- 150 mv (stable)

front side & switch lever : 120 mv

Forgot to mention, shocking feel doesn't alwalys come, but on few occasion when touch the switch to power off or to change input.

This is definitely not right condition. RCA socket should have 0V on the exterior. Have you checked other devices that connected to this amp? RCA of your amp and coxial of your TV?

In your case you will have a small but constant current flowing into the ground if your devices are grounded.

The manual's description is foreign to me. But it has nothing to do with your current situation.

 

[danielkt]

This is definitely not right condition. RCA socket should have 0V on the exterior. Have you checked other devices that connected to this amp? RCA of your amp and coxial of your TV?

In your case you will have a small but constant current flowing into the ground if your devices are grounded.

The manual's description is foreign to me. But it has nothing to do with your current situation.

RCA exterior of amp & coax is 0v. My amp has 3 line power cord / grounded.
So I assume it must comes from topping.

This is out of context, but interestingly I also have old technics tuner that ungrounded (only has 2 line power cord) and measure the exterior rca and got +100mv.
So could I assume this normal if the device is ungrounded / only has 2 line power cord

 

[Neutron]

RCA exterior of amp & coax is 0v. My amp has 3 line power cord / grounded.
So I assume it must comes from topping.

This is out of context, but interestingly I also have old technics tuner that ungrounded (only has 2 line power cord) and measure the exterior rca and got +100mv.
So could I assume this normal if the device is ungrounded / only has 2 line power cord

That could be. Neutral wire sometimes can carry up to a few volts. It depends on your local power grid. In that case, when you hooked up the amp and have it grounded through other devices, you should be fine.

I have been using grounded exterior PSUs for most of my stuff these days.

 

[nerone]

Hi, can anyone read the value of L5, L7, R7, R34 on the D30 board?
Thanks

 

[tvrgeek]

You are not going to feel millivolts. If you get a tingle, it is probably in the tens.

That could be. Neutral wire sometimes can carry up to a few volts. It depends on your local power grid. In that case, when you hooked up the amp and have it grounded through other devices, you should be fine.

I have been using grounded exterior PSUs for most of my stuff these days.

Neutral carrying volts is a defect in your house wiring as neutral and earth are bonded in your panel unless you have a very heavy load on the line. Even then, "volts" suggest a problem. Nothing to do with the grid. Transients are another matter.

 

[Saidera]

Is it possible for end users to program the CS4398 chip via XMOS to enable direct DSD?
https://www.diyaudio.com/forums/digital-line-level/252266-cs4398-dsd-format.html

I understand that one would use xTIMEcomposer and some other boards? Is the XMOS on a DAC recognised by a computer? Are other boards necessary? I've been through all DSD, CS4398, and DAC implementation threads on https://www.xcore.com/

Do you program XMOS before it's soldered onto the PCB or after? If it's after, then I suppose firmware upgrades and user customisation is possible (like with Realtek codecs using their confidential tools).

 

[Transmaniacon]

How does this DAC hold up compared to today’s offerings? I’ve been using mine for a few years now to handle optical input from an Apple Airport Express, and plan to switch over to USB input from an older iPhone to play lossless audio. It would be nice to have something with an internal power supply and a digital screen to show the playback quality, but if my D30 is still getting the job done I can wait.

 

[Vosya]

It would be nice to have something with an internal power supply and a digital screen to show the playback quality

I always thought that the main factor when choosing a DAC is the sound, and not the display of something on the screen.
After a direct comparison on my setup sound of D30 (even after tweaks, with his shabby CS4398) with D50 - D30 was immediately sent to the closet. And this would happen even if the D30 was completely covered with information screens, and the D50, in contrast, would not have anything, even a power-on indicator.

 

[Julf]

I always thought that the main factor when choosing a DAC is the sound, and not the display of something on the screen.
After a direct comparison on my setup sound of D30 (even after tweaks, with his shabby CS4398) with D50 - D30 was immediately sent to the closet. And this would happen even if the D30 was completely covered with information screens, and the D50, in contrast, would not have anything, even a power-on indicator.

Direct comparison by sequential, sighted listening? How did you match levels?

 

[Transmaniacon]

I always thought that the main factor when choosing a DAC is the sound, and not the display of something on the screen.
After a direct comparison on my setup sound of D30 (even after tweaks, with his shabby CS4398) with D50 - D30 was immediately sent to the closet. And this would happen even if the D30 was completely covered with information screens, and the D50, in contrast, would not have anything, even a power-on indicator.

I feel we are at the point where it’s pretty easy to produce a completely transparent DAC. So assuming that point is achieved, it’s just down to buying the features you need.

 

[Vosya]

Direct comparison by sequential, sighted listening? How did you match levels?

In the same way as I use the DACs - by ear. And that was enough. Since there are a lot of subjective acoustic features that are quite obvious even at different loudness of different sources.
I then pulled the oscilloscope out of the cabinet only to compare the impulse response of the DACs

 

[Tim Link]

I always thought that the main factor when choosing a DAC is the sound, and not the display of something on the screen.
After a direct comparison on my setup sound of D30 (even after tweaks, with his shabby CS4398) with D50 - D30 was immediately sent to the closet. And this would happen even if the D30 was completely covered with information screens, and the D50, in contrast, would not have anything, even a power-on indicator.

Sound quality of course matters, but other features are nice too. If a DAC is 2 feet tall, 6 foot wide, and 3 foot deep and weighs 500lbs I don't care what it sounds like. It's got a feature set that I can't live with. So size is an important feature. Displays are also a nice feature.

 

[Vosya]

Sound quality of course matters, but other features are nice too. If a DAC is 2 feet tall, 6 foot wide, and 3 foot deep and weighs 500lbs I don't care what it sounds like. It's got a feature set that I can't live with. So size is an important feature. Displays are also a nice feature.

These preferences are certainly important when you live in a cardboard box from a refrigerator. Personally, I buy a DAC to sound, not looks.

 

[Tim Link]

These preferences are certainly important when you live in a cardboard box from a refrigerator. Personally, I buy a DAC to sound, not looks.

You must have a big house! Still, I don't want a 500lb DAC no matter how much space I have. There's no reason for it.

 

[Transmaniacon]

These preferences are certainly important when you live in a cardboard box from a refrigerator. Personally, I buy a DAC to sound, not looks.

I think the point is, we’ve reach the plateau where performance exceeds human hearing. The only thing left to do is buy the features you need.

 

[Vosya]

I think the point is, we’ve reach the plateau where performance exceeds human hearing. The only thing left to do is buy the features you need.

Unfortunately, this is not so. Despite all the enchanting-looking specifications of modern cheap DACs, it is not always pleasant to hear their sound. I would even say - rarely pleasant.
However, I am getting stronger in the opinion that rather the main part of the unpleasant sound comes from the operating system, and not the DAC itself. As it seems to me, in relation to Windows, at least, this is the problem of short processor quantization and excessively small size of continuously allocated / freed memory sections.

 

[Transmaniacon]

Unfortunately, this is not so. Despite all the enchanting-looking specifications of modern cheap DACs, it is not always pleasant to hear their sound. I would even say - rarely pleasant.
However, I am getting stronger in the opinion that rather the main part of the unpleasant sound comes from the operating system, and not the DAC itself. As it seems to me, in relation to Windows, at least, this is the problem of short processor quantization and excessively small size of continuously allocated / freed memory sections.

I’m not sure what any of this means, but there are measurements that show well designed DACs are operating beyond the limits of human hearing. If you are talking about a poorly designed DAC and a good one, then yes that’s possible to detect a difference. However, as I’ve said, assuming a DAC measures well and is fundamentally inaudible, then you are just buying features. A DAC only needs to translate a digital signal into an analog one for amplication, there is an objective goal.

 

[Julf]

In the same way as I use the DACs - by ear. And that was enough. Since there are a lot of subjective acoustic features that are quite obvious even at different loudness of different sources.
I then pulled the oscilloscope out of the cabinet only to compare the impulse response of the DACs

The differences might feel absolutely obvious as long as you do sighted listening and only match levels by ear. They might go away in a proper, level-matched double blind comparison.