[spacequeen7]

Thanks, I've done that. The DAC is at 0dB and I'm using the volume control on the speakers. I've set the gain on the speakers to the lowest of three available settings. I'll try setting the gain the speakers to the middle setting and then lower the volume on the DAC.

By the way, the first upgrade in sound quality was free. I used a spare iPhone charger to power the DAC rather than using a spare USB port on the computer. Now the loudest parts of a song are not distorted.

My D50 also appears to have the latest software on it as it wasn't within the range of serial numbers on the Topping site that the current firmware update was designed for. Apparently the current firmware has lots of USB noise improvements and I'm surprised I'm not hearing any noise from the USB source.

I'm using iFi iPower but nothing beats power bank or linear PSU,I updated the firmware few weeks ago ...couldn't tell the difference

 

[Taz777]

A power bank is a much cheaper option than a linear power supply but is likely to require more maintenance.

I'm using iFi iPower but nothing beats power bank or linear PSU,I updated the firmware few weeks ago ...couldn't tell the difference

AudioScienceReview shows that iFi iPower isn't that great (according to the noise graphs). USB power from a spare USB port on a computer to the Topping D50 was only marginally worse than a lab power supply. Best of all was battery power.

I may buy a powerbank just to see whether it makes any difference.

I started off with USB power from a spare USB port on my computer. I then changed to an iPhone 5V 1A charger. I thought it was better until I realised that I had turned down the gain on my active speakers to stop the slight distortion at high input levels. I went back to a spare USB port and it sounds just fine.

 

[carlmart]

What powerbank are you thinking of?

 

[Taz777]

What powerbank are you thinking of?

I don't know yet as I haven't started the research. Any recommendations?

 

[Collusion[FIN]]

Powerbanks are not good, they have cheap and noisy step-up converters to boost up the voltage of the internal batteries. If you really want to get something better, buy a high quality wall wart.

Then again, it is also possible that D50 has an internal switcher, which in the end becomes the ultimate bottleneck.

 

[carlmart]

Yes, the D50 internal supply is a switching type, instead of linear, and I believe it might be a bottleneck.

It's the price you have to pay to use power through the USB interface, or even feeding one single supply through the power socket.

This has to be stepped up to the different voltages inside. You need DC-DC switching for that.

 

[spacequeen7]

A power bank is a much cheaper option than a linear power supply but is likely to require more maintenance.


AudioScienceReview shows that iFi iPower isn't that great (according to the noise graphs). USB power from a spare USB port on a computer to the Topping D50 was only marginally worse than a lab power supply. Best of all was battery power.

I may buy a powerbank just to see whether it makes any difference.

I started off with USB power from a spare USB port on my computer. I then changed to an iPhone 5V 1A charger. I thought it was better until I realised that I had turned down the gain on my active speakers to stop the slight distortion at high input levels. I went back to a spare USB port and it sounds just fine.

I'm aware of AudioScience test and I'm also a member,iFi iPower works just fine without nitpicking -noticeable upgrade over stock power cable ,here are two reasonably priced options
https://www.amazon.com/gp/product/B00Z9QVE4Q/ref=oh_aui_detailpage_o06_s01?ie=UTF8&psc=1
http://www.kingrex.com/products.php?c=6&s=8

BTW; charging power bank every other day can be pretty irritating

 

[carlmart]

Recharging will depend on the device consumption and the battery capacity.

But I think in this case it might not be that interesting using a powerbank instead of a linear regulated supply, with plenty of current capability.

I'm not sure what's inside the iFi iPower, but as long as it is linear and not switch type, it should be fine.

Using a very low noise supply might be overkill, because the advantages might fade away because of the connecting cable and the D50 internal regulation.

But if there is a chance, trying several supplies and listening might get good results.

 

[wwmhf]

Some Powerbanks use cheap and noisy converters, but there are good ones. In general, I like a linear power supply better.

 

[Taz777]

I have an iFi iPower 5V power supply on order so I can test the audio quality with that versus a spare USB port on my iMac.

Also, I've noticed a nice improvement in audio quality by changing my interconnect cable from the Topping D50 to my Ruark MR1 Mk2 active speakers. I previously had a budget 1m length twin-RCA to 3.5mm stereo jack from the D50 to the speakers. The sound was quite acceptable. I then purchased an AudioQuest Tower 3.5 to twin RCA cable in a shorter length (0.6m). It's a nicely constructed cable and has made a noticeable difference to the sound quality. The sound is more spacious now with a little more detail.

 

[Taz777]

So, following on from the slight improvement in audio quality by upgrading the interconnect cable between my Topping D50 and active speakers, I'm now using an iFi iPower power supply for the Topping D50 - I was previously using a spare USB port on my iMac.

Initial thoughts are that there is a slight improvement in the control of the music that's coming out of my speakers. Instruments are marginally more well-defined and there is a clearer separation between instruments. I'll need to listen for many more hours to see if using the iFi iPower power supply is a real improvement or not, but I think that it does help a tiny bit.

My next upgrade to my computer-based sound system will be the addition of a subwoofer that will be connected by the subwoofer line output of my speakers. I'm hoping this will help to produce a fuller sound as my speakers, whilst being of very high quality, are limited in the bass department due to simple physics based on their diminutive size.

 

[xLoud]

Did anyone compared D50 to iFI iDAC2 or iDSD Black Label?

 

[439598]

There is a pretty advanced but very effective mod you can make to the D50 to fix the overly smooth sound and muted dynamics.
The D50 uses some sort of step up and voltage doubler to generate +8/-8V rails for the amplifier stage from 5v input, not good, the UDA38 already allows you to use a 12V supply for amps through its power input. Luckily this cruddy supply is connected to the amplifiers through zero ohm links (google zero ohm link and check the D50 PCB for +8V and -8V and you will see it), removing these links will disconnect the internal supply and let you connect a good one (this is a very good value regulator board which im using, it needs a DC input).
Im using +12V/-12V to compare to the UDA38 but you could probably go higher since the OPA1612 has recommended supply of +/-18V, it could sound even better that way.

Both of the DACs are on equal playing field now with this mod and I cant choose between them. for mids, holographic imaging and airy sound the UDA38 is a good (suits hd600/650).
For smooth/clean sound throughout from the lows to highs, better seperation and more weighty sound go for the D50 (suits He400i/560).
Finally, the D50 does have more features and a slick design but the thing that matters most day to day is the volume control and it's slow and finicky.

 

[carlmart]

This is a very good move. I don't still have a D50, but will probably buy one shortly.

What I have seen on D50's pcb photos is that they use DC-DC to get the other voltages, which is not good. Particularly because it involves inductors that make a very noisy RF environment inside the box, even if they are shielded.

Having zero ohm resistors linking the supply to the internal opamps is a very good thing, even if that is not applied on all of them. Getting a schematic would be great, but I'm pretty sure it must be difficult.

The datasheet does not recommend +/-18v voltage, it only specifies it as the maximum one. On such cases I think you should go up to +/-17v at most, even if the usual +/- 15v would be more than fine. The question is the quality of that supply: noise, impedance, etc.

About the volume control, only a schematic might show how to improve it.

 

[439598]

This is a very good move. I don't still have a D50, but will probably buy one shortly.

What I have seen on D50's pcb photos is that they use DC-DC to get the other voltages, which is not good. Particularly because it involves inductors that make a very noisy RF environment inside the box, even if they are shielded.

Having zero ohm resistors linking the supply to the internal opamps is a very good thing, even if that is not applied on all of them. Getting a schematic would be great, but I'm pretty sure it must be difficult.

The datasheet does not recommend +/-18v voltage, it only specifies it as the maximum one. On such cases I think you should go up to +/-17v at most, even if the usual +/- 15v would be more than fine. The question is the quality of that supply: noise, impedance, etc.

About the volume control, only a schematic might show how to improve it.

the max voltage is +/-20V for OPA1612, you might be looking at the wrong datasheet. for +/-18V max op amps like LM4562 is best not to exceed 15V because performance suffers

they use +/-15V for all the examples though, best thing would be to listen and compare 18 vs 15