Powering a USB-powered DAC

[Taz777]

If you have a DAC that requires USB power (i.e. 5V, 1A) then there are several options:

 

1. A spare USB port on your computer;

 

2. A phone charger;

 

3. A 'power bank' battery pack that is usually used to charge mobile phones;

 

4. A linear power supply;

 

5. A 'specialist' switched power supply like iFi iPower 5V.

 

There may be other options too. However, from the above list, which would you choose and why? The end result is to improve the analogue audio of the DAC.

[JanRSmit]

This is exactly what i want to know also. Would like to see also included measurements that match the heard/observed findings.

[matthias]

The ultimate best would be either directly powered by an Ultracapacitor PS without any additional LDOs or by the dual regulated version of the Paul Hynes SR7 PS.

 

Matt

[Taz777]

On 12/28/2018 at 9:04 AM, JanRSmit said:

This is exactly what i want to know also. Would like to see also included measurements that match the heard/observed findings.

 

I've been using an iPad charger (5V 2.4A) for a while with my second Topping D50. The sound has been good. Last night I swapped out that iPad charger for an iPhone charger (5V 1A). The sound wasn't as good as before to my ears, quality wise. It appeared to be a little lighter and 'detached' somewhat, compared to what I was hearing before.

 

This morning I used my Anker PowerCore 20100 mAh power bank. The sound is a little better now - better than the iPhone charger was. All of this is purely based on how the music sounds to my ears when playing a couple of nicely recorded familiar tracks. I'd say it's an even match between the iPad charger and the power bank.

 

The really big downside of the power bank is having to recharge it. It takes 8-10 hours to recharge fully. The Bluesound Node 2i streamer doesn't go to sleep properly when there's no audio being played, so its digital coax output is 'always on' - causing the Topping D50 not to auto-shut off either, so that in turn is drawing current all the time, draining the power bank slowly. I will stick with the iPad charger until I get my linear power supply in a few weeks time. Also, just out of interest, my ears cannot tell a difference between the iFi iPower power supply and the iPad charger when either is used with the Topping D50.

 

Sorry, no measurements available, but only how good the music sounds to my ears. All purely subjective, of course.

 

As things stand, for powering my Topping D50 DAC, the iPad charger is currently the best power supply that I have. I'm hoping that the linear power supply that I've ordered (an item described as 'LKS Linear power supply DC 5V USB 5V for DAC with 25VA Talema transformer PSU') will improve upon the iPad charger.

[audiobomber]

@Taz777 How did your new PS work out? How is the SQ compared to the power bank? I'm in the same boat. My RavPower 26,800 mAh power bank sounds better than my iPower 5V and Chromecast Audio SMPS, but I keep forgetting to charge it.

[Taz777]

19 minutes ago, audiobomber said:

@Taz777 How did your new PS work out? How is the SQ compared to the power bank? I'm in the same boat. My RavPower 26,800 mAh power bank sounds better than my iPower 5V and Chromecast Audio SMPS, but I keep forgetting to charge it.

 

I ditched the powerbank as the hassle of charging it every day was annoying. One big reason was that my Bluesound Node 2i streamer keeps a live signal on the digital coax out, which goes into my Topping D50. This means that my Topping D50 ia always on and never goes into sleep mode, even when the Node 2i was idle and not playing any music for a long time, so it drained the powerbank very quickly. I reported this issue to Bluesound who didn't seem to care.

 

The powerbank did sound a little better than an iPad charger and an iFi iPower.

 

Anyway, I replaced the powerbank with an LPS (LKS Audio LPS from China, which arrived within two weeks to the UK) and I am very pleasantly surprised. The sound is exquisite from the D50 now - a distinct improvement compared to the powerbank. It's so good that I've ordered another LPS for my second D50 that I'll be putting back into my desktop HiFi system. Sadly the LPS that I ordered for my first D50 (the one I use in my headphones system) is no longer stocked by the seller, so I have a different Chinese-made LPS on order, but it still has a Talema 25VA transformer in it.

 

I highly recommend an LPS with the Topping D50 (and Topping DX3 Pro). As always, YMMV. The cost of an LPS is two-thirds of the DAC, so it's a bit of an investment but can be re-used for future DACs.

 

If you're interested in a 5V LPS for your DAC (assuming it's 5V USB powered DAC) then you may be interested to know that I've ordered item number 132912100672 from eBay UK. That was the closest spec that I could find to my original LKS Audio LPS. I'm happy to report back on whether not it improves the SQ once I receive it.

 

The blurb on the advert says this:

 

Quote

This psu is customized for TOPPING D50 DAC
 
Output voltage:   DC 5V / 3.5A

this price is for upgraded to hifi quality brand 25VA Talema transformer

>>it is Ultra-Low Noise linear power supply
>>high-quality components :you can see the photo

Precision Reference + high speed op amp + MOS output transistor, ultra-low-noise voltage regulator circuit
Thick textured aluminum enclosure with heatsink
Vishay high current rectifier diode
Philips + Panasonic FC electrolytic capacitance
Multiple sets of precision high current filter inductor

size:  150 x 140 x 40 mm
weight 1.3KG

 

I also have a different 15V LPS (LHY Audio) on my Topping DX3 Pro and it improved the sound compared to the cheap and nasty 'phone charger' style of adapter that came with that DAC.

[Panelhead]

I power the USB 3.0 hub in my system with the 5v iPowersupply. It handles the spinning external drives well.

  This is my recommendation for a USB powered dac.