The iFi iUSB Power Supply - Neat Tweak & Upgrade for USB DAC

[Musicophile]

I received Bel Canto mLink and the iUSBPower together on the same day and added them one by one to my system. The iUSB had a higher impact in SQ than the Bel Canto mLink (in my system). And iUSB was half price the Bel Canto mLink. Very likely my MBP is a noisy computer transport and the iUSB clears up the sound.

 

OK, now you got me thinking. When it eventually makes it's way into Switzerland and I can try it out at home, I'll give it a try.

[wisnon]

Musicophile, are U in CH too?

 

I am in Genf and I already have an iUSB but have not used it yet. LoL

 

Wod Audio of Germany is the disturb for CH.

[Dj]

 

I am in Genf and I already have an iUSB but have not used it yet. LoL

 

 

Hmmm, You have been promoting iUSB since it came out although you haven't used yours yet? LOL

 

Or you have a second one sitting there unused?

[wisnon]

Not in my system yet...Xmas, family, travel.

 

However, I DO know how good it is and WHY it is good. Plus I have a few friends who tested it out...

 

$200 is an easy promote and a quite admirable development on the market, wouldnt you say?

 

Any company that comes up with classy performance for cheap will get my fullsome support.

 

I see you have one..what do YOU think?

[Dj]

 

Any company that comes up with classy performance for cheap will get my fullsome support.

 

 

It seems like not only they do a good job building performance equipment for cheap but also have very friendly customer support. I bought a very early version without the USB to DC cable. I contacted them and they replied same they. I got the cable for free. They are giving away the cable for free if you bought the earlier version.

 

 

I see you have one..what do YOU think?

 

I am usually very critical with hocus pocus and magic of the cable and equipment. Last night I thought I do another test again without the iUSBPower and then with. All I can say the sound becomes cleaner and clearer with it. It is probably the BEST $200 spent on any equipment. But as I mentioned earlier this works on my system because I may have an old and noisy MBP. That is why I notice the positive impact. It may not work with another person's system.

[tubesound]

I found the effect of iUSB is highly dependent on how good your USB to SPDIF converter or USB DAC is. However, I stil feel their claim that iUSB's switching power supply is cleaner than battery is kind of suspicious.

[wisnon]

DJ,

 

I agree with all you say.

 

I too bought an early one on a trip to the US and still miss some cables. I expect to get them when I order the Gemini cable...

[John H. Darkø]

I dont understand...no IFI product is battery powered....that is the point!

 

Nothing was negative in the darko review as he clearly stated that his sample ifi iDAC was faulty!

 

I gotta chime in here with a mea culpa (sort of). My iDAC isn't faulty, it just didn't come with a manual (which apparently tells users to set the headphone volume to zero for best DAC sound). Now that I've done that, the iDAC sounds terrific. The iUSBPower really does take it up a coupla clicks.

[John H. Darkø]

Squidly,

 

Only for SOME USB/Spdif converters. It was inconclusive overall for converters but overwhelmingly positive for direct USB input on Dacs.

 

At this price, for me it is worth having in the arsenal as I can power SBT and Duet with the iUSB or its 9v very low noise SMPS as well as isolate the DAC from the PC. Very versatile and priced to attract, not to horrify.

 

Absolutely wisnon - you got the gist of my review completely.

 

However, I will add that USB implementations that have their own internal power feeds (e.g. Metrum Hex) are less likely to be seduced by the iUSBPower's charms. Potential buyers should ascertain how their DAC derives its 5V before dropping their money on the counter.

[tubesound]

iUSB actually degraded the sound of my Stahl~Tek USB to SPDIF converte: less fluid. Stahl~Tek has lithium ion battery power supply and it applies ADUM isolation chip inside (on the i2s side).

[Superdad]

Absolutely wisnon - you got the gist of my review completely.

 

However, I will add that USB implementations that have their own internal power feeds (e.g. Metrum Hex) are less likely to be seduced by the iUSBPower's charms. Potential buyers should ascertain how their DAC derives its 5V before dropping their money on the counter.

 

That's really easy to do: Cut a 3mm wide strip of a business card and use it to cover up pin 1 of your USB cable's "A" end (the one that goes into the computer); Carefully plug it in and then see if your DAC still works.

 

Mine does, but that is because I specifically had a PS built into the DAC when I upgraded the USB to an async-XMOS implementation. And yes, I do now prefer to have the 5V USB power lifted at the computer (still just using the paper strip) so that it is not present on the cable length at all. A small but very clear improvement with my PCM1704 NOS DAC (at 24/192 with custom Izotope settings in A+).

[SteveS1]

iUSB actually degraded the sound of my Stahl~Tek USB to SPDIF converte: less fluid. Stahl~Tek has lithium ion battery power supply and it applies ADUM isolation chip inside (on the i2s side).

 

I'm interested in why you thought it would. Isn't the purpose of the iUSB to improve on computer bus power? I would be pretty amazed if it helped the device you highlight given it's attention to battery power and considerable cost.

 

I have an iUSB and find it a good addition to my Stello U3 replacing the Mac Mini's USB power. It lifts the performance of the already very good Stello.

[wisnon]

I found the effect of iUSB is highly dependent on how good your USB to SPDIF converter or USB DAC is. However, I stil feel their claim that iUSB's switching power supply is cleaner than battery is kind of suspicious.

 

Its more than an idle claim though, they tested with fancy equipment and posted the results, so unless they are being economical with the truth, the results are valid.

[4est]

Its more than an idle claim though, they tested with fancy equipment and posted the results, so unless they are being economical with the truth, the results are valid.

 

Economical with the truth? Well call it what you will, but their website compares their power supply noise to that of a dry cell battery, and not something like a LiFePO4 that the Stahl-Tek and Berkeley would use. There is a difference, or you would see people using regular dry cell batteries (there is nothing cheaper in the short term).

[tubesound]

I'm interested in why you thought it would. Isn't the purpose of the iUSB to improve on computer bus power? I would be pretty amazed if it helped the device you highlight given it's attention to battery power and considerable cost.

 

It doesn't hurt to have a try. I'm confused why it degraded the sound of Stahl~Tek though (I was expecting no improvement only).

 

Even with my Bel Canto uLink, I'm not sure whether iUSB improved the sound or not. With it, the background seems cleaner but the system lost some dynamics.

[Dj]

 

Even with my Bel Canto uLink, I'm not sure whether iUSB improved the sound or not. With it, the background seems cleaner but the system lost some dynamics.

 

As far as I understand iUSB should cut the dirty power coming from the computer through the USB cable and feed your Bel Canto uLink with clean power via its own switching power supply.

 

Reading your experience about cleaner background it seems to me it is doing its job exactly the way it was designed but I don't understand why the system loses some dynamics? What sort of USB cable do you use with iUSB? If it is one of those fancy one with electronics on it like AudioQuest highend cable then I would suggest try a neutral USB cable without any electronics. Or wait for iAudio to release their USB cable.

[wisnon]

Economical with the truth? Well call it what you will, but their website compares their power supply noise to that of a dry cell battery, and not something like a LiFePO4 that the Stahl-Tek and Berkeley would use. There is a difference, or you would see people using regular dry cell batteries (there is nothing cheaper in the short term).

 

Ahem:

 

 

Incidentally, they DO have a LiPo battery in their Chart on Facebook...

The LiPo has less noise than the dry cell above 50hz, but more below...

[gtener]

First impressions with iUSB connected from my music server to hiface v.1 to Moon i3.3 with built in DAC - are great! Seems like a bigger soundstage, blacker background. I'm really hearing more of the music.

[wisnon]

In the iUSB the SMPS powers a lot of internal circuitry.

 

The DC from the SMPS (which is already pretty quiet) goes then through a CLCLCLC filter (that is a 6th order or 36dB/Octave) which is Bessel charateristic and starts filtering at 150Hz and filters around 90dB at the common SMPS frequencies around 50KHz.

This eliminates any switching noise and RFI, dropping it well below -150dBV with the low noise SMPS.

 

After that filter they use a so-called "super-regulator" with a lot of trickery for very low noise. This is actually how they get "lower than battery" noise levels with the iUSB.

 

The power via the iUSB goes:

low noise SMPS ->

very LC RFI Filter ->

Super-regulator ->

DC out

[4est]

Mea culpa... I didn't look on Facebook, but their website.

[wisnon]

No probs 4est. FB is where all the action is for iFi (as well as here, LoL)....I almost never go on their Web site.

 

Here is another tidbit I picked up there:

 

Key is the Precision Voltage reference that is driven by a Constant Current Generator for maximum isolation from any supply noise.

 

This is actually how we get "lower than battery" noise levels with the iUSB... Quite complex, for a such a simple looking device.

[John H. Darkø]

 

The power via the iUSB goes:

low noise SMPS ->

very LC RFI Filter ->

Super-regulator ->

DC out

 

That's super useful info. Thanks wisnon.

[wisnon]

A pleasure John!

[tubesound]

iFi posted the internal view of iUSB: https://fbcdn-sphotos-e-a.akamaihd.net/hphotos-ak-prn1/457390_490388604330220_623625141_o.jpg

[Blake]

I thought I would include an update/addendum to my earlier review posts (posts 66, 124 and 126 in this thread).

 

I think I may have stirred up a bit of confusion in my posts 124 and 126 with respect to using the KingRex twin-headed USB cable. My apologies.

 

Long story short...

 

1. If you have an old MacBook (my MBP is a 2007 model), the KingRex twin headed USB cable works terrific with the iUSB. The only caveat is that you will not be able to select "Integer Mode" on Audirvana. That is it. Otherwise the KingRex twin headed USB cable works just fine with the iUSB on older MacBooks like mine.

 

2. If your MacBook is newer than 2007, then you can use "Integer Mode" in Audirvana with the KingRex twin headed USB cable.

 

3. If you are not using a twin headed USB cable with your iUSB, you are not hearing the iUSB at its best. Sonic improvements can be heard using a twin headed USB cable (as one would expect- that is why iFi designed this option in the iUSB). I am currently using my KingRex twin headed USB cable and the sound is improved over using a single strand USB cable.

 

4. I mentioned this in another thread but thought it would be helpful to post here as well: the Mapleshade Clearview USB cable can be used from your computer to the iUSB. However, the Mapleshade Clearview USB cable will not work from the iUSB to your DAC or SPDIF-Converter.