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

[Liam]

I love this little iusb! Even if you think your USB DAC is well designed, it's worth a listen. My DAC uses the XMOS board and vbus only powers the DAC's USB receiver. Once you become familiar with the effects of a lower noise floor, it's easy to identify. It's well made and smartly designed by AMR. Step aside AQVOX!

 

Vbus only powers the usb receiver in the M2tech Young dac, and I also found benefit. Don't entirely dismiss the Aqvox PSU though. Have you tried it in tandem with the iusb? In case you have not seen it, I posted an image earlier in the thread of how I have done this. If you give it a go and have not read my earlier reviews try it first and then compare results. Be interested to know your findings.

[dallasjustice]

Is there a correct orientation for the ifi smps to be plugged in? If the wall ground plug is 12 o'clock, I plugged it in with the power line pointing 12 o'clock.

[dallasjustice]

Vbus only powers the usb receiver in the M2tech Young dac, and I also found benefit. Don't entirely dismiss the Aqvox PSU though. Have you tried it in tandem with the iusb? In case you have not seen it, I posted an image earlier in the thread of how I have done this. If you give it a go and have not read my earlier reviews try it first and then compare results. Be interested to know your findings.

I don't AQVOX anymore. I previously found no improvement over sotm USB card. Its in a state of disrepair because I modified it to power a hard drive several months ago. My comment is based on indirect comparison previously mentioned and the ironic fact that the German AQVOX looks janky compared to Chinese made ifi.

[bpw]

Here is a photo of the iFi Gemini Dual Headed USB Cable. They are scheduled to ship to distributors in mid January. Pricing is not yet known. I have several on order.

 

Brian Walsh

Essential Audio

Barrington, Illinois

[Liam]

Here is a link to additional information on construction and design of the Gemini cable.

[Musicophile]

Here is a link to additional information on construction and design of the Gemini cable.

 

I like the "so-called audiophile USB cable" comment. if they were right, I'm happy I only bought the cheapest Audioquest...

[mdkim]

I'm also very curious about the Gemini and its performance. I'm getting very good results with the Platimum USB cable out of the iFi...if it can get better it is a must have.

[Liam]

Is there a correct orientation for the ifi smps to be plugged in? If the wall ground plug is 12 o'clock, I plugged it in with the power line pointing 12 o'clock.

 

Not quite sure what you mean. Is there no earth pin, although blanked on the smps? In Europe the three pins are provided and the earth pin is plastic. Only one way to plug it in. I assume your positive pin is on the right in the wall socket like ours? If I interpret you correctly I think you are correct in that the cable should hang straight down

.

I don't AQVOX anymore. I previously found no improvement over sotm USB card. Its in a state of disrepair because I modified it to power a hard drive several months ago. My comment is based on indirect comparison previously mentioned and the ironic fact that the German AQVOX looks janky compared to Chinese made ifi.

 

Pity a comparison would have been interesting. By the way the 'German' Aqvox is made in Taiwan. Unlike the iFi it is not meant to take front row, but it is less costly and I found it beneficial in my system. I'm pleased that my investment has not been wasted and it is complimenting the iUSB.

[mdkim]

Is there a correct orientation for the ifi smps to be plugged in? If the wall ground plug is 12 o'clock, I plugged it in with the power line pointing 12 o'clock.

 

I was told that it matters and to make sure the bulky part of the plug was oriented downward. Now, whether that means that if your ground plug is at 12 o'clock it should be upside down I don't know. I would guess yes but most of the technical stuff is above me...

[4est]

I was told that it matters and to make sure the bulky part of the plug was oriented downward. Now, whether that means that if your ground plug is at 12 o'clock it should be upside down I don't know. I would guess yes but most of the technical stuff is above me...

 

I wouldn't rely on that, but try it both ways and take a good hard listen. The neutral/hot may be reversed, receptacle upside down and so on.

[Liam]

I was told that it matters and to make sure the bulky part of the plug was oriented downward. Now, whether that means that if your ground plug is at 12 o'clock it should be upside down I don't know. I would guess yes but most of the technical stuff is above me...

 

Here in Ireland there are three pins and smps plug can only go in one way. Earth, is at the top of the wall socket and the smps cable is at the bottom when plugged in. Therefor positive is on the right as one looks at the wall socket and negative on the left. There is no option to reverse polarity, so I guess the way I have described is the recommended way.

[tubesound]

A buddy of mine came over recently and we listened to with/without iUSB in my system. He prefers without but I prefer with it. It seems iUSB slightly compressed the dynamic range but iUSB generates a smoother sound (less digital glare). I don't know whether the Gemini cable will solve the compression of dynamics issue.

[dallasjustice]

I am not sure if this is the right place to raise this question but here goes. Digital cables like short spdif are susceptible to jitter inducing early reflections. Is the same phenomenon also true with short USB cables? It appears ifi will offer a .5 meter USB cable and I thought that might be too short. I would think a .5m spdif cable would be too short but I am not sure about USB.

[ted_b]

I am not sure if this is the right place to raise this question but here goes. Digital cables like short spdif are susceptible to jitter inducing early reflections. Is the same phenomenon also true with short USB cables? It appears ifi will offer a .5 meter USB cable and I thought that might be too short. I would think a .5m spdif cable would be too short but I am not sure about USB.

 

Where did you see iFi will offer a .5M cable? By the way, their blue umbilical is just that. I haven't thought about trying another cable (between source and iFi) yet.

[dallasjustice]

Where did you see iFi will offer a .5M cable? By the way, their blue umbilical is just that. I haven't thought about trying another cable (between source and iFi) yet.

A dealer told me it would be either .5m or 1.5m and their FB page comment says they will ship a short and long usb cable.

[One and a half]

I am not sure if this is the right place to raise this question but here goes. Digital cables like short spdif are susceptible to jitter inducing early reflections. Is the same phenomenon also true with short USB cables? It appears ifi will offer a .5 meter USB cable and I thought that might be too short. I would think a .5m spdif cable would be too short but I am not sure about USB.

 

S/PDIF cables are two conductor unbalanced transmission system. If the cable is too short, the impedance is difficult to match and it's possible to get ringing. Same can be said for Ethernet, 1m minimum is needed between say a switch and PC.

 

USB from PC to DAC is a differential (3 wire) method of transmission, where long USB cables (>5m) cause problems due to capacitance and voltage drop. USB cables don't have an impedance issue, so shorter the the better. However, USB cables are different, I would have thought to have the same model and length USB Cable at either end of the ifi usb.

[ted_b]

I would have thought to have the same model and length USB Cable at either end of the ifi usb.

 

Beginning to think same thing.

[Emcee]

I would much prefer a short(very short) cable.

 

I just ordered one of these(pic) while I'm waiting for the iFi cable to happen. Someone who's opinion I respect claims he got better results with one of these than an entry level "audiophile" cable.

 

I figure the less cable spaghetti I have in my system the better it is. My iUSB sits right next to my USB converter, < 6 inches would be more than enough.

 

I believe the rule of thumb, according to Steve Nugent(Empirical) for S/PDIF is > 2m or else VERY short.

 

Strange that so many hi-end cable manufacturers offer pricey .5m S/PDIF cables. Some like Black Cat's Veloce only come in one length(1.23m) You'd think these guys would know about this jitter reflection thing.

 

So much information/BS to sort through in cable land.

 

[One and a half]

Maybe the galvanic isolation provided by iUSB helped.

 

Just going through this long thread and came across this statement. The manufacturer doesn't claim galvanic isolation, as it's usually accompanied with a figure, like 1000V from this mob.

 

ifi audio are looking at isolation with different method and for $200 asking price, their recipe is working.

[One and a half]

I would much prefer a short(very short) cable.

 

I just ordered one of these(pic) while I'm waiting for the iFi cable to happen. Someone who's opinion I respect claims he got better results with one of these than an entry level "audiophile" cable.

 

[ATTACH=CONFIG]3290[/ATTACH]

 

That looks like the ticket, if you have room behind your DAC! Rhodium, tin, gold plated is good, audiophile grade of course.

[wisnon]

A dealer told me it would be either .5m or 1.5m and their FB page comment says they will ship a short and long usb cable.

 

They are doing a poll to see exactly which 2 lengths to launch with.

 

Here is my post from the Best USB cable thread. Note the Q&A on the ideal cable length and the response:

 

Check out the soon to be released iFi Audio Gemini cable. I can be used as a straight USB cable or with the twin heads with the iUSB power. It apparently exceeds USB standards in some areas.

 

Excerpts:

 

Many USB DAC's or other USB Audio devices draw power from the USB bus for some functions (regardless of price).

 

This is the raison d'être for our iUSB Power supply. The USB cable complements and extends this and maximises system performance.

 

If you are 100% sure that your DAC does not use USB Bus power at all than you are lucky enough not to need any of this and you can use a normal cable.

 

Or you can use our Gemini Cable and just not connect the power section at all, or connect it and enjoy even lower ground resistance.

==========================

 

The Gemini Dual-Headed USB cable will ship in short/long lengths. The pricing will be in-line with the rest of the iFi range. Our beta testers have pitched the Gemini Dual-Headed cable against cables all the way up to 10x the price. Let's just say the Big Guns went home crying 'mummy'. Another iFi product with 'off the chart' performance!

=================================

 

iFi Audio's Notes

iFi Gemini Dual Headed USB Cable

Sunday

 

 

 

Features

Dual-headed (Gemini) connection USB design

Asymmetric Ground return and power line design (3 times more ground area)*

Adjustable RF Filter to tune cable to environment*

Multiple RF filters*

Heavy OFHC continues cast copper (up to 5A)

Double shields with different effective range

Custom PE insulation

*: iFi exclusive, world first.

=====================

 

Q: People like Steve Nugent say that 1.5m is the ideal length. O.5m is too short, so I pick 1 and 1.5m!

Monday at 9:11pm · Like

 

A: (iFi Audio) ‘Ideal’ length/s is NOT relevant for USB signal transfer... this comes from SPDIF and is only valid in cases where impedance mismatches occur. For High-Speed USB it simply either works or it does not. The Gemini USB-Cable strictly adheres to 90 ohm throughout which is one key USB.org specification (among many other things). Therefore, you only have to select the relevant length/s to suit your needs!

===========

 

The reason why some "handmade" USB Cables do not work with the iUSB is simple, they are not of sufficiently accurate impedance.

With a single short cable this is less damaging and the makers of such contraptions often can almost get away with murder.

 

However, as with the iUSB Power you in effect couple two cables together. In this case, if one cable has correct USB Impedance (e.g. the short blue tail included with the device) and the other has a different impedance additional reflections (on top of those at both ends of the cable) will be generated.

 

And even a robust system data transmission system like USB will eventually experience packet loss...

Sadly, the more expensive and exotic a cable is the less likely it is to be mass produced on machinery made for precisely mass producing USB spec cables.

 

It's not that we do not know how to make better USB cables, the problem is modifying standard cables for improved performance in ways that are compatible with industrial production methods and then finding someone to make such cables in moderate quantities.

=====================

 

Hi, sonic differences are indistinguishable between the shortest and longest. They all adhere to the strict USB data transfer standards (why we can offer longer lengths). Please see the 'iFi Gemini Notes' for an in-depth outline of how+why the Gemini USB cable differs.

=============

[sandyk]

If you are 100% sure that your DAC does not use USB Bus power at all than you are lucky enough not to need any of this and you can use a normal cable.

 

Really? And there will be no audible differences between the cables used, especially if +5V Vbus is not connected at the PC end of the USB cable ? That statement alone doesn't inspire confidence in me about some of their other pronouncements.It seems to me that they may have just put together better versions of a couple of things promoted elsewhere by some other manufacturers, and also discussed in C.A. previously in various threads.

Yes, use of a very low noise PSU is good, but not unique. LiPo batteries are another option.Neither is the use of higher quality USB cables with improved separation between Data and Power.The kind of boastful language used in their promotional material doesn't sound very professional either. Nevertheless, the sum of their efforts may be quite worthwhile.

Alex

[wisnon]

At the prices iFi charges (low), they can boast ll the want because the DELIVER big time. Companies like this will SAVE the industry by bringing in the iPod generation....long ignored by the high priced big box makers.

 

And oh, when he says a "normal" cable, he means a straight cable as opposed to a Y cable...not a generic computer cable vs a high quality audiophile cable. Plus, as he said, even bad USB cables, if they are short, will get away with bad impedance values.

[sandyk]

wisnon

You have already posted the same quotes in another thread.

In fact, I thought I must have been having a case of deja vu when I saw this most recent post. (grin)

Perhaps a link to their site, or the previous thread would have sufficed ?

Do you have some connection with the supplier, or are you just extremely enthusiastic about this manufacturer's products ?

[wisnon]

I said in my post above that it was from the Best USB thread...read again! Here is my post from the Best USB cable thread. Note the Q&A on the ideal cable length and the response:

 

 

I have no connections (I work in pharma, this is just a hobby)...just enthusiastic, since I LOVE the concept and pricing and a buddy got the iPhono on a whim based on my suggestion and said it bested his $5k phono stage!

 

The post got not much traction on the other thread and here is was answering a DIRECT question from Dallas J.