iFi Audio Micro iUSB Power

iFi Audio micro iUSB Power este un sistem de alimentare a dispozitivelor conectabile prin USB. micro iUSB Power este alimentat cu tensiune de la retea. El preia transmisia de date din conexiunea USB si inlocuieste la iesire tensiunea de alimentare din computer cu cea obtinuta din circuitele proprii de redresare. Sunt disponibile doua iesiri - o alimentare simpla si o conexiune mixta de date si alimentare.

Alimentarea echipamentelor audio este un factor care poate face diferenta dintre un produs excelent si unul mediocru. Circuitele de alimentare sunt esentiale mai ales in cazul aparatelor alimentate prin USB ( DAC, amplificatoare de casti sau miniboxe USB ). Conexiunea USB este comuna pentru semnalul audio si pentru alimentarea cu tensiune, ceea ce face USB atractiv prin simplitatea lui in cazul stickurilor, HDD externe sau tabletelor, dar complica mult lucrurile in cazul dispozitivelor audio. Atat modul in care este tratata conexiunea in computer cat si utilizarea aceluiasi cablu pentru a transmite semnalul util concomitent cu alimentarea dispozitivului induc un "zgomot" care altereaza sunetul. Utilizand micro iUSB Power, sunetul poate castiga in dinamica, naturalete si rezolutie. 

fara iUSBPower	cu iUSBPower

iFi au depus eforturi sustinute pentru a obtine o sursa de alimentare atat de curata. Unele dintre tehnologiile utilizate se bazeaza pe experienta acumulata de firma mama, Abbingdon Music Research. Sursa propriu-zisa de alimentare cu 9V este conceputa special pentru aplicatii audio. iUSB Power foloseste un circuit numit "Super Regulator" pentru a redresa si filtra tensiunea, cu o precizie de 0.5%, mai precis decat o baterie de 9V. 

"Zgomotul" sursei de alimentare :

IsoPower este un sistem complet nou de conexiune a dispozitivelor audio USB. Este folosit pentru a elimina interferentele dintre traseul de date si cel de alimentare. El poate fi pus in valoare la maxim cu ajutorul cablurilor USB iFi Gemini, care folosesc doua cabluri distincte pentru alimentare si date. Acesta este un principiu clasic folosit in instalatiile electrice: nu se amesteca traseele de curenti slabi cu cele de putere fiindca apar interferente nedorite.

Iso Earth este un alt circuit conceput special pentru micro iUSB Power. Acest circuit izoleaza masa deviceului care este alimentat prin USB de masa computerului la care este conectat. Astfel, "zgomotul" este redus cu un ordin de marime si dispozitivul audio poate opera intr-un mediu lipsit de interferente nedorite.

Headphone.Guru :

"Now I was getting curious about the iUSB given the iFi success so far. I plugged this device in after a week and a half of burn-in. It made the most difference of all in my system. The noise floor lowered and the Amarra playback sounded more analog-like. It was a welcome improvement."

Positive Feedback :

"The improvements in overall quality are profound enough that I can't imagine running a USB DAC without it. You just don't realize how noisy and congested a USB DAC might be when powered straight from a PC's USB port until you hear one running noise free powered by this clean dedicated power supply. To paraphrase Joni Mitchell, you don't know what you've got till it's gone. Simply put, an essential part of a USB based computer audio system.

The Absolute Sound :

"In my nearfield desktop system replacing the stock AC power supply with the iUSBPower lowered the iDAC’s already low noise floor to the point where it sounded very much like what I’m used to hearing from a live microphone feed. Micro-dynamics seemed more pronounced when the iUSBPower was attached and the smallest details buried in the mix were easier to hear."

Digital Audio Review :

"Now we have USB-S/PDIF convertors to lick jitter and the iFi iUSB Power to take care of the electrical noise. The illustration on the back of the box visually summarise the gains heard by this reviewer. It's not just marketing puffery"

Stereophile :

"Inserting the iUSBPower between my computer and the iDAC produced various and subtle changes. With Gillian Welch's remarkable "Dark Turn of Mind," from her The Harrow & the Harvest (ripped from CD, Acony ACNY 1109), the reportedly cleaner power supply produced a clearer sense of force in the note attacks of both Welch's and partner David Rawlings's guitars, and a better, clearer spatial presence to her voice, all without apparent penalty. To hear how the iUSBPower might affect music of wider bandwidth, I turned to that favorite chestnut, Led Zeppelin's wonderful "Since I've Been Loving You," from the fancifully titled III (ripped from CD, Atlantic A2-19128), and listened appreciatively as the iUSBPower allowed greater depth and power to the wonderfully big, undamped sound of John Bonham's bass drum—and, at the other end of the spectrum, imparted greater clarity and insight to the words Robert Plant sings as well as Jimmy Page's softer guitar noodlings."