i.Fuzen HP-1 # (Sharp - Black)

iPhone 4/4S Case with Built-in Headphone Amplifier, Splitter and Extended, Rechargeable Battery


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Increase Your iPhone's Battery Life

Double Your iPhone's Battery Life

The HP-1 has a powerful 1650mAh on-board backup battery which can nearly double the battery life of the iPhone 4/4S. The unique Smart Battery Protection circuit continuously monitors and optimizes the power performance of your iPhone, and an independent LED indicator keeps you informed of the remaining life of the secondary battery. The new "auto shut-off" feature will help preserve your battery life by switching off once the iPhone is fully charged.

Headphone Splitter

Headphone Amplifier & Splitter

The i.Fuzen HP-1 allows you to share your music with a friend by splitting the single headphone jack into two. The proprietary J-FET OP-AMP amplifier is powerful enough to drive two pairs of standard headphones or one pair of professional monitoring headphones while maintaining vacuum tube quality sound, making the HP-1 the ideal choice for audiophiles and music lovers alike. The new and improved amplifier will allow you to enjoy the headphone amplifier while your iPhone charges.

iTunes Sync

Unrestricted iTunes Sync

With full USB pass through capability, this case will allow you to sync flawlessly with iTunes without the need to remove the iPhone. The mini USB input also increases your options if you are in need of an emergency charge, but do not have access to a dock connector cable.

Innovative Design

Innovative Design

The i.Fuzen HP-1 takes advantage of the features and style of the iPhone 4/4S. The relatively sleek case accentuates the iPhone's distinctive lines while minimizing the increase in overall size. The HP-1 is available in white and black, allowing you to easily match the case to your iPhone.

Cell Phone Case Features:

  • Proprietary Auzentech Headphone Amplifier
  • Dual Headphone Output port to share your listening with your friends
  • ZX-Driver provides Ultra-Low Distortion and Max 180mW output power
  • J-FET OP-AMP to provide Vacuum Tube like sound output
  • Proprietary Auzentech Balanced Power Supply
  • Sound Mode, Selector button & Status Indicator
  • Touch panel volume control
  • Unique & compact design to match your iPhone 4 look
  • Impressive 1650mAH Li-Polymer battery with Smart protection circuit
  • Improved Sharp Version adds innovative features
    • Unlimited headphone amp usage while your iPhone is charging
    • Headphone amp will not charge iPhone while in use for extended usage
    • Automatically shuts off once iPhone is fully charged to extend battery reserve power
  • 4-Steps LED battery life meter and battery life check button
  • Charge via USB port (from desktop PC or Laptop) with supplied USB cable
  • Supports USB pass through, iTunes Sync
  • Last up to 500 full charges
  • Color: Black
  • Also available in: White
  • Authorized Internet Dealer
  • 1-year Manufacturer's warranty
iFuzen HP1 battery life chart

Device Specifications:

  • Battery Life: 1650 mAh
  • Supports USB pass-through
  • Output voltage: DC 5V
  • Output current: 500 mA
  • Maximum Input current: 800 mA
  • Output Power: 180mW (90mW + 90mW @ 32 Ohms
  • Frequency Response: 5Hz - 100kHz, +/- 0.23dB
  • Input Sensitivity: 1.25V RMS
  • Maximum Gain: +9dB
  • Input Impedance: 50 kOhms
  • Load Impedance: 32 - 600 Ohm
  • Total Harmonic Distortion: 0.002%,@ 1kHz into 32 Ohms
  • Signal to Noise Ratio: 113dB (A-weighted)
  • Product size : 62.7mm(W) x 133.4mm(H) x 15.3mm(D)
  • Weight: 70g

Battery Specifications:

  • 1650mAh rechargeable lithium polymer battery
  • DC 5V/500mA Power output
  • Audio playback Up to additional 44 hours
  • Video playback Up to additional 11 hours
  • Talk time Up to additional 8 hours

Headphone Amplifier Specifications:

  • 180mW Headphone output power
  • 32 - 600 Ohm Load impedance
  • 113dB(A-weighted) Signal to noise ratio

Compatible Cell Phones:

  • iPhone 4
  • iPhone 4S

Key Features And Comparison Chart

Unlimited Headphone Amp Usage While Charging
Longer Headphone Amp Usage
Auto Shut-Off To Extend Battery Reserve
4-Step LED battery life meter
Touch panel volume control
USB Input For Increased Charging Options

Product History:

i.Fuzen HP-1-#-SHARP-BLACK thumbnail
(newest, current model)
i.Fuzen HP-1-BLACK thumbnail
(previous model, replaced by i.Fuzen HP-1 # (Sharp - Black))

General Features

Case Type
This is the type of case for your cell phone. Fitted cases attach directly to the cell phone and provide a tight fit. Universal cases usually have a pouch or clam-shell fit that will provide excellent protection for many different types of cell phones.
Compatible Cell Phones
These are the cell phones that are compatible with the accessory. If you see your phone listed here, then this device is compatible with the cell phone.
Apple iPhone 4
Apple iPhone 4s
Primary Color
This is the main color of the item.
Clear Screen Cover
Protects your screen from scratches, bumps and cracks.

Warranty and Return Policy

Parts Warranty Duration
1 year
Labor Warranty Duration
1 year
Warranty Provider

Summary of Customer Ratings & Reviews

Rating Distribution

5 Star
4 Star
3 Star
2 Star
1 Star

Average Attribution Rating



iFuzen HP-1# Sharp

February 9, 2012

I purchased two of these units, one as a present and have used the unit with the Real Voice Spider ear buds. I made sure to follow the instructions regarding first time charging and had no problems from the first connection on.

I first connect the Real Voice Spiders directly to the output of my iphone 4S and listened to several selections, primarily Jazz, classic rock and blues. All recordings were at least 256 bit and i set the all parametric values to flat. The sound from the iphone 4s output jack was average at best (apple should really be ashamed) even with the Real Voice Spiders which are a substantial (understatement) improvement from the earbuds supplied by apple. I then plugged in the iFuzen (no break in) and connected the Spiders to the Low output side (there is also a hi for difficult to drive headphones such as my HD800s).

The sound improvement with the iFuzen/Spiders was DRAMATICALLY better in every way. I then connected my HD 800s to the hi side of the iFuzen and again listened to the same selections, incredible. The iFuzen/HD800 combination (on these 256bit songs) was so close to my dedicated head phone amp (Audio GD NFB 10WM) it was almost impossible to tell the difference. The iFuzen had a little more bloom (tube warmth if you will) and a slight emphasis in the mid to low bass register (quite pleasant and relaxing actually) and the Audio Gd had a higher level of resolution but these are all insignificant and quite frankly, the iFuzen is easier to listen to with lower resolution media.

The iFuzen has a sound shaping feature witch allows the user to select between 4 different effects. They did have an effect on the sound but i prefer my music as recorded so i have not explored it other than to run through all the selections once or twice per song to test it.

I have read some complaints about the volume control on the iFuzen but at least i have not had any problems with it (it appears as though some had not read the manual).

Things to watch for:

1 when you plug the iFuzen into your mac (or whatever) with the supplied cable it turns the unit on. Once charged or synced and the cable removed, the unit must be turned off manually or it will drain to the iphone until empty. I have never had any problems syncing with my mac once iTunes is started.

2 when plugged in to the mac, it doesn't always fire iTunes off (if you have iTunes set that way) but it does always start charging.

15 of 18 found this helpful

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Dallas, TX

iFuzen Black

February 20, 2013

It's a great case/battery for the iPhone. It doesn't provide any protection for the iPhone screen and it does add some weight to the phone. But, I've attached the "Rivet clip system" to it so that I can attach it to my belt or belt loop. Pair the iPhone. iFuzen and the noise canceling Bose headphone and you get a terrific sound with double the play time, and the option of a second set of headphones or earbuds for your travelling partner.

13 of 15 found this helpful

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New Braunfels TX

Nice case

May 8, 2014

This is even lower in price now!!! At $19 its a steal.
It does amplify headphone signal and does give you about a 70% charge to iPhone.

8 of 10 found this helpful

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Lancaster, CA

Great product

February 8, 2012

Really useful case for those days out with the family and your not going to be able to charge the phone. Other cases cost way more and don't give the hours of life this case can. This case, it's a must buy.

7 of 11 found this helpful

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Product Summary


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Sonic Electronix Wiring Guide

Wiring Diagram Legend

Warning: The image depicted shows the resistance change when wiring multiple subwoofer terminals. Please refer to your subwoofer's owner's manual for the proper wiring of its terminals. Sonic Electronix, Inc. is not responsible for damage caused to your audio system or vehicle due to improper installation. Please call tech support at 1-877-289-7664 if you require additional assistance.

Product Name: i.Fuzen HP-1 # (Sharp - Black)

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i.Fuzen HP-1 # (Sharp - Black)

iPhone 4/4S Case with Built-in Headphone Amplifier, Splitter and Extended, Rechargeable Battery


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