Fiio E9 Desktop Digital USB Headphone Amplifier Review

July 10, 2012

Fiio E9 Desktop USB Headphone Amplifier

MSRP $129.99 (much cheaper online at Amazon) 



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The Fiio E9 Desktop Headphone Amplifier is designed to give you more ooomph or power for higher end headphones that are more power hungry, but this Headphone Amplifier is a great bargain to get better sound from your computer thanks to the output power of 1watt at 16 Ohms or 800mW at 600 Ohms. This Headphone Amplifier can be used in multiple modifications – either in your home audio system with passive loudspeakers or in your computer area with either headphones or both active and passive speakers

I bought the Fiio E9 Headphone Amp for one reason, and one reason only: I wanted a big and easy to use volume button without having to adjust the computer’s volume via keyboard or a mouse. The extra amplification with the highly regarded Burr Brown OPA2134 Op Amps was really just a bonus. Another reason to buy the Fiio E9 is the fact that it plays very nicely with the Fiio E7 USB DAC  I reviewed recently and results in a powerful headphone amp and DAC all for under $200 on sale.

The Fiio E9 Headphone Amplifier is finished in anodized aluminum and feels like a sturdy audio device with a weight of 445 grams, this has a very good feel for it and doesn’t feel light and cheesy at all.


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The front of the Fiio E9  is where you’ll find yourself interacting with the unit the most and the design could not be simpler: A big smooth volume button that takes up almost the entire front of the unit accompanied by two headphone jacks – one for 1/8 (3.5mm) and one for 1/4 (6.35mm) connectors. There’s also a power indicator light that when first turned on glows red for one second, and then switches to blue. I’m not sure why they designed this other than to indicate that at first it gets power and then a second later it’s ready to use? When you turn the power off to about 7pm (as in photo above) the power light obviously goes out too.

I have two complaints about the Fiio E9’s front. One, after a few months the volume got scratchy when adjusting – it probably only needs to be cleaned with  a can of air or possibly contact cleaner, but I have only had this a few months and other items I have owned that have knobs and switches do not seem to be affected by dust  like the volume knob on the Fiio E9.

The other issue I have is the indented ports on the headphone jacks sometimes mean the headphone jack can easily pop out or it can be hard to seat the jack. This holds especially true with the 1/8th mini jack. I hope that on future products Fiio decides to omit this and sit the headphone jack inputs flush, the same as they are for the 3.5mm ports on the back of the unit.



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Speaking of the back of the unit, there’s more than one way and one port on this headphone amp:

Line In This port allows you to hook any line output to the Fiio E9. For example, use one of the outputs on your home stereo connected to this port and you can use the headphone Amp with your home audio stereo if it lacks a built in headphone amplifier and output, and even if it does the Fiio E9 will probably sound better anyway. You will need a rca to 3.5mm adapter cable (not included) to do this. I wish Fiio had also included a RCA left/right input instead of making the input a 1/8inch headphone jack.

Pre Output This allows you to connect the fiio headphone amplifer to an amplifier and use this as a pre-amplifier. You could, for example connect your iPod to the line in port, and connect the pre-out port to an amplifier and use the fiio as a preamplifier. The output from this would be a fixed output, and would bypass the volume control on the Fiio E9. You would use the volume control from your amplifier or if applicable – your source.

Line Out This port allows you to output the sound via a 3.5mm port to an amplifier, and unlike the pre-output option, this allows volume adjustment via the volume knob on the front of the headphone amplifier.

Gain Switch This is pretty self explanatory. If you have sensitive headphones you won’t need the extra gain, but if you have high impedance headphones flip the gain switch to the up position.

USB Input This allows you to connect your computer to the headphone amplifier, but this only works if you** buy the Fiio E7** as well and connect it to the dock (see the photo below) . If you don’t and plan on using it just with a line in, you’ll still get the benefits of the headphone amplifier but miss out on the functionality the USB IN provides

Power Input Pretty self explanatory – you need to plug it in using the included power adapter (see photo below)


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The top of the Fiio E9 offers one connection and it’s proprietary and only works with other Fiio DAC’s like the Fiio E7.  I have both the DAC and this amp, and it’s a match made in heaven as the amplifier charges the fiio E7’s battery so when you need to use the Fiio E7 as a portable headphone amplifier you’ll be all charged up and ready to go. When the Fiio E7 is plugged in, the amplification comes from the Fiio E9 and not the Fiio E7. You’re using the Fiio E7 as a DAC only when docked into the Fiio E9.


What’s in the Fiio E9 Box

The Fiio E9 Box



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Fiio E9 AC Power Adapter 


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Fiio E9 USB Cable with Ferrite Core


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Fiio E9 Specifications 

The biggest specification is more power for your headphones than you could get out of your iPod, smartphone or notebook computer. This is the perfect companion for more power  hungry headphones. The Fiio E9 ships with loads of power. Using Sennheiser HD 25’s I am never able than to go louder than 9 o’clock on the dial for comfortable listening. The texas instruments TPA6120 amplifier offers loads of room and with a total harmonic distortion of 0.00014%, the Fiio E9 offers clean sound.

Two Channel Power output via line out, or 3.5mm and 6.35mm headphone jacks.

On/Off and Mute functions uses sealed relays and and ALPS sealed low noise potentiometer

BB OPA2134 audio butter with low noise, low distortion (0.0008%)

Buit in Dock for other Fiio products

Two Audio Outputs: 3.5 mm adjustable line output, and RCA fixed output

LED power indicator

Headphone Output priority. Plug a headphone in, and the outputs on the rear mutes automatically.

Output Power: 1W at 16 Ohms, and 80mW at 600 Ohms

Headphone Impedance: 16-600 Ohms

Signal To Noise Ratio: 100dB

Total Harmonic Distortion: 0.003%

Fixed output: 2v rms

Adjustable output: 0-2v rms

Power Supply: DC 15v 1.5A

Size: 149mm x 96mm x 56mm

Weight: 445g

Fiio E9 Connection Options

Probably one of the bigger features of the Fiio E9 is the choices on how you can use it. Using the USB IN or Line IN, you have six different connection options: (USB In requires purchase of Fiio E7)

Line In Connection Choices

  1. Source via 3.5mm out to 3.5mm line in to 3.5mm or 6.35mm headphones

  2. Source via 3.5mm out to 3.5mm line in to 3.5mm line out to amplifier to speakers

  3. Source via 3.5mm out to 3.5mm line in to 3.5mm line out to active powered speakers

USB In Connection Choices

  1. Computer USB to USB IN to 3.5mm or 6.35mm headphones

  2. Computer USB to USB IN to 35mm line out to amplifier to speakers

  3. Computer USB to USB IN to 3.5mm line out to active speakers


For the money (usually under $100) this is a good looking headphone amplifier that looks good and sounds even better  – especially when paired with the Fiio E7 that it was designed for. I find myself listening to music I haven’t played in years, because the sound is so clear than the sound output I have been used to by using my MacBook Pro’s headphone amp. I really,really appreciate the old school volume control where a quick tweak of the dial adjusts volume control without me having to stop my workflow to find a sound menu or keyboard button – this feature alone is worth the price and makes computer audio much more enjoyable.

On good recordings, the sound and power output are nothing less than breathtaking. On lesser recordings this device, like a lot of audio devices that are high quality and don’t color the sound at all will want you to stop listening, but this is the fault of the original recording and not the Headphone Amplifer. With high quality parts from Texas instruments and with processors and chips usually reserved for high end audiophile equipment costing much more, the Fiio E9 (and matching Fiio E9) could be the best bargain in headphone amplification and listening this year.

Where To Buy the Fiio E9 Headphone Amplifier

I bought mine at Amazon, and I ask that you do too.

I feed my family with this site. I buy my own stuff to review here and I don’t have a trust fund. I just like to shop for the best prices on stuff and write about it and photograph it. When you buy from Amazon you help pay for hosting costs and well, feed us. This costs you nothing to do and when you buy from Amazon, almost every product I write about whether it’s memory upgrades or digital cameras, you’ll get a better price and return policy than almost anywhere else. Buy the Fiio E9 On Sale Now