FiiO 4.4mm Balanced Amp AM3B impressions
- expatinjapan

Visit FiiO for more information on the AM3B Amp module.



FiiO AM3B 4.4mm Balanced Headphone Amplifier Module for X7/X7II/Q5 Music Player

Specifications via Penon Audio


Bask in the beauty of 4.4mm balanced

Enhanced balanced/ Single-ended amplifier module AM3B

The AM3B 4.4mm balanced/3.5mm single-ended output amplifier module is based on the AM3A,but has received key enhancements over it. Like the AM3A, which has proven to be a hit among audio enthusiasts, the AM3B also uses the highly-acclaimed AD8620 wide-bandwidth precision JFET operational amplifier in conjunction with two tailor-made OPA926 op-amps.
However, from here the differences begin. Exterior-wise, due to the extra length of the 4.4mm socket we could not use traditional layout techniques as this would result in the jack undesirably protruding from the rest of the amp module. In order to resolve this issue, FiiO engineers came up with some clever packaging involving two stacked PCBs that not only ensures we can fit a 4.4mm socket within our amp module, but also allows for further protection of the audio circuit contained in the module itself. In addition, a metal ring surrounding the 4.4mm jack also adds further strength to the connection.

Interior-wise, due to the two stacked PCB design's space savings the AM3B audio circuit design has some key enhancements over the AM3A. With the AM3B, we have been able to fully isolate the amplification and power supply sections, further optimize the power supply, and increase post-amplification stage operating voltage to 4.5V. All of these changes result nearly 100mW more of power in balanced operation.

Using the screwdriver included in the accessories of X7/X7 Mark II/Q5 to unscrew the T5 screws and exchange the headphone amplifier module. Although protection circuits are installed on the X7/X7 Mark II/Q5, it is still recommended to perform module exchange while the unit is turned off.
X7 Mark II (with AM3B) +F9 PRO: Due to physical size differences stemming from the 4.4mm jack, the AM3B does not fit into the X7 Mark II's original silicone case. Thus, included in the AM3B is a specially-made silicone case.


Balanced headphone out specifications (4.4mm balanced headphone out jack)

Output power ≥420mW (16Ω/THD+N<1%)
              ≥498mW (32Ω/THD+N<1%)
              ≥70mW (300Ω/THD+N<1%)
Frequency response:7Hz-57kHz (-3dB)
Output impedance <3Ω(32Ω loaded)
SNR ≥119 dB(A-weighted)
Channel separation >106dB(1 kHz)
THD+N < 0.001% (1 KHz)
Peak output voltage >11.8 Vp-p
Max.output current > 150mA (For reference)
Driver ability: 16-300Ω
Noise floor <6.5uV
Headphone out specifications (3.5mm headphone out jack)

Output power  ≥296mW (16Ω/THD+N<1%)
               ≥158mW (32Ω/THD+N<1%)
               ≥18mW (300Ω/THD+N<1%)
Frequency response:7Hz-57kHz (-3dB)
Output impedance <1Ω(32Ω loaded)
SNR ≥118dB(A-weighted)
Channel separation >72dB(1 kHz)
THD+N < 0.001% (1 KHz)
Peak output voltage >6.4 Vp-p
Max output current > 150mA (For reference)
Driver ability: 16-150Ω
Noise floor <4uV


Around US$100 


Is it impressions or a review? Well a bit of both really. The AM3B being an amp and a part of a whole system the Q5, X7 and X7ii. 

The FiiO AM3B amp DOES have single ended and balanced outputs, but I am going to go out on a limb here and guess/assume most will be buying this particular amp module for its 4.4mm. So I will mostly concentrating on that.

The 4.4mm wave is upon us...
"We can rebuild him. We have the technology. We can make him better than he was. Better, stronger, faster."

I tend to use 4.4mm more and more recently. I like the amps I have that have 4.4mm. Many cables now are terminated to 4.4mm and Sony daps and iBasso amp modules are all surfing the excitement.

Is it better in sound than 2.5mm, some say yes, others no. Both camps agree that it is stronger plug and has more connective surface. I myself have not had any 2.5mm plugs break on me yet "touch wood".

so onto the FiiO AM3B amp module. It certainly is affordable at around US$100. Can`t complain there. And with several companies making decent 2.5mm to 4.4mm adapters one can maneuver around buying more cables or re-termination.

FiiO BL44 2.5mm female to 4.4mm male plug adapter

So whats the secret sauce? is it the 4.4mm? the insides of the amp its self, a synergy between the aforementioned and also including the FiiO X7/X7ii daps or the FiiO Q5?

Well no use delving too deep as it is an add on, I find amplifiers to color the sound more than dacs these days, especially as many companies are moving towards a more neutral sound and low output impedance - even the AKM/Sabres differences are less prominent than earlier.

Which brings us back to these marvelous daps with changeable amp modules. One can tailor the sound to one liking more easily within one system, and also choose a termination that one prefers and also the power output whether one is using sensitive IEMs or full sized headphones.

The FiiO AM3B tries to straddle both camps.
The specifications tell the story, but to many readers its all incomprehensible gibberish. So lets break it down as usual into readable bullet points now that my usual initial ramble has passed.

The FiiO AM3B is a clean, fairly neutral amp with a slight warm tint to it, mostly in the mids.
It has an output impedance of 3ohms on the 4.4mm which did give me a bit of surprise as 1ohm or less seems be the industry standard these days, or 2ohms at a stretch. I did not notice too much, just a bit less bass at times with some IEMs. (The SE OI is lower).
As mentioned before it has more power than the stock amplifier. As a result it may have some hiss with more sensitive IEMs.
The main plus is a larger sound stage than the stock amp, it also has more dynamics although slighter smoother so there is some loss of definition although this is compensated by better texture, layering and more separation overall.
It has better control and more of a sense of space and spaciousness over the stock amp.

It is quite similar in sound to the stock amp but just goes the extra step further and with it bringing the main units more up towards a totl sound.

I enjoy it and now have it permanently in the X7ii.

Thank you to FiiO for sending the AM3B for impressions and review

Three years of word salad reviews, crappy ipod touch 6G photos (oh yes!) and funny then regressively more and more salty memes