Portable Amplifiers from the Far East: Firestone Audio Fireye HD & Tralucent Audio T1 (Lots of Pictures!)
Feb 2, 2013 at 6:34 AM Thread Starter Post #1 of 17

tomscy2000

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Portable Amplifiers from the Far East...
 ​
 
I would like, firstly, to declare that my experience with portable amplifiers has been limited. I’ve heard my fair share of them, but have never made them a priority, primarily because I didn’t like carrying them around, regardless of how light or small they were. Instead, I opted for DAC/amp combinations that could run off my laptop via USB. Despite being tethered to the computer, my current iBasso D7 Sidewinder is a joy to use. However, its laid-back sound signature, while very competent, left me looking for alternative flavors at times (not all the time). The USB rail power it used also introduced some dirty noise into the analog output stage. Thus, I began looking at potential portable amplifiers that could complement my system.
 
There are a lot of options, obviously, for a portable amplifier --- almost too many. I decided to first turn locally for some of these options. Firestone Audio is a local company and they've had a good track record of putting out good, neutral-sounding products. By an off-chance, I had the pleasure of trying out the prototype boards for their Fireye HD, so I was curious to try the final version. The T1, from HK-based Tralucent Audio, has been making waves as a quality amplifier, and I had the opportunity to test it out alongside their high-end IEM, the 1Plus2.
 
*There may possibly be a third entrant in my search for a quality amplifier, but I don't want to get my hopes up, because there are extremely few points of sale outside of Japan and Korea.*
 
My review will be geared toward the drive of portables; while I do have a full-sized headphone in the Sennheiser HD598, it’s not a particularly difficult load to drive. Most of the time, I use highly-sensitive IEMs; as a result, I value low volume performance as much as driving power. Subjective sonic assessment was made primarily via a pair of HiFiMAN RE-262 earphones; its 150 ohm impedance makes it a versatile reactive load for a variety of headphone amplifiers, while not actually being particularly difficult to drive. I did not do any RMAA tests, nor will I be doing so.
 
Feb 2, 2013 at 6:34 AM Post #2 of 17
FIRESTONE AUDIO Fireye HD --- Clean, Clear, and Effortless
 
 
Firestone Audio is known as a value brand in the world of headphone amplifiers and audio accessories. The Taiwanese company has made a name for itself making the "Cute" series of small, box-type amplifiers and power supplies. However, over the last couple of years, it has been a little silent with product announcements. Only recently did it come out with an entirely new line of products, beginning with a revamp of the Fireye line.
 
'Fireye' has been Firestone's portable amplifier line --- I bought their Fireye Mini a couple of years ago and thought it was quite nice, but the size was almost too tiny and I didn't really know what to do with it hanging off my iPod. However, the new Fireye line was a completely new endeavor, and seemed to signify that Firestone turning over a new leaf. I was instantly interested.
 
Even with the 'Cute' series, Firestone never really caught my eye in terms of aesthetics. Its products were always very 'function first', and frankly, pretty bland when it came to looks, unlike offerings from ALO Audio, Schiit, and the like. Perhaps it's just a late bloomer, but Firestone has definitely caught up in the design department. The Fireye HD looks and feels great.
 
Its front fascia is fully symmetrical and the circuit board is wrapped in a substantial, seemingly laser-cut block of aluminum. Its fit and finish is as good as any that I’ve seen --- the power, bass-boost, and gain switches click positively and the volume knob is buttery smooth. The brushed aluminum case is textured differently on the top face, forming a sandblasted matte look that contrasts well against the traditional brushed finish of the title panel and the other faces of the case. The text printed all over is very high quality and shows no signs of corner cutting.
 
At ~150g, it is a solid, solid product --- substantial, but not exactly heavy, either. The footprint of the Fireye HD is almost exactly the same size as my second generation iPod Touch, and is only 1.5 cm thick, so it is well-classified as a portable headphone amplifier.
 
 
The front fascia and back panel are held together securely by four hex screws; at the back are a DC 5V jack and mini-USB port for charging. Why the redundancy in charging ports? Firestone claims that, through the DC 5V input, "fast charging" to 80% capacity for its internal Li-ion battery can be achieved within 2 hours (faster in my experience), while charging from an empty battery takes 6 hours via USB. Operation is fully allowed during operation for both ports, and overcharge protection is built in, switching to external DC power when charging is completed to allow the Fireye HD to run purely off wall power if a user so chooses.
 
 
At the front, low gain is 1.5× and high gain mode is at 5× --- I would’ve preferred even lower gain for more play on the volume pot for IEMs more sensitive than the RE262 (almost every single one, but honestly, I'm probably way too fastidious about volume control and the only things that would satisfy me would either be stepped attenuators or digital volume control), but low-gain mode gives me more than enough to work with at normal listening volumes, even with the sensitive Heir Audio 4.A.
 
Bass boost sits opposite the volume knob; it only provides single stage functionality (I think it's +2.5 dB @100 Hz, but will check with Firestone for exact numbers) but in my experience, that's all anyone really needs, especially when it's dialed in right. When I heard the prototype board, the bass boost wasn't the most refined and frankly sounded a bit bloated, but the final version sounds much more polished. The boost has enough tightness that it doesn't bloat, but is generous enough to give listeners a definite change in sound signature. Most of the time, though, I just keep it switched off, as I suspect most head-fiers would, as well.
 
When it comes to sound, the Fireye HD doesn't disappoint. At $399 USD (now slashed to $349, and €199), it is definitely no longer a value-conscious product, and while it's not priced as a premium item through and through, it certainly has aspirations of being one and definitely delivers on those ambitions in the sound quality department. I'm no expert on amplifier circuit design, but I do believe the Fireye HD is a very nice implementation of TI's powerful and capable TPA6120, a very wide-bandwidth IC built on a current-feedback architecture with low distortion, high dynamic range (>120 dB), and fast slew rates (1300 V/µs
eek.gif
). The TPA6120 is also used in amplifiers such as the FiiO E9, ASUS Xonar series, and by DIYers looking for cost-effective reference designs. The Fireye HD does well by delivering a dynamic range of 113.7 dB(A) and a THD% of only 0.0005%.
 
As per Firestone's MO, the overall sound of the Fireye HD is clear and neutral (Firestone states +0.02 dB @40 Hz, and -0.14 dB @15 kHz when tested with a 1 kHz sine wave, at 2 Vrms output). It's highly impressive, and when you give it a deeper listen, you'll notice that the Fireye HD is very much as transparent as the source you feed it. Some brands throw "HD" around as a buzzword, but the Fireye does indeed have high definition.
 
With it, I can hear layering and a depth to the stereo image that I can't in my D7 and its well-regarded OPA1611-based output, and much less from offerings from FiiO, Styleaudio, or Audinst. Driving headphones with it felt pretty much effortless, on low or high gain. Transients feel ultra quick (this was apparent to me even before I knew the Fireye HD was based on the super-fast TPA6120). It casts a tall, deep, and wide stereo image, and I couldn't notice any problems playing soft or loud, whether it was through the RE262, the HD598, or the Fidelio X1.
 
There is no hiss at all with the Fireye HD; even with the most sensitive IEMs, I could not pick anything up, with the exception of a high frequency hum when the volume knob is turned way up on high gain. At those SPLs, though, even on a full-sized headphone, the output would sooner destroy your ears than it would take for you to complain about the hum.
 
The one real issue that I can think of with the Fireye HD has to do with the output impedance; for the TPA6120, TI recommends a 10 ohm series output resistor to isolate reactive loads, and thus, the Fireye has 10 ohms of output impedance built-in. While not a problem for the 150 ohm RE-262, most in-ear monitors are going to run into problems with the output impedance. Compared to the output of the D7 (which has <1 ohm of output impedance), I could hear a small, but significant difference in the tonal balance of my 4.A and FI-BA-SS when I plugged them into the Fireye HD.
 
It's a shame, really, that the TPA6120's wide bandwidth and speed requires current overload protection in such a way; otherwise, the Fireye HD would've been a near-perfect portable amplifier. With high impedance loads, however, the Fireye HD is simply sublime. It's too bad that most balanced armature-based IEMs range between 8 and 50 ohms in impedance (and sometimes drop even lower in the lowest bass regions) and are simply unsuitable loads for the HD to drive. Only something like the ER4P/PT (which actually benefits in tonality from electrical underdamping) may possibly sound better with the Fireye HD, as well as high-impedance IEMs like the Heir Audio Tzar 350. Thus, the Fireye HD as an amplifier is best suited for high-impedance cans and portables, as well as dynamic insert earphones less affected by electrical damping (very linear impedance response).
 
The second, less crucial issue is the battery life; Firestone lists the battery life as 5 hours under continuous usage, which is not great if you take it outside for long periods of time, but is perfectly fine if you need to use it for head-fi meets and such. In my tests, continuous usage lasts over 5 hours, and the LED in the back will begin to flash red when it's time to give it another charge. With the DC wall wart (or any compatible DC 5V power supply), you can leave the Fireye on wall power at the desk and not have to worry about battery life. Another interesting feature of the Fireye HD is that it never really fully turns off. Even when the power switch is in the "OFF" position, if you turn the volume pot way up, you'll get a significant bit of volume coming out of the amplifier. I believe this feature is part of the "pop" protection circuit for cycling power implemented by Firestone (the protection circuit is built into the TPA6120, but requires the manufacturer to take full advantage).
 
Overall, the Fireye HD is a very, very capable portable amplifier worthy of mention amongst the others. Firestone has created an amp that provides a powerful, effortless ouput stage, wrapped it in a very attractive exterior and combined it with useful features. It's about to get even better, too --- word is that Firestone is readying a balanced version of the Fireye HD; it features a proprietary balanced plug but includes multiple adapters for Kobiconn or XLR users. I believe this version is probably going to be even more appealing to folks that use portable amplifiers for full-sized headphones. Be on the lookout for when the balanced version gets released.
 
Additional Photos:
 
 
 
 
Feb 2, 2013 at 6:34 AM Post #3 of 17
Tralucent Audio T1 --- Crisp, Powerful, Centered
 
 
The T1 is a little amplifier; its footprint is only about 75% the size of an iPod Touch, though at nearly 2 cm thick, it's a little portly. The two-piece brushed aluminum enclosure keeps the weight down, thankfully. I find the T1 great to hold in the hand, though I trouble to think of situations where I would have to hold it that way during actual usage. Included is also a thick and robust-looking 3.5mm interconnect, which is a rarity, since normally, included interconnects are quite flimsy and cheap-looking (as with the case of the Fireye HD), or that one isn't included at all.
 
The entire look of the T1 is geared toward function. The silk-screened text clearly delineate the brand and the inputs. I couldn't help but notice that some of the text was ever the least bit crooked, but I'm told that the next batches will have better control over the quality and precision of the lettering. Everything else does feel secure and well put together. Each unit is hand-marked with a serial number in the back for parts and quality control.
 
 
The front of the T1 is as minimal as it gets --- one input and one output, segregated by a single, bright blue LED. Numerous people with the T1 have noted how bright this LED is, and my goodness, is it bright! The charge indicator LED in the back is also equally bright, but because the color is red, it feels less piercing than the blue of the front power LED.
 
Charging is simple through the mini-USB port. It'd be nice to have a DC input as well, but thankfully, because of the excellent battery life (over 20 hours on one charge that takes about five hours, but I haven't needed to charge it ever since I received it), I can't imagine that you'd need to charge it too often. There's a charge indicator, as well as overcharge protection. All in all, operation doesn't get any simpler: turn it on, plug in your source and headphones, and when the battery charge gets low, re-charge via USB.
 
 
I don't know much about the architecture of the T1, but I do know that it sounds very nice, and it's surely one of the better values at its price point. Clarity is very, very good; everything sounds crisp and detailed, without sounding "digital". It also does a great job with vocals, too, with great centering and isolation, while not ignoring instrumental dynamics, either. It's quite transparent, but not without emotion. There's a slight undertone of warmth that bathes everything, but the T1 still maintains clarity. I don't personally have the numbers, but people I trust say that the T1 measures very well, and I can definitely believe that. It simply sounds great. I do notice minor hissing with a sensitive earphone such as my 4.A, but it is negligible (unless at volumes that no one listens at). There's also a distinct ON/OFF "pop" sound, though in general, I never plug in my stuff before I turn on the amplifier itself. Driving loads seems to be a complete non-issue for the T1; I didn't run into any problems with it, not even with the Sennheiser HD650.
 
Basically, I have zero complaints with the sound, it does what is advertised, and I repeat: it sounds great. In fact, if I could help it, it'd be my personal preferred sound for an amplifier. However, what I do have a problem with is the fixed 3x gain and the small usable volume range; with sensitive IEMs, such as my 4.A, it was way too loud to use for more than 15 minutes at a time at the minimum volume past the expected L/R imbalance of the volume pot (around 7:30-8:00). Even the RE-262 plays at the upper end of acceptable room listening volumes. Given that Tralucent Audio primarily manufactures IEM-related products, I would say that the gain level is definitely set a little too high. I simply cannot imagine using the T1 when it is fed from a line-level source, driving a twenty-something ohm, ~100 dB sensitivity earphone for more than 15-20 minutes, tops. I'd be very, very worried about the dangers of overexposure to noise otherwise.
 
I posed these concerns to Gavin of Tralucent Audio. He told me that the T1's primary purpose was supposed to be a direct booster to a variable output source such as the iBasso DX100, and that they tried to implement a gain switch on the T1, but believed it degraded the sound. Certainly, that's fair, but I think about all the people who use fixed output devices, including the many iPod users with LOD cables, and I would be concerned that if any of them are using the T1 to drive sensitive earphones or headphones, they'd simply not get enough usable play on their volume knob. I was personally working with about a half hour of twist on the pot, which is unacceptable in my view.
 
Luckily, I was also told that they were working on a revised version of the T1 with some critical changes, to both usage and cosmetic concerns, including a better volume pot with less volume imbalance issues, a less bright LED, and better durability. I’ve asked him also to entertain the possibility of a lower output version of the T1. As it stands, however, I find it difficult to find use of this amplifier with anything other than high-impedance, full-sized headphones (of which it has zero problems driving), and the hardest-to-drive insert earphones like the ER4S/B, Heir Audio Tzar 350, and the RE-262.
 
In the end, I can only state that I love the sound of the T1, but it plays at volumes that I just can't accept. I am really hoping that Tralucent comes out with a low-output version of the T1. Fingers crossed.
 
Additional Photos:
 
 
 
 
 
Feb 2, 2013 at 6:35 AM Post #4 of 17
 ​
Comparisons
 
Packaging & Accessories
Since the T1 was a loaner from Tralucent, I didn’t receive the T1 as it was packaged in its retail form. However, in its retail form, it does come with a number of accessories, such as an interconnect, USB charging cable, rubber feet, and securing bands. The Firestone is similar in its included accessories, but doesn't include any securing bands. The main difference between the HD and the T1 is that, while Firestone merely includes a tiny, cheap interconnect, Tralucent includes a robust, high-quality interconnect that looks like it’d outlast a hundred years of abuse. Most users will probably opt for their own interconnect anyways, so it’s not really a problem that Firestone only included a dinky little IC, but Tralucent goes the extra mile to include a nice, thick IC for the customer.
 
Build & Ergonomics
The LED lights on both units are bright, but the T1 is much more offensive in this regard, and unfortunately, while the HD’s LED is located in the back of the unit and utilizes a diffuser on its lens, the T1 projects its energetic blue light right onto your face at the front of the unit. There are also some small quality issues with the silk-screening on the T1; while hardly anything major to carp about, the text on the T1 is slightly crooked in a number of places, and doesn't quite have the crisp, high-quality definition of the lettering on the Fireye HD. Battery life is not exactly great with the Fireye at about 5 hours, but the battery life is great with the T1. If the Fireye HD is to be used consistently as a portable device, it'll need to be charged everyday, while the T1 only needs to be charged every so often.
 
Sound
The comparison is very simple, actually; both amps are very technically capable, and have strengths in different areas. The Fireye HD is ultra-fast and preserves details like no other portable amp that I’ve ever heard. The only real knock on it is that it’s so flat, it borders on boring. It’s a good thing I like boring! The Tralucent T1, on the other hand, is a more “forward” sounding amplifier. Both amplifiers are quite transparent; the T1 has a slightly thicker note presentation, and from a superficial perspective, I prefer the sound of the T1. Its particular coloration is very pleasant --- it lends much more emotion to the vocals, and has great center focus, with a pleasing rendering of reverb. It also gives listeners a sense of visceral power coming from their headphones by rendering both clarity and body convincingly. However, there’s no denying that the Fireye HD has better detail preservation. It might not sound as impressive at the outset, but it paints a wider, taller stereo image, and resolves with a refined delicacy that is remarkable in portable amplifiers. Separation in image depth is markedly superior. The T1 is still very impressive, however. I'd be very, very happy with the sound of the T1 --- it's only under the scrutiny of comparing the two that I feel the HD is a better amplifier. The T1 is a better damping match for low-impedance headphones/IEMs with its sub-1 ohm output impedance, but plays way too loud for sensitive IEMs at a fixed gain of 3. The Fireye HD has the opposite problem. The low-gain mode of 1.5x is good for sensitive earphones, but the 10 ohm output impedance makes it a very poor match for multi-BA IEMs. Both do very well with driving loads; nothing seems to rattle either unit.
 
Both units are good devices; unfortuately, each amplifier comes with its own set of caveats as well. I believe that, if there were a lower output version of the Tralucent T1, I'd tip the scales firmly in its favor, but right now, I can't decide. Both units have these little niggles that I can't live with, and its unfortunate, considering how nice both amplifiers sound.
 

Tralucent Audio T1
 
PROS
  1. Engaging, Transparent Sound
  2. Low Output Impedance Good for Most Headphones/IEMs
  3. Good Driving Power
  4. Great Battery Life
  5. Lightweight, Small Size
 
CONS
  1. Gain of 3x is Too High for Sensitive IEMs and/or Fixed Outputs
  2. Overly Bright LED
  3. Loud ON/OFF "Pop"
 
Firestone Audio Fireye HD
 
PROS
  1. Beautiful Fit and Finish
  2. Effortless Driving Power
  3. Very Neutral Sound, Wideband Presentation, Ultra-Fast Sense of Speed
  4. Selectable Gain (1.5/5) and Bass Boost
  5. Very soft ON/OFF "Pop"
 
CONS
  1. Output Impedance of 10Ω Not Suitable for Low-Impedance Headphones/IEMs
  2. Below Average Battery Life (5 hrs. Continuous Operation), Never Completely "OFF"
  3. Cheap Included Interconnect
 
 
Feb 2, 2013 at 6:50 AM Post #7 of 17
Quote:
I have the Fireye HD and although i have only had a brief play around i am not too impressed... these impressions may change of course but that is how i currently feel.

 
I disagree. Vocals sound flatter with the Fireye HD, but that's because it's very neutral. You're not supposed too use low-impedance BA IEMs with it because of its 10 ohm OI (due to the TPA6120 circuitry). With the right headphone, it's actually a more capable amplifier than the very impressive Tralucent T1.
 
Review for the Fireye HD is up.
 
Feb 2, 2013 at 6:55 AM Post #8 of 17
do not worry i am not saying your wrong for liking it or anything. I have not tried it with much either. In fact i only have used it with one BA IEMs, 4.Ai (and i personally preferred a few other), for a brief time. I have been busy with other things like a new dual dynamic i have and my HE-500 (which as you may guess it was atrocious with). I am not giving up with it here so do not worry but that is just how i felt so far.
 
Oh and will read the review now!
 
Feb 2, 2013 at 6:59 AM Post #9 of 17
Quote:
do not worry i am not saying your wrong for liking it or anything. I have not tried it with much either. In fact i only have used it with one BA IEMs, 4.Ai (and i personally preferred a few other), for a brief time. I have been busy with other things like a new dual dynamic i have and my HE-500 (which as you may guess it was atrocious with). I am not giving up with it here so do not worry but that is just how i felt so far.
 
Oh and will read the review now!

 
The 4.Ai will be a bad match for the Fireye HD. The inverted polarity of the TWFK means that the "dip" will get wider with increased electrical damping. Try it with something high impedance, and you'll hear its true ability. The one big flaw of the Fireye HD is that it's unsuitable for low-impedance BA IEMs. It sounds great with my RE-262, though.
 
Feb 2, 2013 at 7:39 AM Post #10 of 17
yes it was horrendous ahahah :p how about my MyST Nail 2 V2. Single BA - 120 OHMS impedance? :wink: Giving that a go now! Sounds so much better out of the headphone out of the MySt 1866, thats for sure.
 
Yes i knew this and thats why i got confused with it not doing well with the HE-500... But then they are not high impedance just power hungry so that may explain why!
 
Feb 2, 2013 at 7:55 AM Post #11 of 17
The Nail V2 will probably work better.
 
Orthodynamics work a little differently from BAs or dynamics. Reactance is very low on planar magnetic circuits, but resistance is very high. It requires high voltage swings to move.
 
I'm no expert, but the TPA6120 should work with high voltage swings with no problem. I did test the Fireye HD with an HD650 and there was zero problem driving it.
 
What leads you to say that it doesn't go well with the HE-500? Like I said, Firestone likes a very flat sound; perhaps you just don't like the way it sounds? I prefer the "sound" of the Tralucent T1 to the Fireye HD, but I believe the HD is a better amplifier.
 
Feb 2, 2013 at 3:19 PM Post #13 of 17
In the end, I can only state that I love the sound of the T1, but it plays at volumes that I just can't accept. I am really hoping that Tralucent comes out with a low-output version of the T1. Fingers crossed.   Nice review Tom, and I agree with the SQ description and the volume concern is accurate.   I actually use the ear out on my Studio V cause I think it sounds better than bypassing the amp out, and with my 7550 at 108sens my V is at 8 to 9 with the T1 halfway up.   I can imagine when my AS2 comes in with 123sens that my volume will go from 8 or 9 to 4,5 or 6!!!   Wonder if others with sensitive IEMS could comment???  My experience with Gavin is that he is awesome to work with and will certainly deal with this issue.   Yes the light is bright, but not an issue for me unless I point it at my eyes, LOL!!
 
 
May 7, 2013 at 8:14 AM Post #15 of 17
Quote:
  Hi, I'm using a pair of UM miracles and im deciding between these 2 amps. Which amp in your opinion is more suitable and why? thx :)


For the Miracles, it's likely the T1, as the high drivers for the Miracles will have bandwidth issues with the increased OI of the Fireye HD. If you don't mind the highs sounding a little strange, then you can consider the Fireye HD, but otherwise, the T1 is said to be undergoing revisions for a better volume pot and other case revisions. If these two are your candidates, then I suggest you contact Tralucent. I still think the T1 runs too loud for IEM purposes, but perhaps the better volume pot will help in that regard. The Fireye HD is more of an amplifier for dynamic driver headphones/IEMs, or, depending on the model, for single BA IEMs.
 

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