TouchMyApps » Firestone All Things iPhone and iPad for those who like to Touch. iOS App reviews, News, New Apps, Price Drops and App Gone Free Wed, 03 Feb 2016 17:15:54 +0000 en-US hourly 1 Firestone Audio Rubby and Libby in Review Thu, 21 Oct 2010 03:01:03 +0000 Firestone Audio have been making steady strides in desktop audio. To complement this year’s long, hot summer, they pushed out two hot amps: the Rubby power amp and the Libby headphone amplifier. Why they are such big news here at TMA is that both mains-powered amps also feature great USB/Optical/Coax and analogue audio inputs. If … Read more]]>

Firestone Audio have been making steady strides in desktop audio. To complement this year’s long, hot summer, they pushed out two hot amps: the Rubby power amp and the Libby headphone amplifier. Why they are such big news here at TMA is that both mains-powered amps also feature great USB/Optical/Coax and analogue audio inputs. If you can put two and two together, you’ve probably figured out that this means hi-res audio from the iPad through the Camera Connection Kit (CCK). Recently, I`ve forgone the whole computer thing in favour of just this combination. Still, both amps work great with computers, with external DAC`s, and with other Hifi gear. Nevertheless, TMA will keep the iPad slant in this review, but show just what can be done with these two desktop amps.

Build and Package
It has always been hard to fault Firestone Audio`s build quality. Generally, they package their products in high quality aluminium chassises, that if needs be, can be opened quite easily. Both the Rubby and Libby share the same heritage. Now, I don’t suggest grinding into Firestone`s amps with your favourite screw driver kit; you’ve got a two-year guarantee from Firestone, so if anything goes wrong, take your amp back to the dealer or ship it to them; everything`ll be as right as rain in no time.

And there is no way that either amp will be damaged in shipping as both amps come in rather bullet-proof packaging. They pack everything in hard pressure foam (if you order both at a time) and good ol’ fashioned styrofoam for the rest.

The Rubby comes with a pretty beefy power supply that will adapt from 100-240V and travel easily around the world with you. The Libby, on the other hand, transforms in-body and is available at only one voltage rating at a time. Planning on moving from Sweden to Canada anytime soon? You’ll have to get a new step-down external transformer. Firestone could have powered their unit from an external unit, or include a switching supply inside which would make moving a lot easier. I don`t know if the Libby`s background noise (read on) is a result of the power supply or not.

What they didn’t mistake is front-panel ergonomics. Their accessibility especially with regards to volume pots only seems to get better every iteration. The Rubby and Libby volume pots are as fun to play with as the amps are to listen to! Inputs and frequencies are selected on both amps via the front panel. If you have an iPad and a Camera Connection Kit, you’ll only be concerned about 16-bit USB input, and if you have a DDS i2s machine handy, 24-bit USB input. Bpth amps upconvert the signals, so the actual thumbing-around that you`ll need to do is very light.

Back-panel inputs are well thought-out, especially on the Rubby, which follows a logical switch array from power to analogue input. Both amps can be switched on blindly, but the Rubby’s nubby flip switch, which sticks out from the rear left like a proud nose, requires no reach-around. The Libby headphone amp is switched on a little less comfortably: you have to finger-walk past the IEC power cable to the on switch. It is a small complaint, but one that makes me wonder firstly why the two amps, that look so much alike, couldn’t have shared the same great ergonomics and external power supplies.

The other puzzling thing about Firestone’s amps is one of outputs. The Libby Headphone amp sports a decent analogue output, but the Rubby doesn’t. Typically, the power amp is the staple equipment in a lot of audio setups. Without an analogue or digital output of any sort, it can’t be used with Firestone’s own analogue headphone amplifiers, unless, that is, you bypass the Rubby power amp. This decision is downright naughty if you ask me. Right, the headphone amp, Libby, has an analogue output that connects nicely to the Rubby, but the logic seems backward, unless Firestone intend both amps as 100% stand-alone desktop systems.

Both Libby and Rubby (cute names, eh?) can take in analogue signals from RCA or XLR to power your speakers or headphones of choice. But, their mainstay components are their DAC chips. From coaxial, to optical, to USB, they’ve got their bases covered in both 16 and 24-bit word lengths. Only the Libby headphone amp is class-A biased, meaning that theoretically, it sounds better (and gets hotter). NOTE: USB is only good for 16-bit and up to 48kHz, strange since USB can easily handle 24-bit word lengths up to 96kHz (if you have a Mac).

Each bit and frequency setting is finger-selectable from the front panel, and after a lot of thumbing around, I’ve discovered that no matter the word-length of the original source, music will travel to your speaker of choice without hitch. Kudos for newbie music lovers as audio stuff can get tricky.

Mac users, you can connect USB or optical with no hitches. Windows users, you should be able to get buy with USB, though if you want to head up to 96K 24-bit, you may have to jump through a few hoops. The great thing is that both amps can be connected directly to the iPad via the Camera Connection Kit. Till now, we had to rely on iDevice-only DAC converters that had less value than either the Libby or Rubby. Now, thanks to Apple’s foresight, we’ve got way to connect our favourite music/movie/gaming devices to high end gear. Not to mention, the iPad’s understated grey looks great next to either equally understated Firestone amps.

I can’t stress how cool this is. I’ve used dedicated headphone amps before, and DAC’s, but the latter always get stuck in home systems or fed from computers. Now, plug the white nubby Camera Connection Kit into the end of your iPad, feed a USB cable to it, and you’re off. There is nothing simpler than taking your iPad and its CCK to a mate’s to play high-quality music. Now, the iPad’s USB out isn’t a full-fledged USB, making mains or battery-powered amps necessary. Of course, Rubby and Libby play fine.

Both amps sound purty, too, especially as they are liable to be targeted to desktop users who use headphones or sensitive speakers. Typical Firestone, both are high-resolution devices with good emphasis on all frequencies. That said, Firestone’s Libby and Rubby (yes, they share very similar output tendencies), aim for what I will call gritty sonics.

Both output powerful bass lines, enough to Hulk-smash bass weak headphones. It’s not, however, duffy, smooth bass. Both Rubby and Libby shoulder their way around low notes. They are clean and highly defined with slight bumps in the frequencies with sensitive headphones or speakers. While I carried the Rubby from speaker to speaker at local shops, the Libby got off well with my 64Ω Ultrasone DJ1Pro, but ultimately much better with my excellent 600Ω Beyerdynamic DT880 headphones.

The latter pairing is one of power and control. Even with the 600Ω monster, a turn to about 10:30 on the volume pot was more than enough for most music. 12:00 is right out of the equation with any headphone. Both amps` volume pots accelerate like teenage hormones to dangerous levels at the smallest of turns.

I found this funny and tested it by lowering the output of various sources. The volume pot is well-balanced, showing just slight variance between left and right, but after about 12 o’clock on the volume pot, volume increases slowly and distortion can creep in, though only mildly. Firestone should re-think their design and add a LOT more play in their volume pots. Now, if their amps are aimed at new-to-hifi users, this immediate ‘wow’ factor may impress its clientele who can value volume more than overall usability. But I say: more play in the volume pot would allow for easier left-right tuning, and less chance of accidentally blowing your speakers or headphones.

That is all to say that these amps output a LOT of power. The Rubby is certainly enough to power larger, less sensitive speakers, but I think its best target is the desktop where its boxy, powerful sound will give smaller speakers extra oomph.

I really appreciate Firestone’s emphasis on stereo image. Both amps supply wide separation in channels. The Libby is very much like a more powerful Fubar IV. Both amps brute-force their way around any headphone. At the bottom of the chassis, you can select the best output for your headphones, from 32Ω to 250Ω. Don’t let those numbers fool you though, as there is nothing wrong with hooking up a 600Ω load to the Libby: it’s got the power to blow up the DT880 600Ω.

Where it (and the Fubar IV) somewhat fail is when driving sensitive headphones. They drive them fine and output negligible distortion, but the signal can be hairy. Sensitive headphones from Grado to Ultrasone can reveal background noise. It’s not inordinate; rather, the fine grain dusts everything.  Anything over 120Ω reveals nothing but the blackest of black signals. Again, I see this amp used a LOT with 300-600Ω headphones where its power and brute force resolution are often-requested items.

The Rubby, however, has no such problem with noise. It was suggested that the Fubar IV could be upgraded by given a better power supply. Since it was outboard, it was a lot easier to do. The Libby has an on-board power supply which is kind of a bugger. Of course, it could just be a problem with the audio circuit amps such as the Woo Audio 3 and Einar Sound VC01i have better-behaved noise patterns.

So, while I would like to rave about both amps, I find enough to cringe over regardin the Libby. It is a fine amp, but it may need an internal makeover to lessen the noise, and an external makeover to conserve eardrums thanks to an over-active volume pot. Oddly enough, the Rubby power amp has no such issues with background noise and sounds great with sensitive speakers.

Both units hit positive price points: these are powerful amps coupled to excellent DAC’s, combinations that often cost much more. Neither USB input supports more than 44.1 16-bit audio, but their other inputs supply at least 96K and 24-bit word length. The Rubby comes away feeling like a more polished amp, but thanks to the lack of an analogue output, unfinished.

The Libby, as powerful as it is, has some unfortunate design decisions attached to it, namely the too-powerful volume pot and the constant grain that covers almost all sensitive headphones.

Firestone continue to hammer away at great price points. Both the Rubby and Libby perform in general terms above my expectations for their price and feature set, and I feel, are good investments. The Rubby is an impressive piece of for desktop audio and the Libby, more impressive from a feature standpoint, comes away as a less thought-out piece of equipment.

Firestone: add analogue/digital output to the Rubby and you’ll have a power amp/DAC that features in home systems, not just desktop systems. Do that and you’ll have a perfect KISS. The Libby needs an outboard power supply, a rethinking of the volume pot, and less noise in the signal. When you can do that, you’ll see a GRAB or a KISS.


DAC-Firestone-RubbyLibby-back-1 DAC-Firestone-RubbyLibby-backr-1 DAC-Firestone-RubbyLibby-glamour-1 DAC-Firestone-RubbyLibby-glamour-lights DAC-Firestone-RubbyLibby-ipadRead more]]> 0
Firestone Fubar IV headphone amp/DAC in Review – effin’ good! Thu, 17 Dec 2009 09:39:54 +0000 Firestone have hammered the last studs into their newest audio block just in time for Christmas. The Fubar IV headphone amp/DAC continues the tradition of excellent price/performance for which Firestone are famous and even enjoys a price reduction from last year’s model. This amp sports USB input which makes enjoying high quality music from your … Read more]]>


Firestone have hammered the last studs into their newest audio block just in time for Christmas. The Fubar IV headphone amp/DAC continues the tradition of excellent price/performance for which Firestone are famous and even enjoys a price reduction from last year’s model. This amp sports USB input which makes enjoying high quality music from your computer a breeze and in the same breath, hooks up to SPDIF and digital coaxial input for direct lossless listening from HiFi sources. Finally, it has also wormed its way into my heart with its excellent pre-amp and even-Stephen sound.


  • Amplifier Structure : Coupling capacitor less, Push-Pull with Class-B
  • Linear Output : RCA output 2Vrms, delay time phone out funtion
  • Power Structure : Switching power supply, Soft-Star circuit
  • Gain Control : Low (attenuation 20dB) / High (normal)
  • Volume Control : Series / shunt mode selectable
  • Headphone Impedence : 32 ohm to 600 ohm
  • Circuit Protect : Output short / over current protect
  • Support Format : 16-bit, 32 / 44.1kHz / 48kHz
  • USB Chip : CMedia – CM108
  • Receiver Chip : TI – DIR9001
  • DAC Chip : TI – PCM1754
  • LPF OPAmp : TI – OPA2134
  • Main OPAmp : TI – OPA2604
  • Servo OPAmp : TI – TL072

Build and Packaging
Im typical Firestone fashion, the Fubar IV comes in a strong extruded aluminium chassis which is bolted together into a veritable brick of audio goodness. The amp’s front panel has a single full-size female phono jack and a large analogue volume pot which bares nary more than the Spartan volume indications: + and -. Power is engaged on the rear panel via a horizontal toggle which is a bugger to get at especially when operating in either optical or USB mode. Ergonomic issues aside, the army of audio input and output on the rear panel is spaced just well enough to remain under the radar of annoyance when the amp requires to be moved and unplugged. The Fubar IV is roughly the same size as the Travagan’s Red, so the biggest barrier to perfect ergonomics isn’t the number of connections, it is the size of the amp.

Its volume pot rotates with the slightest of mechanical grinding, but has lots to love; you cannot help but stare no matter how politely you try to ignore it – it is huge. Inside the box is one 1,5 metre USB cable and a fatter-than-Monster RCA to RCA audio cable. Firestone skimped on the power supply, but not much else. The entire package is housed in a cute “Merry Christmas” branded cardboard box. And if you have good eyes, you will find a tiny allen key which after a few grunted twists, will open the Fubar IV up for op-amp swapping.


The Fubar IV really tries to compete in the growing niche of do-it-all audio products. Audio input comes in 3 digital flavours: USB, Coaxial, and Optical SPDIF. Its preamp section passes the message on from sturdy analogue RCA outputs. So how well does it work? Speaking for the pre-amp, outboard connection to other audio equipment is really a table of spades including quality signal which bests thtravae headphone out.


While the Fubar IV features a no-hassle USB input, I generally used the excellent SPDIF optical input. What isn’t advertised in the Fubar’s spec list is that it can also drive low ohm earphones. The spec sheet shows 32-600 ohm, but it easily drives a great frequency response down to balanced sensitive armature earphones which cause many home amps to squeal in pain. Mind you, listening to the Fubar IV through earphones isn’t optimal – we will see this later.

The two gain modes: high and low, work well for a large variety of headphones. When listening to the 600 ohm DT880 in high gain mode, I set the volume to a comfortable 9 o’clock, and to about 12 – 1 o’clock when in low gain mode. And if you’ve had enough with the stock sound signature, the Fubar IV can be disassembled for op-amp swapping.


Audio Performance
There isn’t much to decry. Firstly, even with low ohm headphones, balance is very good at low volumes. On low gain, volume hungry headphone like the 600 ohm DT-800 will reach uncomfortable levels when the volume knob is turned much past 50%. Toward 100%, it will be too much. But, at extremely loud volumes, the Fubar IV distorts heavily past 3 o’clock on the volume pot, leaving the last 30% of the signal a messy affair. Coincidentally, the same is true for the Travagan’s Red which was built by former Firestone engineer, David Lin.

Where the Fubar IV trumps the Red; let me rephrase that: where the Fubar IV smacks the Red around with a frozen fish is in its unadvertised low ohm headphone output. The Red can drive a reasonable signal into 32 ohms, but when faced with balanced armature earphones, it dies in its tracks, losing its otherwise pristine frequency response. The Fubar IV on the other hand, handles the odd impedance swings of balanced armature headphones very well, providing full bass and low distortion even with the hard-to-drive FitEar Private 333. The only casualty is some treble roll off, but then again, who listens to mains-powered headphone amps with inner earphones anyway?

HP-Amp-FubarIV-FE333-optvsusfr HP-Amp-FubarIV-FE333-optvsusb-ct

That point leads to the Fubar IV’s biggest output problem. While it sustains pristine response, and as I will venture to praise later, smashing bass, its headphone output is noisy. Even my DJ1Pro can detect a small amount of background noise in one channel regardless of input method. The DT880 of course, is free from hiss at all but the highest of source/amp volume settings. Earphones are another story. Each hisses like an orgy of angry grandmothers, but thankfully, the Fubar IV everything else well.

HP-Amp-FubarIV-dt880-optvsus-fr.jpg HP-Amp-FubarIV-dt880-optvsusb-CT.jpg

Let’s drop literal explanations from here on out. This amp sounds good. It has a strong signal, great frequency response, and if I were to apply an adjective to it, it would be something like: square, but that word is often construed negatively. In my terms, ‘square’ means full, resolved, and well-shouldered. It hits the low notes great, rumbling both little and big headphones very well. And, it is full of solid, dry PRaT which errs on neutral side of foot-tapping. Both the Red and the IV sound very good in their price ranges, but the Fubar rolls a drier, stodgier fag between its teeth and puffs a signal which would satisfy a trucker.

Vocal genres maintain throaty resonance, soundtracks smashing stage, and guitars wonderful speed and space. But balance, neutality, and PRaT take precedence over finesse. Cymbals lack a bit of magic sheen, and female vocals that last smidgeon of saliva which flows on spiky treble/mids. Guitars, pianos, strings: natural instruments carry great body and texture. It carries the traditional solid-state signature well, but leaves a bit of beef between headphone speakers for a thick, satisfying sound which has no glaring faults or glorious strengths.

Chart Disclaimer
This review’s RMAA measurements reflect the performance of the Fubar IV when fed optical signal from an Edirol FA-66, and USB from a MacBook Pro. RMAA tests, however, only tell one side of the story: signal quality. They don’t relinquish the finer details: those bits which tickle the ear, which make you blink and go, ‘wow’! These results are applicable to my equipment only and should be used as a reference for general sound quality, not a definitive answer.

Audio Conclusion
The Fubar IV is a massive upgrade to any computer headphone output, and will be a good investment for optical-toting HiFi systems. Another even-Stephen performer, it does bass, mids and treble powerfully, if erring on the side of neutral. It also passes on a pristine signal to external audio equipment. But no matter how well it performs, it isn’t a great mains amp to pair with earphones of any type; more specifically, if hiss concerns you, stay away with highly sensitive headphones. Apart from that, volume is well-balanced and the gain system works well.

But Firestone have to clean up two issues. Firstly, the ON/OFF switch pops loudly when disengaged. I have owned and used many amps at various price points and among all of them, the Fubar IV is the most annoying. I would suggest to keep your headphones unplugged whilst engaging/disengaging its power. And considering the smashing performance for headphones from less than 16 ohms to 600, it is too bad that the amp hisses as much as it does with earphones because its sonic qualities aside from that, are excellent.


Firestone’s sights are set reasonably high. This 220$ amp/pre-amp/DAC combo does most of what I would expect from a much more expensive piece of equipment and it does it well. Many ‘DAC’ toting amps boast USB input, but little else. The Fubar IV manages to squeeze in SPDIF and digital coaxial as well. It also sounds good, so long as your headphones aren’t hiss-prone. It does very well with all of my headphones, providing flat, strong signal in all frequencies, and great space and breath. If Firestone would fix the mains ‘pop’ and the unit’s hiss with low-ohm headphones, they would have a killer audio unit.

Till then, though, this all-in-one will have to settle for a GRAB.


Amp Summary
Title: Fubar IV Headphone amp/DAC Developer: Firestone Audio
Price: $222 Amp Size:
  • Great packaging
  • Good sound
  • Input array is impressive
  • Can drive a lot of headphones
  • Good pre-amp functionality
  • ON/OFF pop is annoying
  • Hiss with sensitive headphones, even DJ1Pro

Headphone amps and DACs help your headphones get the most out of their transducers. Take a look through our headphone section for suggestions of good upgrade/sidegrade options, and our headphone amplifier section for suggestions on how to wring out the best performance from your beloved phones.

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Fireye II USB/DAC headphone amp in Review – Full Metal amp Fri, 16 Oct 2009 09:25:38 +0000 In a follow-up to last month’s review of the Fireye I headphone amplifier review, TMA will continue our look at Firestone products with the unique Fireye II USB/DAC headphone amplifier. Unlike the Fireye I, this unit does not accept analogue inputs and it is not a stand-alone amp; it functions 100% from USB ports as … Read more]]>


In a follow-up to last month’s review of the Fireye I headphone amplifier review, TMA will continue our look at Firestone products with the unique Fireye II USB/DAC headphone amplifier. Unlike the Fireye I, this unit does not accept analogue inputs and it is not a stand-alone amp; it functions 100% from USB ports as a plug and play audio device, and thankfully has a manual volume pot for volume attenuation. Its specific function is to create a clean audio signal for headphone listening from a computer, a job which it does quite well.

Amplifier Structure: Class A/B
Power Structure: USB or Optional 5VDC external power supply (available separately)
Headphone Impedance: 32 – 600 Ohms
Circuit Protection: Short circuit and temperature protection
Support Format: 16-bit, 32 / 44.1 kHz/ 48 kHz
USB Chip: CMedia – CM 108
DAC Chip: Cirrus – CS4344
Main OpAmp: TI – DRV601

Build and Packaging
The Fireye II comes as solidly built as its sibling, and as such, is a among the most well-made in its price class. Its heavy aluminium casing serves two purposes: to protect its innards, and shield the unit from radio interference. It comes with the same accessories and great cardboard box as the Fireye I.

There are a few visual differences between the two amps which are dictated by their respective uses. Unlike the Fireye I’s charging circuit, the Fireye II’s rear-mounted USB port interfaces with a computer to provide analogue signal to headphones. The front panel houses the same on/off lamp as seen on the Fireye I, but layout similarities end there. Unfortunately, the headphone output port took a step back in build quality from the sturdy metal port of the previous amp – it is now plastic. However, it keeps up with the family by installing only one contact per pole. The toothed horizontal volume pot is next to it and on the rear panel is an impressively busy affair which is packed by the following: a 5V input, power selector, and USB port.

It remains as easy to open as the Fireye 1, requiring only a small philips screwdriver and opposable thumbs. And it not only looks solid: it is. Dropping this badboy to the floor will result in broken tiles, dented wood, etc.; the Fireye II is a very solidly constructed piece of audio equipment. Even so, it comes in well-designed, well-padded, and compact cardboard box. Inside, the amp, pseudo felt bag, connection cable, and USB charging cable are packed neatly in soft, protective sponge foam. Not that anything would really damage the amp. The ‘felt’ bag is a good accessory, however, as it keeps the amp from suffering small scratches, or more feasibly, from gouging your computer or desk!

Again, for the price, there is little to complain about – it, not you, will survive the coming wars.


Features in Review
First and foremost, the Fireye II is a USB/DAC headphone amplifier. While it does not function apart from a computer, it is a much more competent amp than its simple signal booster sibling: the Fireye I. Firstly, the volume pot is a much-needed addition to any amp simply because allows your music to maintain a higher signal-to-noise ratio.

It still hisses with sensitive headphones, but not as much as its sibling, and much, much less than a computer’s audio output. Since its amp circuitry comes from internal digital conversion (a much cleaner process), it is a much cleaner, better source than a laptop or desktop. You can power the unit completely via USB, or when your headphones need a little more power, the unit can also be plugged into the mains.

A great feature which doesn’t get enough press is the ability to pass on a 16bit optical signal to an external DAC, computer, MD, hi fi, etc.. If your computer lacks optical output, the Fireye II is a good pass-through for digital components, effectively rendering your computer into a hifi component.

MBP VS FEII Optical-fr MBP VS FEII Optical-ct

It is completely plug and play: merely connect it via USB and select it in your computer’s software or control panel settings and, voila! instant sound upgrade. On my Mac, it shows up as a C-Media sound card, which incidentally, is the same circuit which inside of the Nuforce Icon Mobile.

Audio Performance
Amplifying headphones won’t reveal as stark a difference in sound as upgrading them to better models. However, there are certain, universal differences which nearly all amplifiers exhibit when compared to un-amped sources. Low frequency signal integrity usually degrades horribly when driven from “naked” audio sources such as sound cards, and especially, portable audio players. Similarly, hiss levels and distortion skyrocket from computer audio output. The Fireye II does a good job of reducing/eliminating these artifacts, but it isn’t perfect.

Like its sibling, the Fireye II isn’t among the most itchily-detailed amps out there, however, the FEII will reward those who enjoy crisp mids and highs and a decently weighty bottom. No frequency belts out in exemplary tones, but for the price, this amp should be a great companion to many headphones.

Depending on the headphone you use, the FEII will perform differently. Most headphones sound good when paired with this amp, however, some ‘mate’ better than others. Very sensitive inner ear monitors (IEMs) reveal hiss, but not too much. Generally, bass performance does not fall off, and even with the difficult-to-drive 16 ohm Kenwood C700 torture test, frequency response remains respectable. But, in direct comparison to the MBP headphone output, the FEII has much less hiss, whine, and audible distortion than when powered from the headphone out of a computer.


When moving up in price and down in sensitivity, the Fireye II really begins to strut. The 64 ohm Ultrasone DJ1Pro has no hiss at all with the Fireye II, and maintains a great frequency response from 20Hz to levels above 15KHz though there is a pronounced upper treble roll off. This headphone is detailed and speedy, but has great bass performance, and if anything, slightly laid back mids. But despite its ostensibly sterile market of DJ’s and studio engineers, it is a stunning listen for many genres and pairs well with the Fireye II. However, this headphone will reveal slight bass distortion from both the amp and the MacBook Pro’s headphone output. The latter, however, is at times, quite bad.


This trend is largely true for any headphone and a good point in favour of the amp: it simply stomps the mediocre headphone outputs of regular computers. But moving much further up the scale, to the excellent Jerry Harvey Audio JH13Pro, the FEII begins to hit a wall. Jerry Harvey’s masterpieces haven’t been properly driven from any external amp I have tried, including mains-powered modules – it is a very hard to drive headphone which will cause most normal to mid-end audio equipment to suffer huge bass roll off, and conversely, an uncanny upswing in treble amping. While the JH13Pro sounds good from every amp I have paired it with, its presentation remains unique and is likely a product of impaired amping.


For all other headphones, the Fireye II sounds better than any PC internal soundcard that I have tried, and also tests better under load than most of them. While not perfect, there is very little detail loss in any frequency with all but the most difficult to drive headphones. The Fireye II simply sounds better than most on-board computer headphone outputs, has a cleaner output, hisses less and suffers less distortion.

On a side note, it is a smashing match with a MacBook Pro!

MBP, Fireye II and JH13Pro - what a match!

MBP, Fireye II and JH13Pro - what a match!

Like many amps which utilise volume pots, the Fireye II has a few quirks, namely channel imbalance. At very low volumes, it will amplify one channel 3-5 decibels louder than another and to compensate, the computer’s software volume will have to be attenuated, the amp’s volume pot raised, and both monitored for balance. This presents little trouble for headphones like the DJ1Pro, but IEMs and earbuds are sorely affected. Even at a very low software volumes, finding the ‘right’ balance is hard simply because the volume put must be set to about 20% of its full output before balance is set aright. Conversely, at the top end of volume, there is little to no difference in output levels after the pot is set to about 60% volume. I have yet to use any volume pot equipped amp which does not suffer some imbalance, but this amp has it slightly worse than a few others I have tried.

That said, the pot itself is stiff enough to deflect accidental turning.


Chart Disclaimer
My findings are based on an Edirol FireWire Audio Capture FA-66, a very good, but not excellent audio capture card. It is made for musicians on a budget, but still manages a decent array of input options and apart from a horridly constructed headphone output,has very decent recording circuitry. For recording from analogue sources, I use the balanced 1/2 inputs in either TRS or XLR connections.

Your mileage may vary. These are soft, but wise words which should be observed when using any amp. As you can see, the easiest headphone for to drive is the 64 ohm DJ1Pro which allows both the Fireye II and the MacBook Pro a lot of breathing room, but out of the external DAC, it hisses less and overall, is more cohesive.

Sound Conclusion
The Fireye II is a much more impressive audio circuit than the Fireye I. It has a cleaner signal, a dedicated volume pot, and does a better job of cleanly ‘driving’ headphones. While it lacks the Fireye I’s bass jumper settings, it doesn’t need them — at least when amping most headphones — as its frequency response is largely laudable. When put through the torture test of the JH13Pro, however, it falls as hard as any current portable headphone amp I have auditioned. The good thing is that most of those amps cost more and are built by more famous audio houses. While the Fireye II DAC/amp does not deliver staggering stereo separation, or universally low distortion lows, it thumps the headphone output of most computers and is a good companion to most headphones. For movies, games, and music — assuming you don’t mind doing everything in stereo — it is a great, comparatively inexpensive option.

For 115$, you get an amp which should stand up to any cataclysm. From its sturdy extruded aluminium chassis to well-laid out array of ports, it is a well designed amp. Of course, it is meant to be paired with a computer, a job which it delivers in spades; just plug and play, and instantly, your sound is upgraded from a hissy and often chaotic background hum, to clean, well defined audio. The Fireye II also acts as an optical pass-through for pairing with a Hi-Fi or other optical equipment.

Again, for the price, it performs admirably, faltering at the same places where other, higher priced amps also misstep and exceeding expectation in other areas. Against its market, it is one of the better options, but it lacks some refinement. The volume pot for instance, has too much play and may frustrate users who want to listen with sensitive inner earphones as well as headphones.

All things considered, this is a TMA Grab.


App Summary
Title: Fireye II USB/DAC Headphone Amp Developer: Firestone Audio
Price: $115 MSRP
  • Non-lethal packaging
  • Great design, good looks
  • Good, detailed sound
  • Optical signal pass-through capability
  • Sturdy construction
  • Mains and USB power
  • Plug and Play
  • Price/performance/features
  • Quirky volume pot
  • Higher than average distortion and low signal to noise ratio

Headphone amps and DACs help your headphones get the most out of their transducers. Take a look through our headphone section for suggestions of good upgrade/sidegrade options, and our headphone amplifier section for suggestions on how to wring out the best performance from your beloved phones.
Fireye I Headphone amp in Review

MBP VS FEII C700-01 MBP VS FEII C700-02 MBP VS FEII DJ1Pro-02 MBP VS FEII DJ1Pro MBP VS FEII JH13Pro-02 MBP VS FEII JH13Pro MBP VS FEII Optical-ct MBP VS FEII Optical-fr Review-HPA-FSFEII-boardLogo Review-HPA-FSFEII-Box Review-HPA-FSFEII-DJ1Pro Review-HPA-FSFEII-tabletop MBP, Fireye II and JH13Pro - what a match!Read more]]> 4
Fireye 1 Portable Headphone Amp in Review – Heavy Metal Mon, 07 Sep 2009 07:08:16 +0000 Taiwan’s Firestone Audio is known for creating high-quality amplifier and digital-to-analogue products at reasonable prices. One of their constants is the use of sturdy construction materials and methods, a design decision which guarantees the longevity of their products. The Fireye 1 is an impressively constructed headphone amplifier which has a couple of unique features that … Read more]]>
Sitting pretty with Markuz Schulz and the iPt 2G

Sitting pretty with Markuz Schulz and the iPt 2G

Taiwan’s Firestone Audio is known for creating high-quality amplifier and digital-to-analogue products at reasonable prices. One of their constants is the use of sturdy construction materials and methods, a design decision which guarantees the longevity of their products. The Fireye 1 is an impressively constructed headphone amplifier which has a couple of unique features that will help you enjoy music and movies from your your iPod, laptop, or larger, hifi source.

Output – 150mW Stereo
Frequency response: 20Hz to 20,000Hz
Impedance: 16 ohms
Input – 3.5mm stereo headphone jack
Output – 3.5mm stereo headphone jack
Mini USB port (For charging)

Additional Features:
Pop Reduction Circuitry
Internal Mid-Rail Generation
Thermal and Short-Circuit Protection
Auto On with LED indicator
Metal housing protects against EMI and RFI interference
Power and Battery
Built-in rechargeable lithium Ion battery
Charging via computer USB
Fast-charge time: about 1.5 hours (charges up to 80% of battery capacity)
Full-charge time: about 3 hours
Music playback time: 
Up to 24 hours when fully charged

Build and Packaging
From the get-go, the Fireye 1 is a great device. While not pricey, it comes in a cute, but firm cardboard box which is compact and well-labelled and easy to open. Inside, the amp, pseudo felt bag, connection cable, and USB charging cable are packed neatly in soft, protective sponge foam. Not that anything would really damage the amp: the Fireye 1’s chassis is machined from a solid, heavy aluminium which can withstand heavy pressure from the outside. The ‘felt’ bag is a good accessory, however, as it keeps the amp from suffering small scratches, or more feasible, from gouging your iPod!


The amp’s package feels ‘complete’ and since the Fireye 1 has an internal battery, there is no need for fumbling with charging accessories or switching power sources. However, the Fireye 1 is easy to open. It is fastened by four screws, one in each corner, which when removed, give easy access to the circuit board which pulls out from a slotted vent which runs the length of the amp’s chassis. Replacing the battery should be duck soup (as long as you can obtain a replacement): simply grasp the plug firmly, pinch and pull like you would computer logic board connector. The battery rests on a slight sponge via adhesive, but anyone familiar with a spludger should be able to pry it up.


As for connection quality, the Fireye 1 is quite good, if not exemplary. In particular, the headphone out is a thick metal-ringed port which won’t likely snap or fold with pressure from the headphone jack. The input, however, is ringed by a plastic port which is less sturdy. Each connect via one contact per pole which is par for most manufacturers, but could benefit from the insurance which can be derived from extra contact points.


In a later review, TMA will cover the Nuforce Icon Mobile, a great portable from the makers of the excellent NE7M headset. While the amp stage is quite good on the Icon, it is less robustly built and suffers what an embarrassing setback: recessed connection jacks. Unless all of your connections are super slim, you won’t get a full stereo image. The Fireye 1 is free of these problems. Each connection jack is flush with the chassis body, or in the case of the headphone out, extended by about a half-millimetre.

Features in Review
The Fireye 1 is an amplifier that in the literal sense, amplifies the signal. However, it is closer to what in the headphone world has been dubbed a, ‘booster’. Most battery-driven headphone amplifiers come with attenuation circuitry to control music volume internally, but the Fireye merely boosts the signal from the source at a static level. This has both good and bad points. Firstly, it means that your ears are protected from sudden volume bursts which happen when the attenuator or volume pot might accidentally be nudged up, a common problem with portable amps. While from a certain perspective, this is helpful for portable application, it has a couple of drawbacks.

Firstly, it means that in order to raise or lower the volume, you must do it from your source device which is problematic. Whether computer, iPod, other DAP, DVD player, etc., your device is either already attenuated at a line-out level, or is internally amplified. In the case of the line-attenuated device, utilising the Fireye 1 is tricky because most headphones whether sensitive inner earphones or large, insensitive headphones will be too loud. Since the amp’s circuitry is static, there is no way to comfortably adjust volume levels without adding another circuit to the audio.

Secondly, it means that any noise in the source circuit will be amplified. Sources such as computers, the iPod Shuffle, many iRiver players and older iDevices have audible hiss when plugged into sensitive headphones. Because the Fireye 1’s volume is static, you must set the volume on your source to a comfortably low level which usually means that the noise of the source will only get worse. Headphone amps which feature volume pots or stepped attenuators allow you to set the source to its highest volume which will give it the best signal to noise ratio. Then, the external amplifier will do its job of reducing hiss and attenuating sound levels.

Battery life, as quoted is a long 24 hours which I have been able to replicate. Some amps get better battery life, and others worse. 24 hours is quite good and since a fast 1,5 hours will charge to 80% the Fireye 1 is never out of use for long. There isn’t an ON/OFF switch. Rather, activation is automatic upon the insertion of headphones and source cable and is indicated by the glow of a green light when the battery is healthy, and a reddish light when the battery needs more juice.

What Firestone don’t advertise is the special Left and Right bass boost settings. After removing the logic board from its chassis, bass levels can be adjusted by moving jumpers from default (OFF) to +2, creative a hardware equalisation circuit which helps bass anemic headphones. The effect will be discussed a little later.

Bass jumpers

Bass jumpers

Otherwise, the Fireye 1 works as advertised, but just how well is the question.

Audio Performance
Amplifying headphones won’t reveal stark differences as will ditching your iBuds in favour of a cheap MEELectronics or Nuforce headphone. However, there are certain, universal differences nearly all amplifiers exhibit when compared to unamped sources. One is low frequency signal strength which often degrades horribly when driven from a “naked” (iPod or other DAP without an amp) portable audio source. Another is increased channel separation for the completion of a strong stereo representation in music.

All amps are known for a certain sound ‘signature’. The Fireye 1 could be considered a smooth, rather relaxed amplifier which voices warm mids and lows, while slightly extending high frequencies. For lusty vocals and mood music, this amp is special, but for faster music which prefers resolution over mood, there are better optioins.

Performance will vary depending upon the headphones you use, but there are certain undeniable traits which the Fireye 1 exhibits.

The first is is relaxed low frequency presence. Unlike many portable amps, the Fireye 1’s output doesn’t bolster the weakly powered headphone amplifiers inside of iPods and other portable sources. In fact, when using sensitive earphones, bass output is less than when powered straight from man iPod touch 2G. This is not necessarily a bad thing, but it is unexpected. This loss of bass definition is termed ‘bass rolloff’ and is a common characteristic of many sources.

Certain genres benefit from relaxed, but full-bodied bass. One of these is American Hip Hop whose low-resolution bass lines can be jarring with too much edge and vibration. Of course, depending on mood, other genres such as jazz and vocal music can sound lovely when detail is turned down as it were.

When paired with the iPod touch 2G, there is a subjectively ‘stark’ difference when using the Fireye 1 and when not. The iPod touch is technically a very good sounding player which excels in electronic, classical, and rock genres, but which can comparatively suffer from unemotional playback. The Fireye 1 adds that emotion that the Touch may lack on one hand, and decreases edge and grit on the other.

For vocal music, the Fireye 1 is a great companion. Madeleine Peyroux’s Careless love sang with more melody and emotion than via the Touch 2G as did a number of similar artists. If your source is cold, the Fireye 1 may add a fuzzy blanket to the mix.

High frequencies aren’t incredibly emphasised, but in the bat-range, they take an upward swing of about 1-2db, giving certain music a slightly airy, detailed presentation. Instruments remain well separated even when driven by voltage-hungry low impedance inner earphones. However, Firestone’s amp doesn’t Despite this however, the Fireye 1 cannot ‘drive’ any headphone for any semblance of bass resolution. Simply put, no matter the sensitivity, no matter the impedance, there is audible loss of detail in bass. When setting the bass jumpers to ‘+’ settings, bass presence is increased at the expense of incurring some boom, but mids and highs in comparison, are reduced by about one decibel. Having used several amplifiers which feature selectable bass enhancers, I am impressed by the relatively fatigue-free change introduced by the Fireye 1′s bass jumpers.

Lastly, though certainly not least, is hiss. Firestone’s amp is not a deathly black. Its background is a constant sheen of white noise similar to a television which has lost its reception. Though not audible on less sensitive headphones, it is bothersome when paired even with the oft-maligned Apple iBuds. In other words, to hear music cleanly, you will need to have rather large, non-portable friendly headphones on. Of course, with Ultrasone’s DJ1Pro and the even less sensitive DT880 from Beyerdynamic, there is no hiss problem and the warm character of the amp fits either clinical headphone very well.

Chart Disclaimer:
My recording source has disappeared in a recent move. I will be replacing it soon with a decent Firewire FA-66 machine from Edirol which can capture much better than my current and barely passable MacBook Pro. Results from the chart below should only be used in comparison with other results which I have recorded. In other words, I have no faith in the MacBook Pro’s recording capability and expect both the Touch 2G and Fireye 1 to represent better numbers and plot lines which was proven when I ran RMAA using an M-Audio USB Transit and professional Sony recorder for recording. Thus, for comparisons’ sake only, the graph below should illustrate the sound characteristics in both sources for easily to detect signal patterns: frequency response, and channel separation.

As seen below, the Fireye 1 can sustain a decent channel separation when driving nothing but an outboard amplifier, but when presented with the torturous 16 ohm Victor (JVC) FX500, its channel separation suffers. Fortunately, the audible effect is much more subtle, falling inline with the performance level of higher-end portable sources. Despite this result, for a dedicated amplifier, this result isn’t inspiring.


FE1 B2: Bass+2, no load, iT2G=loaded 16ohm, FE1 FX600=16ohm load

Below, you can see the bass roll off when compared to the Touch 2G which shows less than 1 dbl at 20Hz. This is the main reason that the amplifier’s bass resolution is lower in comparison to the Touch 2G.

FE1 B2=Loaded with Bass bost, FE1 FX500=16ohm load from FX500

FE1 B2=Loaded with Bass bost, FE1 FX500=16ohm load from FX500

Your mileage may vary – soft, but wise words which should be observed when using any amp. My iPod Nano 1G using both Rockbox and stock Apple Firmware benefited less from the warm signature of the Fireye 1 simply because it is already a warmer source than the iPod touch. However, bass jumper settings gave new lungs to the bass rolled-off Nano. A final graphic expression of the bass rolloff of the Fireye 1 is when reproducing a 40Hz square wave. Crisp, resonant bass will generally be audible from sources and amps which can produce rectangular lines. Though my current equipment is poor, the shape of the graph will illustrate the point that the Fireye 1 expounds in its RMAA charts above.


Sound Conclusion:
The Fireye 1 is a good product with good intentions. Separate left and right jumpers for passive sound equalisation is unique in any amp, but particularly at its price. And, if your source is a cold, analytical player of any format, the extra warmth given by the Fireye 1 is helpful and inspiring to certain musical genres. Whether that source is an iPod, a laptop, another DAP, or a DVD player, the Fireye 1 has a steady, warm sound signature. Adding bass makes action movies com alive and otherwise bass deficient sources move. However, the lack of attenuation makes this amplifier a hard to define product. You won’t be able to use it with line out-equipment simply because it will be to loud for nearly any headphone, and as its static volume only amplifies the noise which comes from laptops, some DAPs and other hifi equipment, it is not a great pair for sensitive earphones.

Finally, the loss of bass definition illustrated above and a comparatively small sound stage makes this Firestone product merely a static-gained wire. It is a gain device with passive equalisation which works for a few applications very well, but for others not so well.

iPt 2G, Jerry Harvey JH13Pro, Fireye 1 - not the best 組み合わせ

iPt 2G, Jerry Harvey JH13Pro, Fireye 1 - not the best 組み合わせ

Firestone’s tradition of quality products is continued with the Fireye 1, a simple amplifier which does more for volume than overall sound performance. While selectable bass jumpers for both right and left channels is a great idea, it would be better if the amp itself didn’t suffer bass roll off as much as it does. While it helps audio like laptops, going portable with it is difficult since it will be too loud with a majority of sensitive earphones and with larger, current hungry headphones, may not have enough power to satisfy their large coils.

Nevertheless, an investment of 77$ brings an impeccably made product which has a few good features and convenient, well thought-out design. If only the Fireye 1 had a volume attenuator, it would be a much more usable product.

All things considered, it is worth a Tap from TouchMyApps.


Keep an eye on our Headphone section for news, reviews, and other audio articles.

App Summary
Title: Fireye 1 Headphone Amplifier Developer: Firestone Audio
Price: $77 App Size:
  • Great construction quality
  • Flush IN/OUT jacks (one of which is metal)
  • Good, cute packaging
  • Unique passive equalisation with separate L/R channel bass jumpers
  • Even power hungry headphones get very loud
  • Audible hiss is quite loud
  • No Attenuator
  • Bass rolloff
  • Only decent channel separation when paired with low-ohm earphones


review-ha-fireye1-box-01 review-ha-fireye1-box-02 review-ha-fireye1-contents-01 review-ha-fireye1-fe-01 review-ha-fireye1-fe-apart-01 review-ha-fireye1-fe-battery-02 review-ha-fireye1-fe-chip-01 review-ha-fireye1-fe-chip-02 review-ha-fireye1-fe-chip-03 iPt 2G, Jerry Harvey JH13Pro, Fireye 1 - not the best 組み合わせ Sitting pretty next with Markuz Schulz and the iPt 2G review-ha-fireye1-fe-inside-01 Bass jumpers review-ha-fireye1-fe-ports-04 review-ha-fireye1-fe-top-03 FE1 B2=Loaded with Bass bost, FE1 FX500=16ohm load from FX500 review-ha-fireye1-rmaa-02 fireye1-squareRead more]]> 9