Review Work (Headphone Amplifier)

Firestone Audio Bobby : The Monster

Firestone Audio Bobby arrived in!

Firestone Audio Bobby arrived in!

Thanks Kerry Ko for sending me their flagship headphone amplifier, Firestone Audio Bobby (1,199USD) for review.

It is not regular that we have an over 1000USD headphone amplifier sitting here on our table, I have to admit that when Bobby (Pure Class A and True Balanced Design AMP, without DAC feature) came to our place, I am indeed interested to plug it on and listen how it sounded, to be frank I have never been so happy.

Design, Ergonomics and Build Quality

Bobby is a big and tough guy! First of all, it is really tough and you can see how much attention Firestone Audio did on the Bobby. Bobby is their flagship model, I am not surprised to see Bobby is one of the toughest audio equipment that I have ever came through. Professional is the term that I will use to describe design and outlook of this headphone amplifier.

From Left there is a good screen, and some button layout that you can refined the control.

From Left there is a good screen, and some button layout that you can refined the control.

It is nice looking to my standard, body and front panel are in brush finish. There is also something like anti-vibration cone at the bottom of Bobby, this is a real thoughtful design.

Bobby is a pure class A headphone amplifier, now everybody knows that pure class A amplifier will exhibit significant level of heat, Bobby is no exception, however Firestone Audio had given a lot of attention to this issue, there is hole (Or we can say it as ‘heat outlet’) on both of the side, while I am surprised Firestone Audio does not make hole at the rear side, I found that Bobby will not become too hot if the surrounding temperature is not that hot. Even it is a hot day and I just turned on the fan (Not air-conditioner system), I still can lay my hands on the body of Bobby after hours of usage, of course it is hot but not the level that will cause possible burnt to my skin.

Heat can dissipate out from here

Heat can dissipate out from here

While I am satisfied with the build quality and designation of Bobby, I have not really fully satisfied with the ergonomics level of Bobby. I am not saying that it is bad in any way but I do think that it can be further refined in some way :

  • As a professional headphone amplifier, you can select the source (XLR/RCA), Stage(Normal/High) and gain (Low/Medium/High). However, Bobby will not remember your last selection so you have to reselect it every time you turned on the Bobby. Now this is really inconvenienced although it will not consume a lot of time, but I still think that this have to be refined.
  • Volume level can be fine tuned and you can get the most appropriate volume level (Because it is 0.5db for every steps of increments), I am happy with the fine tuned option but the volume increment level is really too big sometimes, it is from -60db to 45db.
  • Although I understand that normally high end headphone amplifier will not have feature like ‘bass boost’ or anything that disobey the rules of ‘audiophile sound quality’, but sometime I really wish to have this feature or something similar to having a more exciting sound.
  • At +23db volume level, there is some humming sound when I stop my music, I have never really exceed 0db for my listening volume though, as I said, -10db to -22db is perfectly good for my headphones (Q701, GMP400, HE500 and HE400, Soundmagic HP-100). Although I don’t think any headphone will really need the 22db but I just have to report this.
From the back

From the back

However, in another way this feature is good as well, even if I am using another amp, I will turn off the volume before I turning on them too, this feature is good but I am just saying that the -60db (Starting volume) to my normal listening volume (Normally -20db for most of the pop and -8db for most of the classical musics).

One thing that I will have to give compliment is the volume knob, you can feel each of the increments (softly) as you are turning it, the display is nice and beautiful thanks to the yellowish digit that makes the looks so classic and handsome, even with the looks and touch I can easily known it as a higher end headphone amplifier, remember, Bobby is a standalone headphone amplifier, no built in DAC features.


Features that is rarely seen on other headphone amplifier

Some of the features that I love on the Bobby, and the first one must be :

  • The ‘push to mute’ button (Push the volume knob) is a very brilliant feature. I found myself using this feature quite often.
  • The display unit is excellent, clear and informative.
  • The headphone jack is excellent, combine ‘low impedance’, ‘high impedance’ and ‘3-pin balanced headphone jacks’, versatile and smart.
  • Finetuned-able volume level
  • Solid and tough body, with steady base leg.

A Standalone Headphone Amplifier

Yes, Bobby is a standalone headphone amplifier. A standalone headphone amplifier is not something new but I will have to say this again. Firestone Audio currently has 4 products in their FireWay lineups(Which is also their top of the line):

Tobby (Pure 24/192 DAC with balanced/non-balanced output)

Rubby (50 Watt Class D power amplifier)

Libby (DAC with built in headphone amplifier)

Bobby (Pure Class A fully balanced headphone amplifier)

I am fairly sure Firestone Audio’s professional level as I have tested their Firecute and Fireye series, I have left impressed and using them day to day in real life. This is the reason why I am expecting very much from the FireWay series, especially for a price that can directly rival with Burson Audio HA-160D (Also the latest Burson)Graham Slee, Beyerdynamic A1 and some other amp that you can think of in the 1000USD+ price range. While they were already gaining good name in game, this seems like a tough game for Firestone Audio to play, however, they intention is clear, making as perfect device as they can.

Audio Quality

DAC/Source : Arce MDAC3(Connected via Yulong Audio U18 or Arce MUA1), iFi Audio iDAC,Yulong Audio D100 II, JDS Labs ODAC, M2Tech HiFace, Kingrex UD384 (With UPower) and Firestone Audio CustomCute.

Headphone : AKG Q701, German-Maestro GMP400, Hifiman HE500 (Silver cable), Hifiman HE400 (Black canare cable), Soundmagic HP-100, Creative Aurvana Live!, Shure SE535/SE425, Hifiman RE400.

Interconnect and cable : Charleston Cable Company top of the line UP-OCC cable.

Playing media : Foobar 2000 V1.1.14A, all music files are in loss-less formats and play while Fidelizer (A software that use to turn off unnecessary software and system, for better audio performance)

Burned in : Bobby has been burned in over 500 hours.

AKG Q701

Bobby does not wow me on the very first second I listened to it, not because of it is bad or whatsoever. However, after some tracks I found myself loving this headphone amp very much. First of all, the ‘generous’ kind of sound signature is really something different and I have never encountered. What I am described as ‘generous’ kind of sound signature’ is something that is big, big and big.

I have never felt Bobby ‘exhausted’ when playing my music files, the energy keep flowing and sound is always ready to come through the headphones to my ears. Please noticed my describe term, the music keep flowing, I guess this is the most attractive selling point of the Bobby, the huge, transparent, spacious and flowing sound signature is something that is very attractive and addictive.

Generally I can say Bobby has a balance and neutral (with slightest towards warm) sound signature, it does not have any personality, in fact it plays it role pretty well as a headphone amplifier, it always has a big and spacious sound-scape that helps to project excellent sound quality, you just have to make sure that your DAC is up to standard.


One thing that I like about Bobby is it just purely act as media between your DAC and your headphones, it does not add any coloration nor flavour, it is a glass of plain water, let you know your DAC more. I paired the Bobby up with Arce MDAC3, sound characteristic of MDAC3 was spot on, which is smooth, gentle and heart-soothing. If I paired it up with Firestone Audio CustomCute, the straight forward, dry and transparent sound signature is spot on as well, same goes with iFi Audio iDAC and YuLong D100 II as DAC. The sound that you are hearing is the sound signature of your DAC and headphones, Bobby doesn’t add anything, it just amplified what your DAC has, this is signature of a good headphone amplifier.

Most of the time I just paired up the Bobby with Arce MDAC3, because this is my favourite DAC of all time. I have paired all of my headphones with the Bobby, however headphones that I love the most are German-Maestro GMP400 and AKG Q701, I am not saying that HE500 and HE400 from Hifiman are not good, but for my genre of songs and preference, I think both of them are good but not what I really want. Soundmagic HP-100 is closed headphone that I love the most, sound signature is clean and neutral, while still give me deep and natural bass response. Without saying much, I will primarily using Arce MDAC3 as source, while AKG Q701 and German-Maestro GMP400 as my headphones (Also little of Soundmagic HP-100).

First album that I have played is album ‘At the Movies’ by Dave Koz, clarity is really nice and instruments are all natural sounding through MDAC3 and the Bobby, the funky track, ‘The Pink Panther’ (track 6th)is nice, treble is nicely showed with smooth transition, I don’t think anything is lacking here, saxaphone has good and roper sound, while other instruments are not dead at here, they are all well placed and presented nicely through my headphones. I love the performance of Q701 over GMP400 with this album or should I say saxophones, because you can hear the air is vibrating inside the saxophones, clearer and thicker than when I played it with GMP400. However, treble on GMP400 is slightly better in my honest opinion, extended further and clearer, both of them are not slouched. I can’t say which is better, in fact I am using them all of the time. When the track ‘it might be you’ (Track 9th) played, wow! Vocal of India Arie was so natural and seducing, romantic song I can say, saxophone of Dave Koz blend nicely with vocal of India Arie. I knew someone might expected Bobby will bring the vocal forward by a bit, however this is not the case, as far as I understand Firestone Audio house sound signature, they will not bring anything forward intentionally, which is good, for those who expected forward kind of vocal or feel the music close to your ears with no distance, make sure you have the right DAC and headphones.


Album ‘Sonatas of Faure and Franck’ by Arturo Delmoni (Violin) and Meg Bachman Vas (Piano) is a must have for piano and violin lovers, not only because both of the violin and piano are well played but also because they are very well performed together. The music is very nice, Bobby played it with smooth and full, Q701 is full with the music and all presented in a natural, unforced behaviour, music type that Q701 is very capable of. I can say numerous of music album that has two or three types of instruments, but I must mention the album that I really love, which is album Apollo by Daniel and Carey Domb, acoustic guitar and violin are playing nicely together, through Bobby, music just flow and keep coming, natural sounded and huge sound is what I get, 100 percent of eargasm and non-stop enjoyment.

For most of the music Q701 and GMP400 is enough for me, however, for album that demand big and deep bass such as album ‘Patriot Games’ and ‘The Gladiator’ by James Horner, I prefered something such as Soundmagic HP-100 and Hifiman HE400/500, which has nicer and textured bass. I prefer the HP-100 though, because of the deep and solid bass impact that this type of music required. I have to say that Bobby is not soft in terms of bass reproduction or speed, everyone knows that ‘the hits’ (track 4th ) needed speed and insane level of bass to make it sounded good, the bass that Bobby gave is hard hitting and well-textured, when the song became faster and faster, I can see Bobby handle it with ease and effortless, as long as your headphones are capable, Bobby will not hesitate to sound its best.

I am definitely not saying AKG Q701 nor German-Maestro GMP400 is lacking in bass, definitely not the case, in fact I love the bass performance of Q701 and GMP400, they are well-textured and have good depth/presentation/tightness, however they are very short decay and almost no rumbling, bass is too clean and not that warm to satisfied the bass demanding crowd or bass demanding songs, but for classical and normal pop song, I found the bass of them is really just nice, not even closed to what I will call as ‘bass-light’, depends on what are you using as benchmark.




I put on the famous record ‘9 Symphonien’ by Karajan and Berliner Philharmoniker, Bobby play it with good soundstage and instrument separation, imaging and instrument positioning is nice especially with the imaging capable headphone such as HE400 and HE500, although Q701 has spacious and wide soundstage, I personally think that its imaging capability is not that excellent especially compared directly to headphone such as HE500. Same goes to the album ‘Vivaldi 12 Concerti’.

I played the album ‘IV’ by Fourplay, jazz is something that HE500 really capable of, I am not saying that Q701 nor GMP400 can’t perform nicely with jazz, they are fairly good at Jazz music but HE500 simply performed nicer in Jazz, the extra bass impact and tighter bass do jazz music a good favour. Needless to say much, bass has been given good authority and adequate power, mid is warm and nice (HE500’s nature), expressive and smooth. Diabolus in Musica by Accardo is my all time favourite, I listened to this album in 4am every day, I simply love skill and sound of violin from this album, I am loving it more through Bobby.

The most impressive factor regarding Bobby is how it showed true colour of your DACs and headphones, it does not add up ingredients nor sugar to your music, it just performed the most honest music to everyone’s ears. I can see why I am loving it but I can predict for those who are looking for more excitement and boost up in any frequency might not be interested in the Bobby. I am not saying that Bobby is lifeless nor boring sounding, in fact it is quite full and lively, but Bobby is perfectly balanced while giving slight (Very minimal) of warmth. Detailed level, soundstaging, imaging, positioning, dynamic are all fairly saying the price tag, this is a good amp that made for those audiophiles clearly demand more in their music.

Final Verdict


1,199USD might not for everyone, but sound quality of Bobby really is one of the finest in the price range. The reason why I am being so obsessed with Firestone Audio is because they tend to impress me with excellent quality of products, no matter it is Fireye, Firecute or Fireway, they are all impressive and I am actually using them day to day even I am not reviewing them.

Bobby done all the job that an excellent headphone amplifier should done, a balanced and neutral (Slightly warm, very slightly) along with excellent clarity and transparency, what I would describe as true audiophile kind of sound quality. I love the Bobby and it has become my primary headphone amplifier when I am not doing any review. I found myself very difficult not to like the sound quality of Bobby, especially after I changed the original power chord to Rein Audio ower chord, the differences are even more appealing.


This monster from a Taiwanese company bring me different type of experience, I am really hoping that Firestone Audio will have more and more good and higher stuff coming.

2 thoughts on “Firestone Audio Bobby : The Monster

  1. Impressive amp for its price. Best heard with balanced XLR setup. Mute function is so handy, why doesn’t other headphone amps have this?
    Firestone now offering an upgrade. Send your amp back to the factory, and they will install circuitry and posts for connection to a pair of stereo speakers! Check them out on facebook.

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