Firestone Audio Bobby
Pure Class A fully balanced headphones amplifier review
Introduction
We have stumbled upon a great product that has caught our attention in the crowded market of headphone amplifiers. This market is characterized by both price and different philosophies regarding design and construction. We are talking about the Bobby amplifier by Firestone Audio a Taiwanese company with good connections in both the U.S. and Europe.
Firestone Audio, also known as FSA, was born in September 2003. As reported on their website we can see that:
As an audio product manufacturer, we specialize in Pre-Amplifiers, Digital Integrated Amplifiers, Power Amplifiers, Headphone Amplifiers, DAC, etc. FSA is a company that owns the products of its brand name. FSA aims to promote any kinds of amplifiers, making them part of our daily life! Our intention is to help people discover the important role that music plays and the power of the finest melody. Based on this, all of our products are fabricated in Taiwan, and our factory is just located nearby where we are so that we can better monitor and control the quality of our products. FSA’s complete product line is a combination of the quality of MIT (made in Taiwan) guarantee and reasonable price. The flexibility and efficiency enable FSA to become a real competition in this industry. FSA, located in New Taipei City, has so far been a partnership with many nations’ companies, like in Australia, Europe (the Netherlands, UK, Denmark, Norway, Sweden), HK, Japan, North America (Canada and USA), New Zealand, South Korea, South Africa (arranged in alphabetical order). The scale of FSA is still expanding! With the view to spreading across every continent, we are looking for any chances of potential cooperation from any countries. Ever since 2003, FSA has launched more than 25 products on the market. From the smallest size, affordable price, to the luxurious audio feast, we have got many choices catering to different individual needs. Our motto is ”Listen to our clients! Be humble and learn from them!” This is the principle that we keep it in mind and we trying our best to offer the sincere after-sales service. Every member in FSA accepts our clintets’ opinions and is willing to improve what has been seen as a weakness. FSA keeps in touch with every current working partner to enhance each other’s bound! We truly believe our company will be getting better and better with the mutual cooperation! The final goal to us is to become an outstanding company of good quality.
As you can see their approach is concrete, and the marketed products look to combine high quality at reasonable prices. A combination that we believe perfectly applies to a balanced headphone amplifier such as Bobby.
Design
Although the name Bobby may cause you to smile or laugh, the design and construction of the device is totally serious and leaves no room for doubt. The amplifier is fairly big and hefty, weighing around three and a half kilograms. If the height and width is pretty standard, what makes Bobby stand out is its’ depth of 33 cm. This may not arouse attention at first, but in the end, it is much deeper than most headphone amps on the market today. Therefore, once purchased, you will need to take into account the right space in which to place the unit. Like all the amplifiers in class A, the heat produced is quite considerable, however, the designers at Firestone Audio have managed to solve potential overheating problems by creating fissures along both sides. Precisely for this reason we can confirm that the unit doesn’t overheat even after several hours of use. Although, as a precaution, an appropriate amount of space should be left around the amplifier. The Bobby is characterized by four TI OPA604 operational in mono. The volume is controlled digitally by a couple of TI PGA2311 used for consumer audio systems and high-end professional ones. The front panel is well made and is characterized by a bright LED dislay that indicates the various functions such as the selected input type, the type of output swing and the volume level.
The volume knob rotates freely thanks to a digital controller and if it is pressed you can mute the amplifier. Next to the volume knob there are two 6.35 mm unbalanced inputs, one for low impedance headphones and one for high impedance ones. In addition to these inputs, Bobby has two XLR female 3-pin inputs that allow you to connect the left and right channel of the headphones in balanced mode. On the left side of the LED display we have the on/stand-by power button, while on the right there are 3 vertical buttons. These being the source button which allows you to select the type of input line between unbalanced and balanced. Then there is the stage button which allows you to select a different output voltage swing on the headphones between normal and high. Finally, the gain button adjusts the volume in different steps which are split between Low (0.5 dB), Medium (1 dB) and High (2 dB), ranging from -60 dB to a maximum of +45 dB. Together the IEC socket on the rear panel, as well as the unbalanced and balanced line inputs and the main on/off button complete the unit. We would like to point out that when you switch off the amplifier using the main on/off button or remove the power cord to turn it off, the Bobby won’t store any adjustments you may have made in its memory when you turn it back on. This feature is a little bit annoying but fortunately it doesn’t occur when Bobby is switched off using the stand-by button on the front panel.
Listening test
Like any self-respecting listening test performed in our small studio using our reference audio system, we always try to ensure that each device performs to its best ability. This process involves, for example, submitting the product being tested to a burn-in process that lasts for at least 72 hours. We generally avoid using the supplied power cord. We believe that the use of our custom cables can improve the overall yield of the product as well as only using balanced line connections. The songs used during our listening sessions are based on hard rock music and pop jazz with high levels of quality and dynamic range. On the advice of the technical department of FSA, we reduced the output level of our DAC to a minimum of +6 dBu to avoid overloading the input stage of the amplifier. Having done this, we started using the Bobby in unbalanced mode. Used together with both the Sennheiser HD 600 and HD 800, the amp showed good synergy and a good linearity in returning the sound source. We didn’t notice any particular differences between the low and high inputs, even if we noticed an increase in volume and a higher density of the sound message when using the high socket. What really impressed us, especially considering the price of the unit, was when we used the amp in a balanced configuration, for both line inputs and headphones. Here the amplifier radically changed its performance by unleashing an energy that we wouldn’t have expected and managing to drive a demanding headphone such as the HD 650 in a rather authoritarian way. This is the headset that has amazed us most by far due to its performance together with the FSA product. Our HD 650, to be fair, has been modified by removing both of its foams pads that cover the headphone drivers in order to extend the response at the highest and lowest part of the sound spectrum.
In order to drive the HD 650, we used a customised balanced cable made in pure OCC silver that has helped to slightly open the frequencies in the upper-middle of the sound spectrum thereby slightly emptying the midbass that is a little more predominant in the stock configuration of the headset. In this way, the bass of the HD 650 has taken on the right weight thereby becoming more precise as regards articulation and extension. The voices and mid-tones are the most beautiful part of this combination together with highs frequencies making their presence more linear. The Bobby is definitely a nice amplifier with a really rather neutral tone that neither adds nor subtracts practically anything to or from the incoming sound source. Throughout our testing we always kept the stage setting on High to ensure the highest output voltage swing on the headset during every listening session. The perceived differences between Normal mode and High favor the latter as regards greater transient accuracy, greater focus and a more open sound stage. With the HD 800 driven in balanced mode, Bobby is able to keep up with the Sennheiser flagship model giving greater weight on bass and manages not to mess up the tone that made this headset famous. The HD 800 is often merciless in revealing the flaws of the recording that you are listening to and in combination with the FSA product this time is no exception. Even with an headset like the HD 650 which is less precise and monitor like than the HD 800 we were able to detect a few flaws present in the most modern recordings. All this confirms the neutral sonic nature of Bobby. In our listening session we didn’t perceive any fatigue on the part of the amplifier with different musical genres and even less with the more demanding requirements such as dynamic range. The large, clear, spacious sound performance therefore makes listening interesting and engaging.
Final thoughts
In our humble opinion the most interesting key factor of Bobby is how it present itself in comparison with your DAC and your headphones, revealing the strengths and weaknesses of both in a genuine way. We, in principle, are lovers of neutrality and if possible we try to avoid sources or devices that color the sound audibly, although many audiophiles may not agree with us. However, the neutrality of Bobby doesn’t mean that it is lifeless or dull. Thus avoiding absolutist and apodictic claims, we limit ourselves to simply saying that this amplifier made by FSA is perfectly balanced as regards sound response, while giving a very light and very minimal preponderance towards a warm tone. The detail, the reconstruction of the sound scene and the dynamic characteristics are all excellent especially when compared to the price. In conclusion, Bobby is definitely a very good amplifier that, while useful also to professional users, helps music lovers get more out of their music.
Personal opinion
I personally think that FSA has fully achieved its purpose in creating a product worthy of note. I was really amazed by Bobby, both due to its neutrality and its yield with the Sennheiser HD 650. Given its performance it could cost much more than its current selling price. To tell you the truth, it doesn’t have the same authority and power of our reference HPBA-2 S but Bobby is the first ampflier that I would recommend to any audiophile who wants to buy a balanced amplifier headphone without having to spend a large amount of money. The premises expressed by Bobby are decidedly positive. Let’s give, therefore, FSA the opportunity to surprise us soon with other devices like this one that have all my complete approval and recommendation.
Score
- Scoring110
- Sound quality [1]
8 - Bang for the buck [2]
10 - Measures [3]
8 - Build quality [4]
8 - Versatility [5]
8 - Overall rating
8
- 1. Sound quality is really very good especially with dynamic headphones
- 2. The bang for the buck factor of the unit is very high compared to the quality
- 3. Very good linearity measurements on different parameters
- 4. Build quality and aesthetics are really good
- 5. Versatility is wide-ranging and achieves its best with dynamic headphones
