Bakoon Products HDA-5230MK2 Compact Headphone Amplifier

The HDA-5230MK2 supports only current drive. During the development stage, a SATRI-IC circuit was developed that allows the current drive system to be pulled out directly without passing through the voltage drive circuit, resulting in a smaller product size and more precise operation without the conversion process. Since voltage drive and current drive have completely different sound characteristics, the current drive method provides a unique and attractive sound that is difficult to hear in other amplifiers.

Driving headphones with current results in less distortion and more precise reproduction compared to voltage drive. Many headphones have less undulation in the impedance frequency response, and when those headphones are used with current output, it is possible to hear much more information that cannot be obtained with voltage drive.

On the rear panel is a pair of RCA jacks for input from the source device and aDC power supplyadapter connection terminals, and a single 6.5mm single headphone output terminal is located on the front. The volume stage in the current drive system increases volume in proportion to the impedance size of the receiver, so that at the same volume a 300Ω headphone can be approximately 10 times louder than a 32Ω headphone. For this reason, the current gain adjustment switch on the HDA-5230MK2 is used to set the volume to "HIGH" when connecting to a low-impedance receiver.

The current output drives the headphones with a very high impedance, resulting in low sound distortion, and the frequency response varies with the impedance curve of the headphones, making it suitable for almost all headphones.

The advantages of the HDA-5230MK2 will be more pronounced for those who listen at low volumes. This is because the signal-to-noise ratio remains intact at low volumes and carries a clean signal. This is especially advantageous when listening to large-format classical music, where there can be a large difference in volume within a single piece. As with the company's other amplifiersHDA-5230MK2uses a gain adjustment method that adjusts the amplification value by adjusting the signal's amplification ratio. In this case, the problem of left-right deviation at low volumes can be solved in one fell swoop, not to mention the reduction in signal-to-noise ratio that can occur due to attenuation after amplification.

The result is a very fast start-up, dynamic and powerful bass, a sense of presence, and a deep, vast, and quiet background and sound field. This is a sound that sets it apart from many headphone amplifiers. The overwhelming sense of presence and resolution, the amazingly natural sound reproduction and depth of the live sound will not tire you out even after long periods of listening. It is more comfortable than you can imagine, and once you hear it, you will not want to let it go.

The HDA-5230MK2 is a model that removes the built-in battery from the previous HDA-5230 model, which was a battery-powered model, and instead uses an external DC power supply. This means that the HDA-5230MK2 can be used at home without being limited by battery usage time, and can be used with a portable battery pack when on the road.

Current output gain (times)	Low: 32Ω/0.38, 100Ω/1.2, 200Ω/2.3, 600Ω/6.9 High: 32Ω/0.75, 100Ω/2.3, 200Ω/4.6, 600Ω/13.7
Distortion (1mW)	Load resistance = 32Ω/0.032%, 100Ω/0.01%, 200Ω/0.005%, 600Ω/0.004
Maximum output: 1% distortion maximum output (mW)	32Ω/9.3, 100Ω/27, 200Ω/54, 600Ω/93.5
Frequency Response	10kHz ~ 100kHz
Headphone Impedance	33Ω
Current Output Input Equivalent Noise (-db)	Low: 32Ω/105.6, 100Ω/100.7, 200Ω/97.7, 600Ω/96.8 High: 32Ω/109.4, 100Ω/104, 200Ω/101.7, 600Ω/95.7
Applicable Impedance	8-600Ω
Gain	4.5x
Power supply	5VDC/500mA
External Dimensions	78mm(H) x 235mm(W) x 295mm(D)
Weight	Approx. 300g

*Bacoon Products will gradually change its logo and name to SCL (SATRI Circuit Laboratory). Please note that the logo and name will be changed to SCL (SATRI Circuit Laboratory).
When I played music, I was puzzled by the completely different sound from what I had heard on my receiver. Although I had selected a song that I usually listen to, the bass was richer than I had ever heard on the HD800S. In "Send my love" from Adele's <25>album, the bass beat and Adele's voice pulled the song along. Listening to the song, which usually has a heavy rhythmic feel to it, with the HDA-5230, the beat was further emphasized and the amount of its resonance was clearly increased. Fortunately, the bass was not unnatural, as is often the case when the bass range is boosted by EQ, but was presented as naturally as if it had been there originally. If you listen to the HDA-5230 with a reference receiver that has been in it for a long time, you are likely to experience a sound very different from what you remember. This is one of the unique characteristics of the Bacoon amplifier. The HD800 series receivers used by the author have long been used by many people as the reference in the headphone world, probably because they provide a stable sound with no bias in any part. However, when the HD800S met the HDA-5230, it turned into a receiver with an intense bass sound that I had never heard before. Usually, the impedance listed in detailed product specifications is based on the 1 kHz band. In other frequency bands, the impedance may be different. For example, the HD800S has an impedance of 300 ohms in the 1 kHz band, but an impedance value of over 600 ohms at 100 Hz. In the case of voltage-driven systems, assuming that the amplifier performance is sufficient, the difference in receiver impedance by frequency band does not affect the volume, so the same volume can be obtained over the entire bandwidth. However, as mentioned above, with current drive systems, the impedance affects the volume, so the frequency bands with higher impedance are heard with more emphasis. Since the character of the HDA-5230 changes completely depending on what kind of receiver is engaged, it does not seem very meaningful to examine the character of each frequency range separately. However, when looking at the overall sound texture expression part, if we divide the overall sound expression into two parts, sharpness and softness, the HDA-5230's expression is closer to softness; even though it is closer to a V-shaped tone in terms of timbre based on the HD800S, it is not irritating and does not tire one out after long listening. This is a common feeling I have when listening to other receivers. If you find your system sounds too gritty, the HDA-5230 will solve the problem.