The Yulong company is far from new to the audio market. With thoroughness worthy of the best Japanese and German companies, Yulong methodically closes one market segment after another. They have solutions both in the budget segment and in the Hi-End area (I talked about their DA8 combine), and relatively recently a balanced A28 headphone amplifier appeared in their product line (besides the more expensive A18), and it’s about the A28 I and I will tell you.
What is this amplifier for? The fact is that most really good headphones require a sufficiently powerful signal to reveal their potential, which ordinary sources cannot provide. Sometimes it is clearly noticeable in volume - the headphones sound trite quietly, even if you turn the knob to maximum. But often there is just enough volume for the headphones, but they do not give out the maximum of high-quality sound that they are capable of: the bass control is lost, the high frequency sound fades, the resolution deteriorates. Most often such tight headphones can be identified by their impedance and sensitivity. For headphones with an impedance greater than 60 Ω (approximate figure), the amplifier is highly recommended. The same with headphones, whose sensitivity is below 100 dB / mW (the figure is also approximate, there are exceptions).
As you might have guessed, these two indicators are far from a panacea. As an example, I can cite one of my favorite AKG K702 headphones (now available on the secondary market at a great price). Their sensitivity is 105 dB, the impedance is 62 Ω, in principle, in terms of numbers - not the tightest headphones. In fact, it is highly recommended that an amplifier with a higher than average output power is recommended for these headphones, otherwise you will lose bass. Looking ahead, I will say that I listened to them with many amplifiers, but only with the A28 I heard that they still have low frequencies, and very good ones.
Yulong has a great Saber line. It includes products almost top. I say almost because in development the company has two D8 DACs and an A8 amplifier that are absolutely uncompromising in all parameters of the device, and sometime they will become the top, but at the moment it is the Saber series that is the top of the company's product line. This model range includes devices made in a similar design. The A28's aluminum case is the same size (250 mm x 200 mm x 55 mm) with the rest of the Saber products, so the A28 perfectly fits into the same rack with other devices, allowing you to assemble a very high level desktop system.
The Saber line is a little eclectic, because it has a number of products out of production (do not miss the chance to get them at a good price), but the most relevant are: P18 air conditioner, D / A amplifier DA8, A18 and A28 headphone amplifiers D18. In the near future, another interesting model will be released - DAC / amplifier D200, which is almost the analog of DA8 at a price 2 times lower.
There is a little confusion with positioning amplifiers. Two current models A18 and A28, both are made according to the balance scheme. The A18 is built entirely on discrete elements, while the A28 combines the use of operational amplifiers with the classic diamond buffer circuit on transistors. The amplifiers differ in price - the 18th costs about $ 900, while the newer 28th is sold on eBay at a price ranging from $ 600 to $ 700, depending on the seller. Despite these differences, it is worth saying that the A28 is still not the youngest model, since in terms of power these amplifiers are close, it is rather a new approach that offers a different sound. Also on the side of the A28 - a wider selection of inputs / outputs.
According to Yulong engineers, the main goal in developing the A28 was to achieve high sound quality while maintaining a moderate price tag. After trying various combinations, the engineers stopped at the OPA 2604 opamp and MJE243 / 253 transistors connected in a diamond buffer circuit.
Since the A28 is a balanced amplifier, and the developers did not want to make it highly specialized, they made it possible to connect a regular source using two RCA connectors. In this case, OPA1632 is used to convert a normal input to a balanced one.
Do not save on other details: the power transformer from the Canadian Plitron, connectors Neutrik, potentiometer from the Taiwanese Alpha.
Specifications
- Signal to noise ratio:> 120 dB
- Total harmonic distortion + noise: 0.0005%
- Crosstalk:> 100dB
- Frequency range: 20 Hz - 20 kHz, ± 0.3 dB
- Output power of balanced output: 600 Ω - 400 mW, 300 Ω - 700 mW, 150 Ω - 1.3 W, 32 Ω - 2.5 W
- Output power of unbalanced output: 600 Ω - 120 mW, 300 Ω - 200 mW, 150 Ω - 350 mW, 32 Ω - 800 mW
- Power Consumption: <30W
- Dimensions: 250 mm x 200 mm x 55 mm
- Weight: 3 kg
Design and management
All Saber products are made in two colors, you can choose between silver and black. I prefer the first option, because I like the texture of aluminum in its raw form.
The appearance of the A28 is quite simple, but it is the restrained simplicity of high-end technology. All controls and connectors are located on the front and back of the device. Ahead are: a switch with a green power indicator described around it, a volume control and three combined connectors. I would like to dwell on the connectors. The fact is that the developers decided to provide the user with maximum opportunities for connecting headphones. The right-most four-pin XLR-connector is designed to connect balanced headphones with the appropriate plug. The other two connectors - combined. They can connect a normal 6.3-mm TRS-connector or three-pin XLR connectors. In the first case, the outputs will be used for unbalanced headphones, and in the second case, you can connect headphones with a balanced cable equipped with two three-pin XLRs.
Outputs for unbalanced headphones are signed as High and Low. According to the company, the right output is designed for very sensitive headphones with low impedance. Its reduced power protects such headphones from overloads, which can be catastrophic for them. Most ordinary headphones should be heard from the left output - there are no restrictions, and, therefore, the sound will be better. By the way, during the experiments, I came to the conclusion that the Low output is better suited for in-ear headphones, since the noise is less noticeable on it.
Thus, to the A28 you can connect any cable from the existing ones for large headphones, and the clever switching system on the relay hidden inside the amplifier will take care of the rest.
The main thing that the developers are warning about is not to use adapters with a balanced output to an unbalanced one, as this may cause damage to the device. If your headphones have a simple cable with common ground - use the appropriate output, or take care of replacing the cable (in the case of the A28 this makes sense).
The volume control is a very pleasant, properly selected effort to rotate, no noise, smooth adjustment - all as needed.
On the rear panel are the entrances. Two balanced tri-pin XLR and two unbalanced RCA. Between them there is a switch that allows you to choose one of two pairs. The developers do not recommend connecting signal sources to both inputs at the same time, as this negatively affects the sound quality. In the corner of the rear panel there is a standard socket for the power cable, combined with a fuse and a network voltage selection switch.
On the side faces there are gaps for heat dissipation, as the amplifier heats up during the work - try not to block them.
Sound
To listen to the amplifier, I used the following equipment.
- MacBook Pro Retina Late 2013 as a source
- Yulong DA8 via USB as a DAC, connected to the A28 by balanced cables
- Fidelia as a player
- Philips Fidelio X1 Headphones (Balanced Connection), AKG K702 (Balanced Connection), ZMF Fostex (Balanced Connection), Fischer Audio FA-003 Bog Oak Limited Edition, Sennheiser HD800
- Lossless Records
The main thing that should be taken into account by the possible users of this amplifier is first of all the A28 is intended for balanced connection. Balanced output provides more power to the headphones, and by the sound it wins over the unbalanced one. However, the unbalanced output is very good, but here the main question is why to agree to half measures. Given the fact that most top-end headphones provide for the replacement of a standard cable, transfer them to a balanced connection is not difficult. I, for example, used the services , they operated on my AKG and Philips, turning them into balanced and providing them with appropriate cables.
It is clear that the amplifier of this level has excellent detail, resolution and tonally neutral. These are necessary, but not sufficient conditions. I, perhaps, will depart from my tradition of describing sound in general and concentrate on the sound of individual headphones with this amplifier.
The biggest surprise, of course, was with the AKG K702. I'm already used to the fact that the 702 is a headset with a small amount of bass: most browsers on the Internet are writing about it, and my own experience of listening to them with amplifiers confirmed it. It is easy to come to terms with this, since these AKGs are not buying for the sake of powerful bass, their main advantages are detail, transparency and three-dimensional scene. After listening to them with Yulong A28, I realized that they actually have a bass, and a deep and very textured one, just for a full disclosure of the K702 you need a powerful amplifier. With this role, the A28 copes perfectly well, and the headphones acquire those low frequencies, which they lack with other sources.
Philips Fidelio X1 I am inclined to consider one of the best headphones of the last five years. Dear stylish design, thoroughbred, slightly darkish sound with high resolution and dynamics, reasonable price (although in Russia it is not so good), undemanding source - these are the main advantages of X1. Of course, speaking of the undemanding to the source, it is worth understanding that good headphones sound as bad as the source itself is. Therefore, after all, listening to the Fidelio X1 with the first available player is not worth it. Yulong A28 helps them to open up to the limit of possibilities - improves the length and resolution of the HF, makes the MF not so remote, evens out the tonal balance, highlighting it a little.
ZMF Fostex is another example of headphones that are demanding to gain, regardless of the characteristics. The isodynamic emitters used in them are distinguished by unprecedented detail and are very complex in the full disclosure, requiring a more powerful amplifier. I used to listen to them with a decent DIY amplifier based on the AD823, but the A28, of course, takes them to another level. Literally every aspect of sound improves: resolution, dynamics, channel separation, scene construction. ZMF is not bad at all, but with good amplification they start to sound at a level comparable to many top isodynamic solutions.
Of course, it was interesting for me to check the A28 in unbalanced mode and compare it with the output of the DA8 headphone amplifier. For this, I used the wonderful Fischer Audio FA-003 Limited Edition Non-Profit series and the top of it all - Sennheiser HD800. Immediately it should be said that the unbalanced output noticeably lags behind the balanced counterpart, although it slightly surpasses the built-in amplifier DA8. With an unbalanced output, you get noticeably less bass and a narrower imaginary scene. Although if you do not compare the outputs with each other, then in the unbalanced mode, the A28 is very good: the dynamics, details, resolution are quite at the level of amplifiers in the same price category.
Very good unbalanced output with sensitive IEM: the almost complete lack of noise, pleasant detail and power.
findings
Very worthy continuation of the line. I don’t know if the A28 will replace the old model A18, as promised by the company’s representatives, or will become an alternative available in parallel, but in any case, the A28 is an excellent amplifier for those who want to get the most from their headphones, even at the cost of switching to a balanced connection . As usual with Yulong, the A28 is one and a half times cheaper than its counterparts from competitors, which is especially pleasing to those who are not ready to pursue quality, regardless of the price.
Unfortunately, there are no representatives of the company in Russia, although there are a lot of offers from verified sellers on eBay, but residents of Ukraine may turn to .
The article is based on materials .
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