Bakoon Products AMP-5570 High-End Power Amplifier

As a result of testing a custom-made PA amplifier, the AMP-5570 was found to have so much information that it was hard to believe that it was a PA amplifier, so it was remade as a pure audio amplifier. Since it is for PA, the amplifier circuit does not use SATRI-IC in order to prioritize power and dynamics over the delicacy and accuracy of the sound, and uses the same discrete circuit as the popular limited edition AMP-KUMAMOTO. One of the core technologies of the AMP-5570 is HBK(I)-IC. The official name is HIBIKI, i.e. "Hibiki". In the case of SATRI-IC, the current input and current output are the main features, but when connected to a voltage signal such as CDP, the voltage must be converted into current. On the other hand, in the case of HBK(I), the circuit itself is a voltage input, so there is no need for additional buffering or conversion circuits. Compared to amplifiers equipped with SATRI-IC circuits such as the AMP-5521, the accuracy is an order of magnitude lower, but the sound has a thick line and a sense of power in exchange for the ultra-high precision of the SATRI-IC. Because there is no conversion process and the structure is simpler, the audio signal moves faster and distortion is reduced.
The AMP-5570 can be converted into a monaural amplifier by BTL connection of two amplifiers in the same way as AMP5521 and AMP7511A. By making it monaural, the output of 100W becomes even more powerful at 300W. In addition, the BTL connection can now be easily switched using the input switching dial on the front panel.
The AMP-5570 uses a metal film resistance attenuator as standard, but you can choose a more accurate non-inductive wire wound resistance attenuator.

Balanced Input

The AMP-5570 does not use an amplification element, but uses a non-feedback non-NFB SATRI circuit that increases the amplification degree with two resistors. Since there is no SATRI-LINK but there is a balanced input at the input, an OP amplifier is used for balanced unbalanced conversion, but if the OP amplifier is used, the sound will be thicker than a pure SATRI-IC circuit. There are three inputs: balanced XLR, unbalanced RCA, and BTL-XLR. In balanced XLR, the signal passes through the OP amplifier, but in unbalanced RCA and BTL-XLR, the OP amplifier does not, so it is a pure SATRI circuit.
The AMP-5570 is a new-age amplifier that does not have a balanced input using an OP amplifier that has not been found in Bakun Products equipped with SATRI-IC until now, and a current connection that is characterized by a taut, thick-wire sound designed for PA.
Instead of employing XLR, current transfer (SATRI-LINK) was omitted. It is clear that the current transmission is technically superior, but you can enjoy the fusion with amplifiers other than Bakun Products, and you can also enjoy the change in sound quality with various RCA and XLR cables that were useless with SATRI-LINK.

output	100W+100W/8Ω/Distortion 0.8% 300W/8Ω/BTL Mono Use
input	RCA (Unbalanced) x1, XLR (Balanced) x1, XLR-BTL (Balanced Mono) x1
Gain Control	V Metal Film Resistor ATT (Standard) / Non-Inductive Winding Resistor (Optional)
Distortion rate (1KHz)	0.1%
SNR	108dB
Frequency response	10~50kHz
Phase characteristics	0° / 10kHz
size	230mm(H) x 440mm(W) x 360mm(D)
weight	18kg
power	100V, 120V, 220V, 240V/50,60Hz

*Bakun Products will gradually change its logo and name to SCL (SATRI Circuit Laboratory). Thank you for your understanding.

The metal film resistor ATT has a very large amount of information, very good sound separation, and a rich mid to low frequency representation.
The non-inductive wirewound resistor ATT has minimal distortion, very high resolution, rich low frequencies, and a natural sound with no habits despite its dynamic sound.

In a nutshell, the AMP-5570 is an amplifier that uses new technology and new circuitry, and it is meaningless to compare it with existing Bakung products. Mr. Nagai, an engineer, explains the technical background from various angles. How the circuit is done, voltage and current, negative feedback, etc.... Does this really matter to us? It's all said by sound, but.... Still, if you look at the exterior first, you will find that it is a size that has never been seen in Bakun before. It is comparable to other companies' flagship amplifiers. It's a size that can shed the stigma of being a lunchbox amp. I put it on the rack and liked its reliable appearance. How important is the visual imprint of the first impression? It's a passing grade in terms of appearance. There are parts that further enhance the design perfection of the AMP-5570. A protective plate folded with a starter is attached to the sharp part above and below the heat dissipation pin that emits the heat generated by the amplifier to protect the user. It's a novel and reassuring idea. The black front panel with a charismatic pearlescent feel, and the orange bakelite knob, which is Bakun's identity, approach with a simple but powerful sensibility.
Let's look at the back. In this product, XLR is used instead of current transmission (SATRI-LINK). It's a choice to try to make it as unique as possible. This has made it easier for high-end users to choose cables. Instead of BNC cables, which had a narrow range of choices, you can connect a variety of RCA and XLR cables that are usually available. This amp can be easily changed between STEREO and MONO. After selecting the input selector on the front as "BALANCED XLR BTL (MONO)", insert the XLR intercable into the "BTL MONOULAL SIGNAL INPUT" on the back. When connecting the speaker cable, you can connect it as shown on the back, but the + side should be connected to the right speaker terminal + side, and the - side should be connected to the + side of the left speaker terminal.
The rated power of the Bakun, which used to be displayed at 15W, 21W, 35W, 97W, etc., is now a three-digit number. 100W per channel. For those who don't know, this number may be meaningless, but it's a 21-watt 7511 BTL mono amp that plays with large speakers and mocks the output of other amps. Bakun's 100W should be considered to be capable of other companies' 600-700W amplifiers. Add an AMP-5570 here, plug in an XLR cable, and turn the selector to BTL mono mode to easily turn it into a monster amp at 300W per channel.
A hint of heat can be felt through the body of the amplifier. The warmth of a life form that says I'm working properly right now. I really liked this warmth because it seems to lead to the quality of the sound. Some of the Bakun models released in recent years captured accuracy, speed, and driving power, but had a "cool and clear" feel with a thin sound. A high-end power amplifier has to combine power, speed, and texture, but it was a sound borderline that was on the border of texture and heat. However, the AMP-5570 feels like the deep oil painting colors of the early high-end AMP-5513 with power, speed, and drive. The basic tactile feel of the sound is similar to that of a vacuum tube, and the ability to separate the sound from the speaker at high speed is excellent. A powerful driving force sends the speaker unit to the precise position. As a result, there is no part of the band that is out of balance. The microdynamics are finely adjusted, and the nuances of the performers are outstanding. Also, the secluded background is truly unrivaled. The background is black, and it looks like a black hole. Just before the music bursts out, in that pitch-black silence, when the weak instrumental sound begins, it is like seeing a ray of light in the dense darkness.
If you evaluate it carefully, it looks like the AMP-5570 is going to have a negative impact on the company's other amp sales. This is because it came out with a very realistic price list. If you want to express the texture of an instrument, I would say that you should choose the AMP-5570 over a more expensive low-end MONO amplifier. If you have two or fewer sources and you want to build an optimal audio system with one amplifier, I think it's very difficult to find anything other than the AMP-5570. In a nutshell, it's enough to connect directly to the source and use it like an intamp. Of course, it's a power amp, not an intamp, but it's okay to use Bakun's unique gain adjustment function at volume. This is possible because the balance between high, mid, and low frequencies is maintained even at low gains, and there are no restrictions on the drive of the speakers.
I've been using Bakun Products for a long time and watching it, but I'm surprised by the progress I've made so far. Quite a lot of manufacturers take circuits and mechanisms that have already been developed, and in many cases, only the chassis is prepared and released as a new one. Of course, improving what you already have can be called development, but it's more like tuning than a fundamental technological advancement. Adapting the chassis to the trends and swapping out parts and materials means tuning what has been developed in the past to your liking, not technological advancements.
* Monthly Audio (http://www.audioht.co.kr)

The first movement of Mahler's Symphony No. 1 conducted by Michael Tilson Thomas and performed by the San Francisco Philharmonic. The resolution and speed of Bakun listened to at the current output are first-class, and the rich musicality is still worthy of praise, but I wondered if it would be possible to surpass this level without SATRI-LINK, but it turned out that listening to the AMP-5570 was unfounded. The amount of information is larger, the depiction of the expanse of space and the reverberation are excellent, and energy and a sense of reality are added to each sound. A little fleshed out? In fact, let's say it's closer to the sound of an instrument. You can definitely feel the weight. I involuntarily clapped lightly. This is followed by a lively recording of Jimmy Smith's "The Preacher" that adds to the charm with a slightly rougher feel. The environment and atmosphere at the time of recording are fully expressed. Of course, the SATRI-LINK amp is great enough, but the AMP-5570 is much more realistic. The colors are more intense, the energy is more powerful, and the charm of the music itself impresses the listener. In particular, the spatial expression is rich, and the tension around the stage and the reaction of the audience are realistically approached.
Listen to Hans Zimmer's film "Dunkirk" OST "Resimental Brothers" on ATC SCM20 bookshelf speakers. Played only on AMP-5570. The very fine violin treble that blooms near the center right shows off its presence. In the center of the stage, the slightly sharper texture of the violin doubles the tension of the song, and the loud notes of the thick, thick wind instruments are "scrambled". The drum beat, which sounds like a heartbeat, is also good enough and tight. The whole stage is wide and deep. No matter how tall the AMP-5570 is, it is truly amazing to depict a vast and dense stage on a small bookshelf with no height or depth of 60 cm.
100W per channel. If you don't know this number, it may be meaningless, but the 21W 7511A BTL mono amplifier played with loud speakers and mocked the output of third-party amplifiers. Bakun's 100W should be a 600-700W amplifier from another company. Simply add one AMP-5570, plug in an XLR cable, switch the selector to BTL mono mode, and you've got a monster-class simple amp with 300W per channel. Gentle heat is felt through the body of the amplifier... It's as if some living creature is telling you that it's active, and I'm very happy that this warmth seems to lead to sound quality. What about graininess? The recent Bakun models that have been released have precision, speed and a sense of drive, but they have a thin "cool and clear" feel. However, the new AMP-5570 has eliminated that trend. The basic sound feel is similar to that of a vacuum tube, and the ability to pull sound out of the speakers at high speeds without slow corners is outstanding. The powerful driving force allows the speaker unit to be placed in the exact position. Therefore, the balance of the bandwidth is not lost. The microdynamics are well adjusted, and the nuances of the performers are excellent. Also, the tranquil background is second to none. The background is jet black and looks like a black hole. The sound of the instruments just before the song starts to burst into a dark silence is like a line of light coming out of the darkness.
* Monthly Audio (http://www.audioht.co.kr)