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(All devices are handmade to customer order)
Highlights
- Regenerative power supply works as a dedicated power generator
- True symmetrical ACSS Pure Class-A headphones and preamplifier
What's new with the HE-9 MKIII?
After 5 years and long-term tests and trials, we are ready to release the new version, featuring perfect layout technology, obviously improved sound quality, better detail and dynamics, but more analog sound, no longer harsh, and the functions are also updated:
- The preamplifier output has exclusive output buffers built in that can improve the sound quality of the preamplifier output.
- It has dual volume control that can match well with different output level sources.
- The new design uses the same board for the left and right channels, making the design exactly the same so that we can measure and adjust the boards for assembly in one unit to ensure consistency.
Overview
- Unique fully analog regenerative power technology built like a private power generator, providing the cleanest power supply, enhancing sound quality with more transparency, but analog, much better than external digital technology power processors, not to mention passive LC power filter sockets.
- Unique true feedback-free ACSS spotlight applies four channels of feedback-free output stages consisting of 8 transistors, each with 15A/150W power. The total machine capacity reaches up to 60,000uF. Four R-core transformers with a total power of 260W are used.
- The preamplifier output has exclusive output buffers built in that can improve the sound quality of the preamplifier output.
- Separate Class-A power supplies supply the regenerative drivers and the audio signal amplifiers.
- Digital four-channel volume controller with 100 relay-based steps avoids channel imbalance and improves sound quality.
- Four-channel 9-step digitally controlled, relay-based pre-volume control can adjust the source input level from 0dB to -9dB.
- Two gain modes, high gain has 20dB and low gain has 10dB, providing more flexibility for different gain power stages.
- 5 analog inputs: RCA x2, XLR x2, ACSS x1 (even with RCA or XLR inputs, the output still has ACSS available)
- 3 preamplifier outputs: XLR / RCA / ACSS
- 4 headphone amplifier outputs: 6.3MM / 4-pin XLR / 3-pin XLR *2
Detail of the Current Conveyor Technology
Unique fully analog regenerative power technology:
While audio is life, power supply is water. Pure water creates wonderful life, clean power supply reproduces wonderful sound.
The regenerative power supply is built into the device like its own electric generator. It can block most disturbances from the power line, provides ultra-clean power for the audio amplifiers, and reproduces the most neutral and analog sound of the audio signal for the system and users.
In regenerative power supply, the alternating current is converted into direct current via the regenerative input transformer and forwarded to the regenerative wave generator and driver stages through the Class-A power supplies.
A balanced regenerative wave generator produces an extremely low distortion 50 Hz wave, which is passed through the compensation amplifiers and the strong output stages. The regenerative transformers generate a clean AC power supply fed into the separate Class-A power supplies for the L and R channel preamplifiers.
The Class-A parallel PSU has a very high input impedance to avoid interference from the PSU affecting the signal parts and a low output impedance with very fast speed and high linearity; it is a very clean power supply.
Unique true non-feedback ACSS non-feedback/preamplifier technology
The HE-9 MK2 was built in a truly balanced design using the latest ACSS design. It seems complex, but in fact, it is the simplest design the world has ever had, with many components to handle the power supply.
The amplifier built into the HE-9 MK2 has only a single "voltage gain stage" for signal processing but operates in ACSS mode, so it is actually a current gain stage instead of a voltage gain stage, while normal OPA chips already contain two or three voltage gain stages. The simplest and shortest signal path produces the most neutral and least colored sound.
The HE-9 MK2 uses an ultra-low distortion single-stage ACSS amplifier that is directly soldered onto the main board. The gain stages and the diamond cross output stage operate in pure Class-A mode.
ACSS is a non-feedback technology that works with fully discrete amplifiers. Most people know that global feedback designs can deliver better values in test measurements, and that non-feedback does not perform well in tests but offers better sound for human ears.
There is a conflict here between classic circuits. However, ACSS opens a new field as it can offer a less colored, more neutral sound with very low distortion and high linearity. Thus, it can maintain dynamics, detail, and neutral sound without sounding bright or harsh.
The entire signal amplification is done in the form of current, achieved through the unique, excellent open-loop multiple output mirror. The result is an incomparably precise and extremely low distortion of the amplification signal. The entire signal path is symmetrical and all transistors operate in Class-A mode.
The HE-9 MK2 uses four channels with non-feedback output stages consisting of 8 transistors, each with a power of 15A/150W. The total device capacitance reaches 60,000uF. Four R-core transformers with a total power of 260 W are used.
Unique I/V conversion volume control technology
Also, the volume control differs from conventional technology. Conventional volume control technology implements volume control in the analog amplifier input stage by a volume potentiometer to reduce the signal. The quality of the volume control directly affects sound quality. Low-quality volume controls lose details, and channel imbalance causes soundstage distortion. Even high-performance volume potentiometers, in attenuation then gain signal mode, still cause detail loss and result in the worst S/N ratio.
In the HE-9 MK2, we have the I/V conversion volume control; the volume control is just a variable passive I/V conversion placed at the ACSS amplifier output, where the output is a current signal, not a voltage signal. The volume control is an I/V conversion, and the volume depends on converting current (I) into voltage (V). (Like R-2R D/A chips that output a passive I/V conversion) It can keep the signal frequency band flat and lose no details.
It does not degrade sound quality at any volume. After the volume control, there is a diamond cross output stage providing very low output impedance.
The quality of volume control is very important in real balanced gear.
It must guarantee that the four-channel signal control precisely achieves the real balance gear performance. If the cold and hot balance signals cannot be guaranteed accurately, the balanced output will cause large distortion, making the sound quality and performance even worse than a single-ended gear, wasting the balanced gear design and cost.
In HE-9 MK2, a four-channel digital control relay-based volume control is applied, changing the tolerance of 0.05% resistors to avoid volume imbalance between channels, achieving the best performance and sound quality of the control gear.
HE-9 MK2 has 100-step volume control, applying a Super Exponential Volume characteristic, easily matching the volume with different power amplifiers and speakers. During volume changes, the various relays break or close, which can cause slight tone changes at the output that disappear when volume adjustment stops.
Shielding
HE-9 MK2 has complete separation of the left and right amplifier channels, regenerative drivers and transformer, and even the 230V / 120V power input lines are shielded within the two thick aluminum plates.
The HE-9 MK2 uses a heavy full aluminum case to prevent the transformer's eddy currents from interfering with the circuit board.
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S/N Ratio |
>130DB |
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THD |
<0.0025 % |  |
| THD+N | <0.0025% |  |
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Frequency Band (XLR input) |
20Hz - 100KHz (<4DB ) |
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100 steps Super Exponential Volume Characteristic |
 
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| Headphone amp Output Power (Balanced class A ) |
25 ohm: 15W |
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Headphone amp Output Power (Single-ended class A ) |
25 ohm: 4W 40 ohm: 2500mW 100 ohm: 1000mW 300 ohm: 350mW |
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High gain :+20DB |
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Output Level (Max) |
9.5V @ RCA |
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Output Impedance |
10 ohm @ Preamp XLR |
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|
94K ohm @ XLR |
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Channels cross |
< -130DB | |
Channel imbalance |
< 0.01DB | |
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Power Requirement |
1 Version 100-120V AC 50/60 Hz |
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Power Consumption |
66W Class A @230V or 120V |
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Transformer Power |
260W (3 unit transformers) |
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Package Weight |
Approximately 20KG |
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Dimensions |
W430 X L485 X H123 (MM, Fully aluminium ) | |
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Accessories |
Power cord X1 |
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