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1 piece E7 - AD1955 in stock and ready for immediate delivery.
E7 Highlights
6 core competencies for first-class sound quality
As a flagship DAP with interchangeable modules, the E7 features the following core functions among others:
① Huge analog circuit area of the plug-in card: industry-leading PCBA area, no headphone jacks to utilize the entire space for analog components;
② Remaining stock of the AK4497 chip: AK4497 × 2, from component selection to power supply optimization, the performance of the entire machine exceeds the typical values of the chip
③ "Intoxicated" amplifier architecture: Doubling the amplifier chips, appropriate voltage reduction, strengthen the output current, the entire machine gains top-level control, low resistance and high sensitivity make the E7 more IEM-friendly.
④ Multidimensional tuning to satisfy even the most demanding listening experiences: deep, self-developed harmonic tuning and high dynamic mode, combined with low distortion mode, can be freely switched to suit different headphone categories and listening preferences;
⑤ Better use of the pure sound system "LP OS": The advantages of non-Android are lower power consumption in the digital part, less interference, and above all more valuable power for analog circuits;
⑥ Better sounding Bluetooth module with protocol stack: an important expansion that enables the E7 to achieve a streaming experience by using FPGAs, classic Bluetooth audio chips, and Lepi's new generation of algorithms to optimize the listening experience.
4 versions
The E7, debuting with the 4497 module, will be available in two optional versions - Exclusive and Standard.
AK4497 Exclusive Edition
- <-120dB distortion plus noise, exceeding the typical value of the DAC chip
- >130dB dynamic range
- Precise op-amp voltage adjustment that adapts to different headphones
- Fully functional "Music Tuning" - Harmonics Tuning + High Dynamic Mode + Low Distortion Mode
- PVD gold-plated brass knobs and the engraved "EXCLUSIVE" logo on the AK4497 module.
AK4497 Standard Edition
- <-117dB Distortion plus noise
- Dynamics >127dB (such performance is rare in the use of AK4497 DAC portable models)
AD1955 Edition
This is a decoder and amplifier card that incorporates two legendary ADI AD1955 cores. The E7 is also the first application of this classic flagship core from ADI, which has not been updated for almost 20 years, in the field of portable HiFi.
Four distinctive features
Unique feeling of high class
The dual AD1955 chips are used for the first time in portable players, allowing owners to experience the original "1955 Sound." The new E7 is a great addition to the E7 lineup, with its clear, distinctive, and high-quality sound.
Powerful single-ended with a difference
The single-ended circuit of the two AD1955s operates so that volume control, op-amp buffer circuit, and dynamics are identical to the balanced output. No matter which jack you plug your headphones into, you will hear the uncompromising 1955 sound of the new E7.
Uniquely linked LOs
The LOs of the new E7 are optimized for the EA4. The EA4's own LO improvements were so well received in the P6P 10th Anniversary Edition that they are now also available on this AD1955 card. We have added the proprietary LO enhancement design experience from the limited edition model to the AD1955 card, realizing the dream connection of the E-series bundle (E7 + EA4).
Consistent listening pleasure
The AD1955 card features a specially designed, fully discrete automatic bias compensation circuit that ensures a consistent listening experience. Around the AD1955 chip, we have developed an extensive circuit consisting of discrete components such as transistors, MOS tubes, and resistors, which allows various audio settings to be automatically adjusted and compensated. Depending on the different audio settings, a corresponding automatic adjustment is made, and the DAC's reference current and the bias voltage of the IV converter circuit are set to preserve the AD1955's unique sound style.
The AD1955 Audio Board can be purchased separately or with the E7 DAP.
Existing E7 owners can purchase the new AD1955 at a special price of 799 CHF. Please contact us regarding this at:
- Email (info@audioessence.ch)
- Phone (+41 77 403 35 26)
PCM1792A Edition
PCM1792A is known as TI's (Texas Instruments) flagship chip and probably the DAC that best embodies TI's tuning philosophy. Together, they form the Delta-Sigma architecture "All-Star chip series" of the E7. Through various audio cards, these once glorious but now rare classic chips are given new life.
This is a tribute to the golden age and allows a new generation of audiophiles to experience a uniquely captivating sound tuning. This is the essence of the E7's swappable card design.
125 dB → 123 dB, "even warmer and sweeter"
"As the "power king" among older generation DS chips, models with the PCM1792A achieve an exceptionally high dynamic range. However, such performance is usually limited to desktop decoders that require a ±15 V power supply to deliver an output power of 9 Vrms."
The implementation of such high supply and output voltages in portable devices serves hardly any purpose other than "showing off" and proves to be impractical and suboptimal in practice. Moreover, it did not sound optimal. Too high a voltage would drain the batteries of portable devices too quickly, while excessively high analog output levels are unsuitable for portability and require significant signal attenuation, inevitably leading to loss of detail.
Therefore, in the first prototype, we found a compromise between power consumption and performance by reducing the IV supply voltage to ±5.8 V and the output power to 5.2 Vrms, achieving a dynamic range of 125 dB.
During the following exhibitions, this E7 version underwent several listening sessions. While most audiophiles found the sound richness satisfactory, a minority felt it could be further improved.
Therefore, we made additional fine adjustments, including checking whether the PCM1792A could achieve its nominal dynamic performance specifications under a ±15 V power supply according to the official circuit. We concluded that even superior performance would not improve the warm, sweet sound character. Based on this, we focused on refining the sound character and produced two new PCB versions.
The final production version uses an asymmetric power supply for the IV stage and the operational amplifiers, setting the total dynamic range to 123 dB and reducing the output power to 4.7 Vrms. This led to the final tuning: "sweeter and softer."
The PCM1792A audio board can be purchased separately or with the E7 DAP.
Existing owners of the E7 can purchase the new PCM1792A at a special price of 799 CHF. Please contact us regarding this at:
- Email (info@audioessence.ch)
- Phone (+41 77 403 35 26)
The future will be even more exciting!
Whether Select Edition or Standard Edition, there is only a limited number of AK4497 modules delivered with the E7.
During the development of the E7, we found that the only 4497 chips available on the market can even contain discrete chips within the same batch and at different times.
The higher the performance, the greater the possible variation. If you want to use two pieces of 4497 to achieve -120dB distortion, single-screening from the chip, which is already very few, and then to achieve matching, technically it can be said to be much more difficult, so the actual number of handpicked versions of the E7 is very small.
E7 is the new flagship of the E series, but also a new starting point. AK4497 is the first audio module of the E7; further new architectures, new ways of playing, and new possibilities will be realized in this piece of "good land" with great potential, so look forward to it!
