2 CH HI-END Base On Dartzeel NHB-108 Pure Power Amplifier 100W 8 Ohm With Midpoint Voltage Upgrade Module Bare PCB

Introduction:

In terms of circuit design, the original designers of DARTZEEL NHB-108 highly value the minimalist circuit. Their design philosophy is mainly to have no large loop negative feedback and attach great importance to reducing TIM. The designer thinks that compared with the Total Harmonic Distortion index emphasized by general manufacturers, TIM actually has a much greater impact on the subjective and actual sense of hearing!

It is found that the transient intermodulation distortion is closely related to the negative feedback applied. If large loop negative feedback design is adopted in the amplifier, better THD test data can be obtained, but the sound is not pleasant,The so-called "stone machine sound" and "transistor sound" are precisely for this reason. Therefore, in DARTZEEL NHB-108 amplifier, the whole machine has no large loop negative feedback design, and only a small amount of negative feedback design is used locally. The input circuit will not be affected by the reverse electromotive force of the speaker, so it has good transient response characteristics. The frequency band is extremely wide, reaching 1Hz-1MHz (+0/- 6dB) Such a wide frequency response greatly reduces the impact of the phase lag drift in the high frequency band, further overcomes the TIM distortion, and can hardly feel the "sound of the transistor" in the actual audition. Which has obtained JI good transient response and low transient distortion. The sound is loose and natural, which is very pleasant.

The biggest disadvantage of the original circuit is that the midpoint potential is high and unstable, which is about+/- 50mV. The original dartzeel power amplifier is equipped with improvements in order to allow consumers to regularly detect and adjust the midpoint voltage.

Later, in order to solve the problem of midpoint voltage, the original Dartzeel machine adopted the method of adding Farad capacitor. After careful adjustment, the midpoint voltage can be basically controlled within 10mV. The cost of adding this Farad capacitor to the original Dartzeel machine is as low as about $3000. We have also tried to use farad capacitor, which has also been used for more than half a year. The midpoint voltage has indeed stabilized, but the main problem is that the farad capacitor capacity is too large, which not only makes the midpoint voltage stable very slowly, but also brings damage to the sound quality. As a result, we have increased the startup delay to more than 10 seconds. It often requires a second startup to stabilize the midpoint voltage.

We have studied Dartzeel NHB-108 for more than a year. After many debugging, we specially designed a new ultimate upgrade module for the midpoint voltage. This module is the most important upgrade! This module ensures that the midpoint of Dartzeel NHB-108 is within 1mV. Active servo technology protects your expensive audio system and completely replaces the immature farad capacitor of the original machine!

The installation of this module is very simple. It only needs to be overlapped on the amplifier board. On the basis of not changing the circuit structure of the amplifier and not using the farad capacitor, this module has successfully stabilized the midpoint voltage within 1mV, and is not limited by the cold engine, the hot engine, the static and the large dynamic. The midpoint is very stable and very fast. It can be said that it is the ultimate upgrade module of DARTZEEL NHB-108.

Parameters:

Input voltage: DC +/-55V (Transformer not less than 250W)

Output power: 100 W RMS @ 8 (Hi) et 2 (Lo) Ω. 160 watts RMS @ 4 (Hi) et 1 (Lo) Ω.

Gain:26 dB sous 8Ω

Input impedance: > 30KΩ

Frequency response: 1 Hz -- 1 MHz, +0, -6 dB, 10 Hz--100 kHz, +0, -0.5 dB THD: < 1 % 7 Hz-77 kHz

SNR: > 105 dB (A)

Power consumption: 150W au repos, 1000W au maximum

PCB size: 115mm*80mm (AMP), 95mm*80mm (Midpoint upgrade module)

NOTE: This is stereo bare PCB, 2 PCS amplifiers PCB+2 PCS midpoint upgrade module PCB. All components need to be matched by yourself.