kitchen table sets No Feedback Power Amplifier Board Kit bathroom storage cabinet Home Furniture

This circuit kit is a spare part and needs to be welded and debugged by yourself. 2 pairs of high-power tubes need to be purchased separately

Please choose the kit, the finished board or the complete machine according to your personal ability level.

1 set contains 2 boards, mirror design, full price with mid-power tube, key parts are matched, PCB is double-sided 2.0 thick 70UM double copper gold-plated board, you can choose to weld the finished board

The detailed material list can be seen at the bottom of the sales sticker. They are all made of very good materials. The main body of the resistor is an expensive British FR4 non-inductive resistor. If you switch to a DALE resistor or a 718 resistor, the price will be much lower, but the effect will be reduced. buckle.

For the convenience of production, we have added a speaker protection circuit on the board, so that the safety is guaranteed

PCB size 116X90.5mm
Power: 150WX2

In the circuit design, the original designer highly respects the minimalist circuit. Their design concept is mainly to have no large loop negative feedback and attach great importance to reducing TIM (Transient Intermodulation Distortion). The designer believes that, compared with the total harmonic distortion (Total Harmonic Distortion) emphasized by the general manufacturers, in fact, the transient intermodulation distortion (TIM distortion) has a much greater impact on the subjective and actual hearing perception! After research, it is found that the transient intermodulation distortion is closely related to the applied negative feedback. If a large loop negative feedback design is used in the amplifier, better THD test data can be obtained, but such sound is not good to hear. The so-called "stone machine sound" and "transistor sound" are precisely this reason. Therefore, in this Swiss post 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 back electromotive force of the speaker, making it good The characteristic of transient response, the frequency band is extremely wide, reaching 1Hz-1MHz (+0/-6dB), such a wide frequency response greatly reduces the influence of high-frequency phase lag drift, and further overcomes TIM distortion. In actual listening Almost no "transistor sound" is felt.

In fact, the factory has already published the block diagram of this amplifying circuit on its website, but has not announced the specific parameters, because it is said that this circuit has been patented. We did a simulation test before the circuit design, and the distortion was extremely low.

The following is our own simulation test, the high-order harmonic distortion is very low

input voltage DC+_35VreachDC+_55V

Debugging only needs to adjust the only on the board -An adjustable resistor，Adjust the output midpoint。

Because it's allDCAnd non negative feedback architecture，The midpoint drift will be slightly larger than the general power amplifier，+——100MVThe appearance of is normal，The original machine is the same，Good heat dissipation will make the midpoint more stable