No video :(

LM1875 KIT UPDATE

Подписаться 3,6 тыс.

Просмотров 1,2 тыс.

50% 1

Using a cheap $2.00 LM1875 kit.
Previous tests output ~0.1 THD.
Improvements demonstrated after swapping out 1 Ohm 1 Watt for 10 Ohm 1 Watt resister.
Scope: Digilent 14bit Analog Discovery 2 Pro
Software: Audio Analyser Suite (Author - / @thestuffmade )

Опубликовано:

29 авг 2024

Ссылка:

Скачать:

Готовим ссылку...

Добавить в:

Мой плейлист

Посмотреть позже

Комментарии : 10

@andryusha4308 8 месяцев назад

Думаю, что звукотехники и конструкторы всё описали в datasheet. Нет никаких причин выдумывать что-то своё. 🤗

@JohnAudioTech Год назад

Interesting, but somewhat baffling findings here. That resistor is part of a boucherot cell, which helps to stabilize the amplifier when driving reactive loads. Changing its value from 1 Ohm (recommended value on the datasheet) to 10 Ohms may compromise the stability of the amplifier with certain loads. Now the baffling part of why the distortion is less: The resistor and the series capacitor form a high pass filter that is high impedance in the audio spectrum. It should have no effect on the distortion performance. Is it possible a high frequency (well outside the audio spectrum) is included with the test signal or picked up by the amplifier? This could affect the readings if the signal is conducted to ground through the boucherot cell. The 10 Ohm resistor would lower that signal current. Another scenario is something else changed which affected the distortion.

@Elecifun Год назад

Of course your absolutely right. I tried this as an experiment just to see what would happen, influenced by ESP project 72. It was a first look using 8 ohms. With a 4 ohm load this falls to pieces clipping on the negative at low input. Project 72 uses a 100n instead of the 220n in this circuit. I will swap out the 220n for 100n as this is how I learn. I do not and will probably never have the skills and knowledge you have, no matter how many times I watch your videos. I tinker and enjoy the test gear. Thank you for your input, it is a learning experience for me.

@VIPINSAINI_20 Год назад

Still waiting for your new video to come

@Sonic_Ox Год назад

Interesting stuff Elecifun. If John can't explain the improvement then I haven't a prayer lol. I guess the ear is the final arbiter. Seems audio is a delicate mix of science and magic lol.

@Elecifun Год назад

All I can tell is it is good for 8 and 6 ohms (speakers are 6) but with 4 ohms it all goes south, messy negative clipping at low input. I agree with the magic part, definitely some phenomena in the electric electronics arena.

@andryusha4308 8 месяцев назад

Думаю, что звукотехники и конструкторы всё описали в datasheet. Нет никаких причин выдумывать что-то своё. 🤗

@Elecifun 8 месяцев назад

@andryusha4308 LOL many ways to build with the LM1875... The datasheet shows a typical circuit, its not set in stone. Experimenting with circuits helps me learn. Rather than just copying.

@andryusha4308 8 месяцев назад

С наступающим новым годом!

@Elecifun 8 месяцев назад

@@andryusha4308 Have yourself a great new year. All the best from the UK