Recent content by molexey

To be fair, try touching the capacitor with something non-conductive, such as a plastic pen. If this noise is coming form the cap you will notice a change in intensity.

This noise from the capacitor in a snubber. Noise intensity varies with temperature. As the amplifier (the capacitor) warms up, the noise decreases. This noise also disappears when the power supply goes from active burst mode to normal mode. You can check it, just load the amp around 2w.

Do you have any measurements? I tried LM4562, LME49720 and OPA1612 and I didn't notice any difference.

Have you tried swapping the right and left opamps?

I think this is just a unification of used materials and processes. For example, I have seen two versions of the amplifier with 3 pcs. capacitors ChengX 2200 uF or 6 pcs. Samhwa 1000 uF caps. Anyway total capacity is 6600 uF and that's more than enough for the TPA3250. For the note. I paid for...

@Otaku+, you are misinformed. All of the four DAC channels are used for TPA325x balanced inputs (pretty clever solution) and two of I2S inputs are used for the Bluetooth module.

You can use a CY7C68013A board just $3. ;) Another solutions is ESP8266 for control via wi-fi.

This is not a rotary encoder. It's a potentiometer with hard stops. The STM32 doesn't control volume, it is for LED indication. Look closely at the block diagram. The potentiometer connected to the ADAU via Auxiliary ADC Input.

Please PM me. I will share a project with loudness.

Because, together, together, because. :D Frequency response — 10 nF (20 kHz -1.3 dB) Frequency response — 6.8 nF (20 kHz -0.7 dB)

I don't think it's junk.

Referring to the data sheet: A 6.8 nF capacitor with a 470 Ohm resistor (which is installed) for a 50 kHz corner frequency. With 10 nF we get 34 kHz. I would install the 6.8 nF cap.

With a LM4562NA op-amp the noise is gone.

This sound from the capacitor in a snubber. Sound intensity varies with temperature. As the amplifier (the capacitor) warms up, the sound decreases. This sound also disappears when the power supply goes from active burst mode to normal mode.

Yes, I reinstalled it. I didn't take all pictures. The coupling capacitors C93, C86, C70, C69 are still there. The R_in resistors also still there. But the amp didn't start. When I removed R_fb 18K resistors the amp started up as usual. Thanks for the measurements. I understand this fact. But...