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Sakib816 , 02-23-2026, 09:59 AM

Can anyone tell me how to design audio amplifier with pam8620 properly? I have designed an audio amplifier with pam8620 but there are some noise in output speaker when there is no audio input. Can anyone give me proper schematics of this circuit also. So that i can do my own circuit.

Sakib816 , 02-23-2026, 10:03 AM

This is my own schematic

QDrives , 02-23-2026, 03:37 PM

No audio input or input not connected?
What type of capacitors are C9...C12?

Sakib816 , 02-23-2026, 03:38 PM

The audio inputs are coming from another android board. All capacitor are XR7 type, SMD 0603 package. Please give me how i can improve my audio input for this amplifier? Though this is differential signal input type, this amplifier is used as single ended type. I draw this schematic according to datasheet. But there are some better circuit above datasheet requirement.

QDrives , 02-23-2026, 03:40 PM

- So what if you short the audio inputs with 50Ω to Gnd for the noise test?
- What if you replace the X7R (class II capacitors) with film capacitors?

Sakib816 , 02-23-2026, 03:42 PM

I use film capacitor, but not working. When there is no audio present, a hizzz sound is heard.

Sakib816 , 02-23-2026, 03:42 PM

Maybe there need some improvement in input side of the amplifier

QDrives , 02-23-2026, 03:43 PM

You stated that C9...C12 were X7R? That is not film, but ceramic.

Sakib816 , 02-23-2026, 03:43 PM

Yes these capacitors are mlcc

QDrives , 02-23-2026, 03:43 PM

So what if you replace these X7R (C9...C12) with film too.

QDrives , 02-23-2026, 03:44 PM

X7R is piezoelectric. Vibration will turn into voltage.

Sakib816 , 02-23-2026, 03:44 PM

I tried, i use film capacitor but hizzz sound is present

QDrives , 02-23-2026, 03:45 PM

Where does your power come from? How low noise it?

Sakib816 , 02-23-2026, 03:46 PM

Can i use this single ended signal as differential, by using potentiometer? Many pam8620 module use potentiometer at the input side to control volume

Sakib816 , 02-23-2026, 03:46 PM

The android board and this amplifier are powered by smps 12V power supply

Sakib816 , 02-23-2026, 03:47 PM

Sakib816 , 02-23-2026, 03:47 PM

This type of signal when there is no audio.

Sakib816 , 02-23-2026, 03:48 PM

Sakib816 , 02-23-2026, 03:48 PM

No audio, but noisy

Sakib816 , 02-23-2026, 03:48 PM

QDrives , 02-23-2026, 03:48 PM

If that is you power suppy, then I would say "no wonder you have a hissing sound".

Sakib816 , 02-23-2026, 03:49 PM

What should i do now?

Sakib816 , 02-23-2026, 03:50 PM

As the android board is powered by smps, i cannot change the power supply

QDrives , 02-23-2026, 03:51 PM

Where does the power from PVCCL and PVCCR come from?

Sakib816 , 02-23-2026, 03:51 PM

From smps 12V, all the power are delivered from this

QDrives , 02-23-2026, 03:55 PM

Place 1uF film cap parallel to C14.
Add LC filter from +15V in to AVCC.

QDrives , 02-23-2026, 03:56 PM

Or replace C14 with tanalum cap of 1uF.

Sakib816 , 02-23-2026, 03:57 PM

What will happen if i do this?

QDrives , 02-23-2026, 03:57 PM

Noise on the input (both audio and power) will cause noise on the output.
Piezoelectric capacitors also cause noise.

Sakib816 , 02-23-2026, 03:59 PM

Can you suggest me what type of LC value should used?

QDrives , 02-23-2026, 04:04 PM

It is a bit what you can get and have space for, but 1mH and 470uF gets you 230Hz.
https://www.omnicalculator.com/physics/lc-filter
And make sure you have aluminum or tantalum capacitors. You can add parallel some C0G/NP0 capacitors for higher frequency decoupling.

Sakib816 , 02-23-2026, 04:06 PM

Please tell me in this picture which capacitor should I change the value of?

Sakib816 , 02-23-2026, 04:06 PM

In this schematic where should i change, please tell me 😊C9,C10,C11,C12 and C14?

Sakib816 , 02-23-2026, 04:07 PM

I used mlcc capacitor only, so where i put which type of capacitor

QDrives , 02-23-2026, 04:13 PM

For the 'analog' signals, you do not want X7R (or X5R or Z5U).
Film, tantalum, aluminium or C0G (ceramic) are good. Each has their advantages and disadvantages. Just as a high(er) or low(er) ESR can be a (dis)advantage.

Sakib816 , 02-23-2026, 04:19 PM

....

Sakib816 , 02-23-2026, 04:19 PM

In this schematic where should i change, please tell me 😊C9,C10,C11,C12 and C14?

QDrives , 02-23-2026, 04:21 PM

C9...C12 to film, C14 **add** film or tantalum.
But **first** make sure you analog power is low noise by adding LC filtering.

Sakib816 , 02-23-2026, 04:39 PM

Ok, i will do some change and send you feedback

QDrives , 02-23-2026, 04:40 PM

Also make sure you measure correctly.
Do **not** use the crocodile clip, but the spring tip.

Sakib816 , 02-23-2026, 04:41 PM

ok

Sakib816 , 02-23-2026, 04:42 PM

Can you provide me with the schematic of this amplifier module? If possible. I know it’s difficult for you.

QDrives , 02-23-2026, 06:57 PM

No

Sakib816 , 02-24-2026, 03:50 AM

Is there any need of add extra filter in input side?

Sakib816 , 02-24-2026, 03:50 AM

Sakib816 , 02-24-2026, 03:50 AM

Like this one?

Sakib816 , 02-24-2026, 04:23 AM

Can i use this?

Sakib816 , 02-24-2026, 06:00 AM

Hello @QDrives