Amp distorting from PWM generator

[Ensoniq]

I'm trying to build a standalone tone generator- amp - speaker device.

I'm using the following:

1) PWM Pulse Signal Generator from ebay.

2) TPA3110 XH-A232 30W+30W Class D mini amp.

3) Tectonic HIBM65C20F-8 full range (up to 20khz) 8ohm speaker.

4) Variable DC power supply.

5) various fixed carbon resistors


What I get out of the speaker is clicking sound, along with the pwm frequency sound.
and also when turning the amp on, for first 3 seconds there is am-radio-like distortion.
I'm supplying 14V to both
since the amp can operate in 8V-26V DC range,
and PWM generator in 3.3 - 30V.

I dont have a potentiometer currently, so i tried 10k, and 20k resistor between pwm generator and amp input, in series on the "+" terminal.

 

[Ensoniq]

correction:

below 13.1khz there is sound of PWM frequency along with am-radio-like distortion that seems like its rising in pitch.

13.1khz and above there is just clicking sound, a click every half-second

 

[Ensoniq]

any ideas what I did wrong here ?

 

[Mark Tillotson]

Is the variable DC power supply switchmode? What switching frequency?
"PWM Pulse Signal Generator from ebay." - can you identify this please?

 

[Ensoniq]

This is the pwm generator:

Signal Generator PWM Pulse Frequency Duty Cycle Adjustable Module LCD Display | eBay

 

[Ensoniq]

And this is the power supply:

DC Power Supply | 1502DD | YiHua

 

[Ensoniq]

Tried a decent PA amp instead of this cheap chip amp and it sounds fine. I guess the amp’s frequency response stops at 13khz.