Distortion at subwoofer output at low volume

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Hello Friends,
I just purchase 5.1 Amp kit (5 TDA2030 + Stk4392 in bridge mode for subwoofer )
& 5.1 Decoder board
I notice that 5 channel sound was ok but subwoofer sound is distorted even in mimimum volume
On 2 channel mode and 5.1 mode also
I also replace subwoofer speakers.
Any clue ?
Waiting for your solutions
 
Hello Friends,
I just purchase 5.1 Amp kit (5 TDA2030 + Stk4392 in bridge mode for subwoofer )
& 5.1 Decoder board
I notice that 5 channel sound was ok but subwoofer sound is distorted even in mimimum volume
On 2 channel mode and 5.1 mode also
I also replace subwoofer speakers.
Any clue ?
Waiting for your solutions


What is the supply voltage you use?
What is the impedance of your sub-woofer?
The datasheet for STK4392 is very sparse but indicates a chip that only drives 8 Ohm well and to a limited power level (15W) in which case it is hardly suited for bridging. The sub-woofer channel is the one delivering most power with modern music.
 
If the amplifier drives a speaker of 8 ohms single ended then in bridge mode the speaker must be 16 ohms impedance or you will overload the amplifier. This is possibly why the signal is distorted. If you used it at high power you may have damaged the amplifier.
 
Power supply is 28 Volts DC
Is that +/-28 Vdc, or just +28 Vdc (in which case the question would be whether the circuit is single supply capable)? In any case, inspect the soldering job, the STK may be lacking a supply rail.

Using one of these STKs in a modern-day kit is a weird choice, these are old parts. Worst case, these may be salvaged from scrapped electronics or inferior quality modern-day reproductions, and could be dead as received.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.