Hi,
I’m working on a clone BASSFACE class D amplifier that was brought in with a burnt-out power supply and a dead output section.
It’s using 10 IRF260Ns for its output.
After fixing the power supply, I noticed the drive waveform on the output had a step on the turn-on, and the low-side FETs were running hot without a load at idle.
I changed the driver transistors from 2316, 916 to 2073, 940 respectively, and doing so solved the problem with the drive waveform. However, the amplifier was getting distortion well before the clipping point. The driver transistors on the low side, especially the 2073, were also running hot when I did this. I switched back to the original drivers to see if the distortion was also present with them fitted, and indeed it was, and it was much worse.
I also tried leaving the 2073, 940 on the high side and the original transistors on the low side, which was somewhat better. I also tried other transistors like 649, 669, and the results were much worse.
Any idea on what is causing this and how I can fix it?
Any help would be greatly appreciated. (I’m kind of new to fixing class D amps 😅)
Also, the rail voltage is 180 peak-to-peak.
I’m working on a clone BASSFACE class D amplifier that was brought in with a burnt-out power supply and a dead output section.
It’s using 10 IRF260Ns for its output.
After fixing the power supply, I noticed the drive waveform on the output had a step on the turn-on, and the low-side FETs were running hot without a load at idle.
I changed the driver transistors from 2316, 916 to 2073, 940 respectively, and doing so solved the problem with the drive waveform. However, the amplifier was getting distortion well before the clipping point. The driver transistors on the low side, especially the 2073, were also running hot when I did this. I switched back to the original drivers to see if the distortion was also present with them fitted, and indeed it was, and it was much worse.
I also tried leaving the 2073, 940 on the high side and the original transistors on the low side, which was somewhat better. I also tried other transistors like 649, 669, and the results were much worse.
Any idea on what is causing this and how I can fix it?
Any help would be greatly appreciated. (I’m kind of new to fixing class D amps 😅)
Also, the rail voltage is 180 peak-to-peak.