Swissonic SA 33

Basically this amplifer does its job as supposed, but only when powering on 230 VAC. When running on 12 VDC (also tried with 14,4 VDC - lab psu) strange thing happen: if using mic on MIC1 (talkover function), when signal goes higher then certain level (around 2/3), amplifer shuts down and recovers after around 5 seconds. If you connect microphone to MIC2 (no talkover) it works normal!!! (that means, that power amplifer probably works fine, but not the logic for talkover, which somehow puts amplifer in some standby mode).

Talkover function is fixed on first microphone channel and works ok, but no parameters can be set (music/talk ratio, release speed ...).

However, for such money that's quite good amp to use with 230 VAC.

[EDIT]
Because using at 12 V is urgent for my application, I first tried to raise voltage on 12 V input up to 15 V, but didn't help. Then I used 5A adjustable DCDC stepup, set it to 21 VDC and connect it right after the bridge rectifier after transformer (on 230 VAC line). Additional 10000 uF capacitor was added as well. This way, amplifer can also work with 10 V input voltage.