From GL My question was: Do you think the transistors will survive when the input power is +/-12VDC and the output is a 4 Ohm transformer load? I think the transistors will be well below the SOA (safe operating area) considering the low voltage. I would put a fuse and a small 12 volt automobile lamp on the output (in series with the transformer) for initial testing, then later substitute a 1 ohm CSR so you can actually measure the current supplied to the transformer. Lamps can be dandy limiters if operated within their ratings. If only a resistive load on your transformer, you will be safe. If you are going to be playing with resonance on the secondary, all bets are off as you may get severe resonance rise of voltage on the primary. In this case MOV's or tranzorbs may also be helpful to protect your amp from destruction. Make sure your transformer can handle (has enough inductance) for the lowest frequency and power you intend to pass through it without saturating, as this could cause current spiking. The 12 V lamp will save the day here. This amp is a nice basic design, and has built in current limiting (T4, T5), but this may not work under all conditions. Be sure to conservatively fuse your batteries. Prevention is prudent. Best of luck.
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