To be extra sure test this bridge with low voltage and small currents. Use max 24 VAC and 1-2.2 kohms load. Measure that you get correct voltage. 24 VAC will generate 24/1.11 = 21.6 V if you don't have any smoothing caps. If you don't get fullwave rectification you will get only 10.8 V. Don't use any smoothing capacitors for this first test because you won't be able to notice if you have full or halfwave rectification.

Connect this ultra high performance rectifier bridge in your amp now and good luck. You won't be disappointed.