These amps are now branded as CT Sounds. Same company, same owner & same amps for the most part. Differences are that now there are voltage meters, power lights and power buttons on the bass knob and the amps come as:
500.1
750.1
900.1
1400.1
2500.1
4000.1
7000.1
125.2
60.4
75.4
125.4
& 60.4 + 500.1