Using split rail supply for single rail DC


2008-03-15 4:31 pm
I want to add a preamplifier to my LM1876T IC amp using the DC supply available, it seems to work OK when connected to the DC+ and centre tap at the bypass capacitors but there is a loud hum on the audio output, perhaps an earth loop. When connected to the DC+ and DC- rails it blows the AC fuses. I have used the same preamp (LM1036N) in a battery powered portable amp with TB820M with excellent results (single rail setup) the DC goes into a standard 7812 regulator on the preamp board with a 220uf bypass cap before it. Any help would be much appreciated, I'm not einstein I just like to build my own electronic goods rather than buying them.
Thanks all,