avc oscillation problem

[Adrian Hall]

Hi, I'm new to this forum but I'm experiencing problems with a recently built preamp using intact audio AVCs.

The unit sounds great with cd; I can now hear the bass in all parts of the room instead of just the rear two corners. There is also more detail retrieval overall. I'm very pleased.

However, when I plug in my phono pre amp, a World Audio Design Phono3 that I built a few years ago, I get a pulsing through both speakers at a rate of approx 4 pulses per second.

I've looked at the circuit diagram for the phono 3 and it appears that, when connected to the AVCs, there is an LRC resonant circuit created. The attached document shows the phono 3 circuit.

I enjoy dabbling in electronics but I have a very limited understanding of how things work so I was wondering if anyone has any suggestions as to how I can resolve this problem?

Many Thanks

Adrian