I found the amp oscillates at half volume. Either side it is fine.
So I took out the phase splitter valve and the oscillation is still there in the first 2 gain stages.
I have tried extra decoupling but that made no difference.
Removing the bypass capacitors stops the oscillation but the gain is then too small.
![Image](http://www.ckp-railways.talktalk.net/valve.jpg)