I'm testing amp1b. It goes from mute to unmute, LED goes out. HMUTE drops to 0v - is this correct? No relay click so no O/P. There is some dc offset at outputs, pre-relay, what would be maximum allowed for relay to click? Also what should voltage at q4 gate / source / drain be? It's about 30mV at gate (unmuted). I'm not sure how the relay circuit works so would appreciate any help, typical measurements and where to take them etc.