I'm looking for a site that sells suitable valves for my Leak stereo 20. Two have gone, that is they no longer glow . One still gets hot but given the lack of light and the white powdery deposit within I must assume its gone besides I'm getting no sound.The valves in question are EL84(yugoslavian) and EL519A which is a beast that stands about 4" high and has an ( I think its called) anode cap which connects it to the underside of the amp. It sits where the rectifier valve once stood and I think its called a regulator valve. Thought of trying Chelmer valves but wondered whethr anyone had any suggestions.Cheers!