In a message dated 8/6/2006 12:57:25 AM Central Daylight Time, miltron at mindspring.com writes: How did the 5-500 do ? Did anyone use it besides McMartin ? M I think the McMartin used the 4-500???? I may be wrong. The Collins 820D-1 and 820D-2 used the 5-500 tubes which performed very well the D-2 was great on positives. DAve