28-06-2017, 09:25 AM
(27-06-2017, 05:30 PM)Nick Wrote: ... But if you scraped the paint off an OC71, presto! You got an OCP71...
...then Mullard got wind of that and filled OC71s with opaque gel...
I think you will find that the reason for the opaque gel was not a spoilsport tactic by Mullard but because dealers were getting complaints of mains hum with transistor radios!
If the paint got scratched for any reason and vents in the rear of the cabinet let in light, operation in a room illuminated by artificial light produced mains hum!






