UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Replacement of OC171 in an Eddystone EC10

G6Tanuki · 11th Dec 2017, 7:58 pm

Some people in the past have suggested using transistors like the AF139/AF239 in such applications - thinking "That's a UHF transistor - higher Ft so it's got to be better" - truth is, the Hfe of them is generally lower than the Hfe of a boring transistor like an AF114/115/124/125 "general band-II VHF-broadcast" one.

11th Dec 2017, 7:58 pm	#4
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 13,996	Re: Replacement of OC171 in an Eddystone EC10 Some people in the past have suggested using transistors like the AF139/AF239 in such applications - thinking "That's a UHF transistor - higher Ft so it's got to be better" - truth is, the Hfe of them is generally lower than the Hfe of a boring transistor like an AF114/115/124/125 "general band-II VHF-broadcast" one.