UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Quad 22 KT66 to 6L6 with Cathode resistor increase?

PJL · 16th Sep 2022, 10:42 pm

The early coke bottle KT66 (VT75) have a similar anode structure to the 6L6G but, as others suggest, the 6L6GC characteristics are likely to be different so you need to check the cathode current and adjust the auto-bias to set to the same as the KT66.

16th Sep 2022, 10:42 pm	#11
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: Quad 22 KT66 to 6L6 with Cathode resistor increase? The early coke bottle KT66 (VT75) have a similar anode structure to the 6L6G but, as others suggest, the 6L6GC characteristics are likely to be different so you need to check the cathode current and adjust the auto-bias to set to the same as the KT66.