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Station X · 1st Jul 2019, 3:53 pm

Some DMM's have an input resistance of only 1M. If you used one of these to measure the control grid voltage wrt to chassis then I'd expect a reading of 1/3rd the voltage across R9 and R11 which would be about 8V. This is not much different form what you measured.

The higher the meter's input resistance, the higher the measured voltage and vice versa.

1st Jul 2019, 3:53 pm	#32
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Voltages on ECC83 in BlackBox Some DMM's have an input resistance of only 1M. If you used one of these to measure the control grid voltage wrt to chassis then I'd expect a reading of 1/3rd the voltage across R9 and R11 which would be about 8V. This is not much different form what you measured. The higher the meter's input resistance, the higher the measured voltage and vice versa. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.