Re: Free Standardised Valves
Nick,
I'm afraid your comment that the errors are +-5% is wildly optimistic. I have just plotted the errors from the data in your "Valves-2.xlsx" file, and I enclose the results. The error graph is on a 3rd tab on the Excel spreadsheet - and the data is derived in the Data tab.
As you will see only one tester - your VCM163 gets what I would call "close" to the DC results. Most of the testers are within a +-10% bound with Vg below -25 volts (i.e. -15 to -25V). They mostly look pretty wild as the Vg drops below the -25V point.
I don't know whether all the testers make the -25V point a significant one, where a change of grid voltage range is required. It certainly does on my Mk.IV, and I know there is something dodgy going on around that switching point with my own VCM.
Richard
|