01-01-2017, 02:05 AM
There are some points to note in the schematic I find interesting. As I gather C60 is the smoothing capacitor that supplies R12. Notice the HT line goes to the output transformer in series with R35. This 1K resistor was once off circuit so I can confirm the HT line directs across it. Further evidence is the huge shock I got from the cap (with the set unplugged months ago).
So this HT line heads to R12 which is 33 K. Now here's the punch line: If supply is 230 and the ECH81 anode 95 volts, R12 would drop 135 volts with the anode (triode) drawing 13 milliamps. So, oddly I get 0.013/135 = 10384 R. That's a fair way from 33 K. Or 34 K if you wish. My only explanation is the drop across the windings??
So far as I know the Mullard and Telefunken tubes are not different.
Given I'm hoping to learn as I go along I am trying to get a bit sharper with the schematic.
I like to ask myself these questions so I share my observations although I ought to be celebrating New Year. Anyway Happy New Year let's hope it's a good one.
So this HT line heads to R12 which is 33 K. Now here's the punch line: If supply is 230 and the ECH81 anode 95 volts, R12 would drop 135 volts with the anode (triode) drawing 13 milliamps. So, oddly I get 0.013/135 = 10384 R. That's a fair way from 33 K. Or 34 K if you wish. My only explanation is the drop across the windings??
So far as I know the Mullard and Telefunken tubes are not different.
Given I'm hoping to learn as I go along I am trying to get a bit sharper with the schematic.
I like to ask myself these questions so I share my observations although I ought to be celebrating New Year. Anyway Happy New Year let's hope it's a good one.
