Quick Question about the Hoffman Bias Checker Kit

[coreysan]

In the kit, most tube pins get their continuity by inserting the 20 gauge wire through the circular etched board hole, and it travels
down and touches the corresponding socket base pin.

In the case of pin 8, my wire touched the socket base pin, and I thought, wait a sec - it shouldn't touch
it, so the current can go through the meter first.

Did I understand it properly? As I understand it, if the current traveled through the wire *and* the meter simultaneously,
then it sort of defeats the purpose of having an inline meter. Right?

The hoffman instructions don't clarify that point, anywhere I could find.

[EL34]

The description of how it works is on the assembly page here
http://el34world.com/charts/BiasChecker3.htm

How it works

The way this Bias checker works is that pins 1,2,3,4,5,and 7 pass uninterrupted through the Bias Checker from the tube base to the tube socket.

Pin 6 is not used in most 8 pin tubes and so there is no need to wire it up.

Pin 8 from the tube base is sent out to a Multimeter set to dc milliamps and sent back to pin 8 of the tube socket.

You are basically reading the current flowing through pin 8 by putting your meter in line with it.

You can see the current flow in the diagram above left.

The current flows up from pin 8 of the tube base, out through the multi meter and then from the multi meter to pin 8 of the tube socket.

The meter is set to

DC milliamps

and the range is set to

under 200 milliamps

on the meter.

Most amps will only be biased to under 50 milliamps per each power tube

[EL34]

And the image on the assembly page clearly shows that pin 8 is interrupted
The current is made to flow out and through your meter so you can measure the bias current