Princeton Build Questions

[Willabe]

It's this black wire in the layout...

That would be the power tube K ground connection. 

But now that I look at that in the context of this conversation I guess the resistor going to ground is taking the place of that wire now, isn't it, and that's why I get no reading...

Yep, snip it out. Fixed. 

[SEL49]

You forgot to remove the two grounding wires from pin 8 of the power tubes when you added the 1Ω bias sense resistors. You must remove two wires to completely fix. Now your meter should read correct mV on both pins 8.

[Willabe]

SEL49, yes we found that. 

It looks like there's a yellow wire soldered to pin 8 on the power tube socket along with the 1 ohm K R? Looks like it goes back over to the other 6V6 socket's K?

Nothing should be there except the 1 ohm K R.

It's this black wire in the layout...


But now that I look at that in the context of this conversation I guess the resistor going to ground is taking the place of that wire now, isn't it, and that's why I get no reading...

[Willabe]

You forgot to remove the two grounding wires from pin 8 of the power tubes when you added the 1Ω bias sense resistors. You must remove two wires to completely fix. Now your meter should read correct mV on both pins 8.

SEL49, yes we found that. 

It looks like there's a yellow wire soldered to pin 8 on the power tube socket along with the 1 ohm K R? Looks like it goes back over to the other 6V6 socket's K?

Nothing should be there except the 1 ohm K R.

It's this black wire in the layout...


But now that I look at that in the context of this conversation I guess the resistor going to ground is taking the place of that wire now, isn't it, and that's why I get no reading...

[SEL49]

SEL49, yes we found that. 

You found the yellow wire(shown as black on the layout) that connects v4 pin 8 to V3 pin 8. I don't recall anyone ever mentioning the black wire that connects V4 pin 8 to chassis ground.

[Willabe]

SEL49, Yes it was supposed to be in the last quote I posted in the reply to you, but the layout picture didn't come with it.

He says "it's the black wire in the layout...." Then he says "I guess the resistor going to ground is taking the place of that wire now."

It's in reply #99.

[BobL]

Spent the day riding mountain bikes from 10K ft down through incredible changing aspens. Hell of a day.


Got home, snipped out those wires, and set my bias. Easy peasy. I have to have the pot all the way down to get to just under 70%, but since this amp  will get used at low volume at home, I'm not stressed. I guess I could change out the resistor if I ever need to get lower w/ different tubes, but stuff is sounding pretty good, so I think I'm all set.


Thanks, everyone! Very much appreciated. Learned some stuff. Made some mistakes... learned from those too.