I KILLED IT... (neg feedback)

[Buddha's Guitar Tech]

i think your words about the screens ring true.

i believe the bane of it all was using a 5R4 in place of the 5Y3. too much voltage, silly me.

However, on the fender schematic, they have 350 on the screens. With 350 on the plates as well, is that getting into triode mode?

no choke, no. and yes indeed, the screen tap is coming from the right place

original spec shows 1K 1W, i put in an MF 2K2 3W, to at least drop the screen below the plate.

i'm going to pretty much start again... get a new 5Y3, put in 22uF caps and check my 6V6s to see if they still work ok.

at least i know what it is now, i can relax a little.

[marcoloco961]

i think your words about the screens ring true.

i believe the bane of it all was using a 5R4 in place of the 5Y3. too much voltage, silly me.

However, on the fender schematic, they have 350 on the screens. With 350 on the plates as well, is that getting into triode mode?

no choke, no. and yes indeed, the screen tap is coming from the right place

original spec shows 1K 1W, i put in an MF 2K2 3W, to at least drop the screen below the plate.

i'm going to pretty much start again... get a new 5Y3, put in 22uF caps and check my 6V6s to see if they still work ok.

at least i know what it is now, i can relax a little.

I hear ya. I was in search and destroy mode for about 4 hours yesterday after the final power up revealed several issues. It was actually kinda fun troubleshooting them, finding the problems and getting it up and running. I managed to stay out of "freak out" mode and just started looking things over real good. It all seems overwhelming sometimes, but I am still fascinated by it all.

[Buddha's Guitar Tech]

You got it - learning the hard way is a good way to learn, if not a little stressful and expensive!

[Buddha's Guitar Tech]

Looking at my 6V6 data sheet (JJ) the limiting values for the screen is 450, and the typical current is 45mA - that's with a 250V plate mind you, so i was still probably overdoing it in terms of power, but something tells me the tube will survive. (i've put it down and refuse to get back into until next week!)