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Newb layout question
Posted: Sun 05/16/21 7:24 am
by Bane
I'm building my first amp. I'm building a 5e3 to get my feet wet before I dive into an 18 watt. I'm testing now and have run into a problem. I'm not getting proper voltage to my preamp tubes. I'm backtracking to to try and figure out where I went wrong and the first thing I'm seeing is I haven't done anything on the pins marked "Fil". I have no idea what "Fil" is. I've searched for the term and can't find anything. Can someone educate me please. Thanks in advance!
Re: Newb layout question
Posted: Sun 05/16/21 7:29 am
by JMPGuitars
Welcome to the site!
Fil is short for Filament, meaning the heater wires. Tubes don't work without them.
Thanks,
Josh
Re: Newb layout question
Posted: Sun 05/16/21 7:29 am
by Bieworm
Bane wrote: ↑Sun 05/16/21 7:24 am
I'm building my first amp. I'm building a 5e3 to get my feet wet before I dive into an 18 watt. I'm testing now and have run into a problem. I'm not getting proper voltage to my preamp tubes. I'm backtracking to to try and figure out where I went wrong and the first thing I'm seeing is I haven't done anything on the pins marked "Fil". I have no idea what "Fil" is. I've searched for the term and can't find anything. Can someone educate me please. Thanks in advance!
Fil = filaments or heater pins. On 12A.. preamp tubes it's pins 4+5 and 9 if wired parallel. And on EL84 output tubes it's pins 4 and 5.
Post detailed pics of your build + voltages measured per tube and voltages of the B+ line
Re: Newb layout question
Posted: Sun 05/16/21 10:34 am
by Bane
Wow. That explains it!! Sheesh. That was a pretty big miss huh? Going back over my layout, looks like I go from the lamp to each tube. No idea how I missed that, and I feel like an idiot for it, but thank you guys!
Re: Newb layout question
Posted: Sun 05/16/21 10:38 pm
by AussieTim
There are no stupid questions, just stupid answers, we all have brain-fades sometimes and often those brain-fades lead to a eureka moment, and the lesson is never forgotten thus becoming a better learnt lesson than if thought we understood it in the first place.
Re: Newb layout question
Posted: Mon 05/17/21 4:53 pm
by Bane
Heaters are in, now on to the next problem. Thanks again guys. That was a real "doh" moment:)