Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: newguitarsmell on September 09, 2018, 03:11:55 pm
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I am a total newbie to amp building, but am definitely addicted.
I built a 5f2A and it worked nicely but very little volume. I printed out the voltage chart and tested things against the readings. Everything was looking OK, but when I got to the 12AX7 readings there was a pop, then smoke and it looked like the 5W resistor was starting to look a bit darker...
I could have accidentally connected two of the tube lugs together (I didn't think so) or?
Before the pop and smoke, as I was trying to get a reading from the 12AX7 lugs, I was hearing ground noise in the amp.. it got louder and then bam.
The cap looks OK - but I'm thinking I should replace both?
What do you think guys?
Miss Jonesy in Oregon
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Welcome.
(http://prowessamplifiers.com/schematics/thumbs/fenderPrinceton_5f2a-Schematic.gif)
I don't see a 5W resistor in this plan. Can you show/link the plan you are working from so we are all on the same page?
Pop and smoke is bad, but unspecific. You should stand well back and power-up again. If it smokes, figure where.
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A lot of kit suppliers like to use a 470Ω/5W cathode resistor for the output tube.
So, can you show us some pics of your build? And a link to the layout/schematic you used?