Y’know it’s kinda funny. Most guitar amps I work on, if I wanted to elevate the filament heaters (the glow-y thingees in the tube, attach to a low voltage source as reference to ground,to get rid of some noise) I would attach a resister like 100 ohms from each heater wire and attach it to the cathode to the power tubes.
Kinda like you did, by attaching the cathode (pin 3) to the heater (pin 4) but you didn’t have a resistor. I guess that could have fried the LED I’m not sure.
Please take this with the love that’s intended but I would start with your solder technique. To me it looks like your iron isn’t hot enough, and on many of the joints you don’t have enough solder.
Let’s start with the iron. Crank that sucker to 700f. (I don’t know Celsius) If your tip is small, and the iron came with a larger one, use the larger. It should be wider than a pin on a socket, but not big enough to touch multiple pins at once.
The reason you would want a larger tip is it cools down when you touch things. A bigger tip retains heat better. I change mine based on what I’m soldering. You don’t need to do that, just use a bigger one.
Next, the thing I like to do is make sure solder fills the whole pin, but doesn’t drip down.
- I make a little hook (half loop) in the end of the component, go through the pin and have the other side being “pulled†firm by an alligator clip wire or helping hands.
- tin the end of the soldering iron with a dab of solder. This is to increase contact heat to the parts, not smear like glue.
- touch iron on one side of the pin, and “paint†the opposite side pin and (hook)wire with solder. Do not push the solder into the iron, sure it melts, but you need the components hot. “Where the heat go, your solder flowâ€.
- you should lift the solder iron away in like 2-3 seconds, like 5 at the most. If it isn’t working, chances are it’s not hot enough.
- when I had a small bad iron, I could “get away with†using a small bottle of liquid flux and wetting the area before soldering. But it does leave residue you have to clean when finished. You could also try “cleaning†up the area to be soldered by taking some super high grit sand paper and scuffing it up a little.
But everyone develops their own techniques, and mine aren’t “right†per se. just remember, if you ever get lost in the woods, just start talking about soldering, and someone will pop out and tell you why you’re doing it wrong.