BrianL wrote: ↑Sun Jun 01, 2025 4:23 am
So what temperature do you guys use to solder ground wires to the back of potentiometers, I've always had trouble with that, it always took forever to get hot and solder, usually didn't stick and I always worried about burning up the inside....
I would skip that step for the reasons you mention and make grounds to the ground lug.
For the shielded runs, make a pigtail lead by wrapping a piece of thin wire around the exposed shield braid and soldering.
Use toothed washers on the pot bushings to make good contact between the pot case and the chassis.
In general run your tip temperature hot, I set my WESD51 at 700F.
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I ordered a new 290FX transformer and some other parts that I want to replace because I've soldered and unsoldered them so many times they look like crap now.
Parts should be here later this week...
Brian
Got my new transformer and a bunch of new parts, I bench tested the transformer.... I've got a solid 6.5 VAC across the heater wires, that's what I need!!!!
So the build begins again, good luck to me, I've done research, watched videos, how to build, how to dress, what to watch out for...
I'm smarter than I was b4, it's gonna work this time.....
Brian
Hey All,
Starting to think I'm talking to myself right about now, but I know I've posted nothing new to talk about yet. So here you go!!!!
New parts, new wiring...one of the pics shows a cool resistor support I 3D printed to hold the 470R 5 watt resistors off of the 2.2K resistors on the 6L6 tube sockets. I also supported the 2.2K resistors with a 2 position wiring terminal. Every time I got near the 470R's They would move down against the 2.2K's and I don't want them shorting out on each other. They're glued to the support with silicone.
Brian
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I'm glad to see you're making progress! I don't think it will be an issue with the 5 watt screen resistors, but adhering one side down like that may inhibit some of the ability of the resistor to dissipate heat. Just something to monitor once you get the amp running.
Also, it is hard to tell in the photos, but you may want to go back through the amp and touch up/reflow your solder joints.
db,
I was worried about movement or vibration eventually fatiguing and breaking the resistor wires on the 470R's so I mounted them.
I'll look at the joints and probably will resolder them now that I have a new decent setup it should work better.
Thnx for comments...
Brian
