Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: proaudioguy on February 19, 2024, 01:07:59 am
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The amp I just bought had some kind of copper cap in it. I asked Weber and they said it wasn’t theirs. Had a window cut out with some yellow electrical tape in it. I tore it apart. Looks like JB Weld holding it together. Inside, a light bulb in front of the window. 2 75Ohm 10W power resistors in series with a couple of diodes coming together at the B+ output. What kind of voltage drop are we looking at there? Is it just simple Ohm’s law?
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Wich amp ?
Show schematic.
Some pictures will help.
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The amp I just bought had some kind of copper cap in it. I asked Weber and they said it wasn’t theirs. Had a window cut out with some yellow electrical tape in it. I tore it apart. Looks like JB Weld holding it together. Inside, a light bulb in front of the window. 2 75Ohm 10W power resistors in series with a couple of diodes coming together at the B+ output. What kind of voltage drop are we looking at there? Is it just simple Ohm’s law?
For one, how is the light bulb wired? It would help if you could draw a circuit diagram of the device.
The voltage drop will depend on a couple of things, and as ever, Ohm's law applies. The role of the resistors is easy enough to predict, but the lamp (basically a thermistor) is more of a moving target.