Greetings Everyone!
I have a Fender Ramparte that I use as a "living room" amp. It's lower wattage and looks more like furniture than a typical amp, so it works when I'm sitting around in the living room and wanna jam quick. If you're not familiar with the odd-ball Ramparte, it's a Single Ended 6L6 powered amp, about 9ish watts, with a pair of 12ax7s in the preamp, no tone stack or master volume control.
The other day I was playing it and the amp suddenly went quiet and some of the magic blue smoke escaped. After inspection, the two 100ohm resistors off the secondary that supplies the heaters were toasted. Visually, everything "looks" fine, save for the 2 resistors in the heater circuit. I've checked the voltages on both the secondaries off the PT, and they seem fine. Heater is 6.3v. Both secondaries, and primary, have a bit of resistance, and aren't shorted. No blown fuses anywhere. No caps are popped. I replaced the to 100ohm resistors with half watt metal film (exact replacement). I powered it up without the tube in it, and everything appears fine. The B+ voltage is within spec, the voltage across each resistor is a little over 3v, the 6.3v powers the lamp just fine. I put the preamp tubes in, everything is still fine, same story. As soon as I add in the 6L6, those resistors start heating up and are ready to smoke again.
I have a new 6L6 on it's way, but is there anything else I can/should be testing before I risk damaging a new tube? The old 6L6 tube has continuity across the heater pins, and the other pins (plate, grid, screen, etc) are not shorted to each other or to the heater pins. Granted I'm not testing this tube under load or once heated. Anyone seen a tube blow out the heater circuit resistors before?
Thanks in advance for any help or suggestions!
I have a Fender Ramparte that I use as a "living room" amp. It's lower wattage and looks more like furniture than a typical amp, so it works when I'm sitting around in the living room and wanna jam quick. If you're not familiar with the odd-ball Ramparte, it's a Single Ended 6L6 powered amp, about 9ish watts, with a pair of 12ax7s in the preamp, no tone stack or master volume control.
The other day I was playing it and the amp suddenly went quiet and some of the magic blue smoke escaped. After inspection, the two 100ohm resistors off the secondary that supplies the heaters were toasted. Visually, everything "looks" fine, save for the 2 resistors in the heater circuit. I've checked the voltages on both the secondaries off the PT, and they seem fine. Heater is 6.3v. Both secondaries, and primary, have a bit of resistance, and aren't shorted. No blown fuses anywhere. No caps are popped. I replaced the to 100ohm resistors with half watt metal film (exact replacement). I powered it up without the tube in it, and everything appears fine. The B+ voltage is within spec, the voltage across each resistor is a little over 3v, the 6.3v powers the lamp just fine. I put the preamp tubes in, everything is still fine, same story. As soon as I add in the 6L6, those resistors start heating up and are ready to smoke again.
I have a new 6L6 on it's way, but is there anything else I can/should be testing before I risk damaging a new tube? The old 6L6 tube has continuity across the heater pins, and the other pins (plate, grid, screen, etc) are not shorted to each other or to the heater pins. Granted I'm not testing this tube under load or once heated. Anyone seen a tube blow out the heater circuit resistors before?
Thanks in advance for any help or suggestions!
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