dsavitsk
MOT: ECP Audio
- Joined
- Aug 3, 2003
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I have gone through my fair share of Velleman power supplies. The first (http://www6.head-fi.org/forums/showthread.php?t=109928) was my fault as the transformer was spec'd too high for the smoothing cap. The second (http://www6.head-fi.org/forums/showthread.php?t=114261) was a little less my fault and involved a LM317 dying. Some resistors also got toasted, and which was the cause is not clear.
Anyway, I had replaced pretty much all of the parts, and have been using the PS with a Pimeta for about a year. Well, today, I was listening to the amp, left the room for a minute (this always happens when I leave the room) and when I came back there was a stink, some smoke, the led's in both the PS and the Pimeta were off, and there were awful sounds coming from my headphones.
I shut it all down (oddly, the LED's came back on before I sould shut it down.) The phones (RS-1's) appear to be unharmed, but the TLE appears to have blown and the PS is giving about 50V. Nothing else in the PS is burned up, though.
I cannot figure out what could have done this. I had it connected to my new preamp as I was testing it out. It is a high voltage tube pre, but there are blocking caps on the output, and they are intact, so it seems unlikely to have been offset fom the source. The LM317 is a National, it does not run excessively hot (and should have shut down if heat was the issue) and has been runing for a year without incident.
The only thing different about today is that the pimeta's volume was most of the way up as I was testing the preamp and checking it for noise. But the volume was not high on the preamp. The only thing suspect about the Velleman is that it does not have the protection diodes on the regulator.
Well, any thoughts? Does a TLE usually blow due to overvoltage, or something else? Has anyone who has had a blown TLE have any thoughts on anything else that might be toasted? The caps are 35V and probably got more than that, so they may need to go -- though I don't see any leaks. I tested the Pimeta opamps (the L and R, not the G yet) in an opamp tester similar to Tangents. They test fine. Clearly I am going to throw away the Velleman board and replace it with something else, but this is a bit of a mystery.
?
-d
Anyway, I had replaced pretty much all of the parts, and have been using the PS with a Pimeta for about a year. Well, today, I was listening to the amp, left the room for a minute (this always happens when I leave the room) and when I came back there was a stink, some smoke, the led's in both the PS and the Pimeta were off, and there were awful sounds coming from my headphones.
I shut it all down (oddly, the LED's came back on before I sould shut it down.) The phones (RS-1's) appear to be unharmed, but the TLE appears to have blown and the PS is giving about 50V. Nothing else in the PS is burned up, though.
I cannot figure out what could have done this. I had it connected to my new preamp as I was testing it out. It is a high voltage tube pre, but there are blocking caps on the output, and they are intact, so it seems unlikely to have been offset fom the source. The LM317 is a National, it does not run excessively hot (and should have shut down if heat was the issue) and has been runing for a year without incident.
The only thing different about today is that the pimeta's volume was most of the way up as I was testing the preamp and checking it for noise. But the volume was not high on the preamp. The only thing suspect about the Velleman is that it does not have the protection diodes on the regulator.
Well, any thoughts? Does a TLE usually blow due to overvoltage, or something else? Has anyone who has had a blown TLE have any thoughts on anything else that might be toasted? The caps are 35V and probably got more than that, so they may need to go -- though I don't see any leaks. I tested the Pimeta opamps (the L and R, not the G yet) in an opamp tester similar to Tangents. They test fine. Clearly I am going to throw away the Velleman board and replace it with something else, but this is a bit of a mystery.
?
-d
