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Hi,
I've built an SE tube amp, basically on the AX84 High Octane schematic ... anyway, I'm not on the first build, I actually finished quite few, but this one is very strange ...
Here are the fact: I got a low frequency hum in the speaker, EVEN with primary winding of OT in air! that's right, I tested with the OT connected just to speaker, and the PT started, and his secondaries not connected, and tubes removed too!
I initially thought that the PT are inducing somehow a current in the secondary of the OT, witch is connected to speaker, so I removed the OT out of the chassis, and put a lot of space between those two transformers, but the noise is still present, and starting right after I switch on the power switch ...
Is very odd, I have two separate transformers, with no input (for OT) and no load (for PT), and the speaker is humming ...
I don't know if I made myself clear, english is not my native language
, but if someone ever heard such thing, please give me a clue, because I begin to suspect something alien here ...
Thanks.
LE. I've read most of the topics since a lot of them are regarding hum of many kinds ... well, I guess none is comparing to mine
I mean, hum without the OT tight in the circuit ... that's something else, isn't so?
More on that behavior: the hum is goes instantly when I switch off, I have an tube rectifier schematic, with russian 6u5c tube, which has separate heater winding, 6.3V too, not 5V. Seems like a problem with that PT, but I don't figure out how he introduce hum in output speaker, without any connection in the amp, all wires just disconnected ...
I've built an SE tube amp, basically on the AX84 High Octane schematic ... anyway, I'm not on the first build, I actually finished quite few, but this one is very strange ...
Here are the fact: I got a low frequency hum in the speaker, EVEN with primary winding of OT in air! that's right, I tested with the OT connected just to speaker, and the PT started, and his secondaries not connected, and tubes removed too!
I initially thought that the PT are inducing somehow a current in the secondary of the OT, witch is connected to speaker, so I removed the OT out of the chassis, and put a lot of space between those two transformers, but the noise is still present, and starting right after I switch on the power switch ...
Is very odd, I have two separate transformers, with no input (for OT) and no load (for PT), and the speaker is humming ...
I don't know if I made myself clear, english is not my native language
, but if someone ever heard such thing, please give me a clue, because I begin to suspect something alien here ...Thanks.
LE. I've read most of the topics since a lot of them are regarding hum of many kinds ... well, I guess none is comparing to mine
I mean, hum without the OT tight in the circuit ... that's something else, isn't so?More on that behavior: the hum is goes instantly when I switch off, I have an tube rectifier schematic, with russian 6u5c tube, which has separate heater winding, 6.3V too, not 5V. Seems like a problem with that PT, but I don't figure out how he introduce hum in output speaker, without any connection in the amp, all wires just disconnected ...
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