Re: Help on the sound coming from the transformers
Posted: Mon Mar 28, 2005 12:52 pmetc wrote:I finally finished my first amp and plugged it in. Once the tubes get warmed up I hear a whirling sound coming from the transformers. I think it the 1650P audio transformer. It sounds like a DC motor spinning. I quickly turn of the unit in case something goes wrong.
Is this normal to hear this sound? From what I'm told there's going to be some vibration and to expect some sound but mine seems a little loud. It does it on both mono blocks. I don't even have the speakers connected to it.
Thanks for the help.
Hi etc,
Sounds like a feedback oscillation. Disconnect your negative feedback taps and re-check your transformer connections before trying it out again.
I would also short the RCA input and add some type of resistive load on the speaker outputs. A 8 ohm, 50W resistor would be fantastic, but even a 1K, 1W resistor would be fine for idle testing.
Shannon