One channel my my F5 clone (Peter Daniel's boards) is humming badly. The other channel is silent.
The hum happens only when I have a signal connected (whether or not signal ground is connected). I even get hum when I connect the signal in to star ground.
I measured the resistance between board ground and star ground at .2 ohms. There is only one ground connection between the board and star ground.
Any clues about how to go about diagnosing this?
The hum happens only when I have a signal connected (whether or not signal ground is connected). I even get hum when I connect the signal in to star ground.
I measured the resistance between board ground and star ground at .2 ohms. There is only one ground connection between the board and star ground.
Any clues about how to go about diagnosing this?
Try evaluating the noise with shorted inputs (hot to ground)
with the input grounds not externally connected to each other.
😎
with the input grounds not externally connected to each other.
😎
The hum happens when there is no external connection and the right signal input is shorted to star ground.
No such luck 🙁
Would oscillation be at 60 hz? I thought that was usually a high frequency thing.
I think I found it. It's just a poor ground connection. The crimp-on ring connectors I used to connect all of the wires to star ground aren't making a very good electrical connection.
To find it, I connected a wire to the working channel's signal input and probed around with the other end to find out what wires hummed and what didn't. In the absence of a scope you have to get creative.
To find it, I connected a wire to the working channel's signal input and probed around with the other end to find out what wires hummed and what didn't. In the absence of a scope you have to get creative.
Even my problem is similar. U use cilvier F5 board and Jims 2 power boards for each channel. When there is no input its great no noise at all ver clean. As soon as connect CD player or preamp it start humm. Any practical experience on this and solution?
Melon. U refresh my brain. I made two amplifiers one raw allumium RCA ground was touching the ground it does not make the noise. Seems you give a vauluble point m second amplifiers I use proper box from Modushop. I think that RCA is not touchning the chasis. tmrw I will check that point. Highy appriciate ur feedback.
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