I don’t think that that would get rid of common mode noise. But my filter is implemented like that - a capacitance multiplier followed by plenty of bulk and high frequency filter caps - a mix of 470u electrolytics, 1u films and 100n ceramics
Remove the wire going to the guitar and see what happens.
Maybe the earth / shield is damaged, and the wire is inducing noise.
Maybe the earth / shield is damaged, and the wire is inducing noise.
This choke should block frequencies down to 100Hz and provide an impedance far above 1MOhm. Obviously there a no chokes available to suppress this kind of low frequency cm noise - it is a dead and street. And ferrites block frequencies in the MHz-range. Even the old mains xformer PSU introduce some kind of this noise, but to a lower degree. The problem is known for decades and for that reason you will find no serious guitar amp with a 2-prong mains plug.
So, did you check grounding your amp meanwhile?
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Try searching for old car amps at a breaking yard
But a power supply will be needed.
Try for old mains operated amps on online flea markets...or yard sales, whatever.
But a power supply will be needed.
Try for old mains operated amps on online flea markets...or yard sales, whatever.
Basically non-grounded energy.
Happens a lot on computers
And if your desktop is not grounded, the hard disk has a tendency to build up static energy, and flash over, can fry it.
So use a ground cable, or put the thing in a metal cabinet of some sort, and earth that.
Laptop earthing is something I haven't thought much about, I prefer desktops with large screens.
Try this, if you can't earth the amp as such...put it in a shielded enclosure, like an old computer cabinet. And connect that to earth.
When you touch it, you are providing an earth path.
Same principle as a neon line tester.
That tiny amount of stray energy gets amplified, and when you touch it, it finds an earth path, and the hum goes away.
Try barefoot if you feel adventurous!
Happens a lot on computers
And if your desktop is not grounded, the hard disk has a tendency to build up static energy, and flash over, can fry it.
So use a ground cable, or put the thing in a metal cabinet of some sort, and earth that.
Laptop earthing is something I haven't thought much about, I prefer desktops with large screens.
Try this, if you can't earth the amp as such...put it in a shielded enclosure, like an old computer cabinet. And connect that to earth.
When you touch it, you are providing an earth path.
Same principle as a neon line tester.
That tiny amount of stray energy gets amplified, and when you touch it, it finds an earth path, and the hum goes away.
Try barefoot if you feel adventurous!
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Frankly, you lost all credibility to me when you said all pro guitar amps in the world have a 3 prong plug.
I can tell you that I investigated this effect in depth for the company I was working at as hardware designer. So I can reassure that your assumption with RF-noise is of little credibility. Among other I play the electric guitar on stage for 5 decades now and can not remember any amp with a 2-prong mains plug. So feel free to name me some serious guitar amps that use a 2 prong mains plug😉
I didn't since one of the posts mentioned it could cause faults in the adapter, and I don't want to risk a fire. I doubt the safety precaution taken while manufacturing were up to standards.
However I did try a laptop charger with a three prong plug - I hear the noise all the same. I did discover something though - If I leave the charger connected to the amp, but switch the charger off at the outlet, I still hear the noise even with batteries powering the circuit.
I'm always barefoot at home, no carpets no nothing. Saves me the trouble of having to worry about frying electronic components in my modest lab
How did you switch it off? Did you remove the plug?
Btw - which posts mentioned it is dangerous to ground the adapter? Any adapter MUST BE SAFE in that case-
otherwise it is UNSAFE! period.
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I switched it off by just turning the switch off. The plug was still plugged in. As for the post on faults -
Ready amp and FM/SD/USB module.
2.1 Amp, 3 x 2030, 2 US Dollars.
FM module 1.5 Dollars
Transformer, 12-0-12, 3 Amps, extra.
Okay for small rooms.
2.1 Amp, 3 x 2030, 2 US Dollars.
FM module 1.5 Dollars
Transformer, 12-0-12, 3 Amps, extra.
Okay for small rooms.
Attachments
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This uses a 4558 to filter out bass and drive a woofer, I am going to put a 4 inch one.
Oh, and the pots are extra, wires come with the kit, there is a 7805 to supply the module.
There is a Keltron capacitor version for about double the price, this has cheap Chinese ones.
But for about 6 to 10 dollars, can't really be fussy.
Oh, and the pots are extra, wires come with the kit, there is a 7805 to supply the module.
There is a Keltron capacitor version for about double the price, this has cheap Chinese ones.
But for about 6 to 10 dollars, can't really be fussy.