Help me please: my JFET-based circuits hums!

[Unkn0wn Art1st]

I built a few circuits where JFETs need biasing (ROG's Eighteen, Thor, Condor etc), and all of them hums
I use soviet transistors КП303 instead of J201, maybe it's their guilt? But when I put it into mu-amp, they work pretty good
When I adjust 4.5 V at drain, a low hum appears together with a sound. And when I increase voltage, sound disappears, and a hum remains.
What's the deal?

[R.G.]

I built a few circuits where JFETs need biasing (ROG's Eighteen, Thor, Condor etc), and all of them hums
I use soviet transistors КП303 instead of J201, maybe it's their guilt? But when I put it into mu-amp, they work pretty good
When I adjust 4.5 V at drain, a low hum appears together with a sound. And when I increase voltage, sound disappears, and a hum remains.
What's the deal?

Are you using a power adapter or batteries for powering the circuit?

[Unkn0wn Art1st]

I use a adapter. I'll try to use batteries,maybe this can help, thanks! I'll make it tomorrow.

[Unkn0wn Art1st]

I connect a battery to my circuit and hum's gone thank you R.G. !!!!!!!!!!!!!
it means my adapter sucks but it's a useful bipolar power supply with adjustable voltage up to +/-16 V, I don't want leave it

[R.G.]

I connect a battery to my circuit and hum's gone thank you R.G. !!!!!!!!!!!!!
it means my adapter sucks but it's a useful bipolar power supply with adjustable voltage up to +/-16 V, I don't want leave it

I know what you mean. I had a girlfriend like that once. 

[Wild E]

Not too useful as it is if it hums! I have a wallwart that hums too. I wanted to dedicate a box to it so I built a filter circuit onto the power input jack. Now it only has a little at max vol.
Read this thread http://www.diystompboxes.com/smfforum/index.php?topic=80063.0
lots of good info there.

[Unkn0wn Art1st]

I know what you mean. I had a girlfriend like that once. 

Not too useful as it is if it hums! I have a wallwart that hums too. I wanted to dedicate a box to it so I built a filter circuit onto the power input jack. Now it only has a little at max vol.
Read this thread http://www.diystompboxes.com/smfforum/index.php?topic=80063.0
lots of good info there.

I had an idea to insert some filter inside my stompbox, thanks for the link!

[FiveseveN]

I had a girlfriend like that once

You had a girlfriend with adjustable voltage  

Unkn0wn Art1st: building a regulated PSU is really simple and well worth it.

[Unkn0wn Art1st]

Probably I can modify my own adapter...

[Kain]

I had a girlfriend like that once

You had a girlfriend with adjustable voltage  

Maybe he meant that she sucked, but he didn't want to leave her?

[Zapp Brannigan]

I built a few circuits where JFETs need biasing (ROG's Eighteen, Thor, Condor etc), and all of them hums
I use soviet transistors КП303 instead of J201, maybe it's their guilt? But when I put it into mu-amp, they work pretty good
When I adjust 4.5 V at drain, a low hum appears together with a sound. And when I increase voltage, sound disappears, and a hum remains.
What's the deal?

КП303 has a ground lead, it is the 1st one from the mark, may be you didn't solder it to pcb ground trace?

[Unkn0wn Art1st]

КП303 has a ground lead, it is the 1st one from the mark, may be you didn't solder it to pcb ground trace?

I soldered it to ground, it helped to reduce the noise and whistles only, not hum. It turns out that my crappy PSU produces this hum
You are so well acquainted with Russian transistors, where do you live?

[Zapp Brannigan]

КП303 has a ground lead, it is the 1st one from the mark, may be you didn't solder it to pcb ground trace?

I soldered it to ground, it helped to reduce the noise and whistles only, not hum. It turns out that my crappy PSU produces this hum
You are so well acquainted with Russian transistors, where do you live?

Moscow, Russia.

[Unkn0wn Art1st]

Moscow, Russia.

I'm from Ukraine and don't speak English it's a miracle that dudes understand me