my gainclone is humming

[fezz]

ive just finnished my test gainclone.


turning it on reviles a very loud hum. it does play music but adjusting the 100k pot does not effect anything, i am wondering if this could be the problem, but i doubt it is the course of the humm... i also do not think it is ocillating as there is almost no heat comming from the heatsinks (wich are quite big)

any ideas?

 

[jam]

Maybe it forgot the words?

Fezz,

Sounds that you have a ground problem. Check to see that all you grounds are hooked up correctly.

Jam

 

[Mad_K]

It is most probably improper grounding.. Try to give all ground points a separate wire to your star ground.

 

[fezz]

thats one thing i have paid alot of attention to.

i have star ground - almost all of the components have individual ground wires. however i will re do it in the moring.

i have removed the volume control and input capacitor as i have low DC (o.o3v)

i also do not think it is the transformer

some interesting things though:

when i put my hand on my walkman (using as source) the humm gets louder

then i put my hand on the heatsink the humm gets quiter

 

[Mad_K]

Are the heatsinks grounded?

 

[EchoWars]

my gainclone is humming

Perhaps it doesn't know the words...

(apologies...but someone had to say it).

 

[TjongKristian]

Try

I had the same problem before, what I did was seperating the input ground from the star ground.

 

[fezz]

well....

i removed the 100k pot from the input and put a 47k resistor to ground, followed by a 10k resistor, the hum went.

when i tried to pt the pot back in, the hmm came back

the heatsink WAS grounded, bt it didn't do anything, i will try removing the input from the star ground in a bit.

to be honest i belive all it needs is a good case, as all of it is open right now