Preamp hum problem somehow related to inputs

[arjscott]

Hi all,

I recent bought a preassembled Twisted Pear Kookaburra preamp from a friend and have just finished putting it in an enclosure.

It sounds fantastic and puts my current consumer hi-fi integrated amplifier to shame, even with the problem I've encountered.

I have to say I have very little knowledge of electronics, but you have to start somewhere, right?

Anyway, the problem is, at high volume a rather loud hum appears to be generated and can be heard from the speakers.

I found if I wave my fingers near the input RCA or cable it affects the sound of the hum significantly. And, if I place my finger over the end of the RCA, the hum stops.

Does anyone know what the problem is, and if so, how can I solve it?

Thanks in advance.

Andrew.

 

[v-bro]

Seems like there's a ground problem, how does it sound with the input unplugged?

 

[Leolabs]

Maybe bad contact regarding ground wire.

 

[Minion]

Yes, It sounds like the Ground (Maybe the ground on the RCA inputs/Outputs) as loose or not connected....

Try tieing the ground wire from the RCA to Ground....

 

[arjscott]

Thanks for the replies. Quite right - it seems one of the inputs was not gounded properly.

It seems so simple now

Andrew.