Hello - build the K4102: led works. Sound: when I turn RV1 it goes from silent progressivly to hum. When I turn RV2 there is progressive noise but no signal from guitar. Same when headphone is plugged. Disconnecting IN cable produces sharp click/pop, typical sound you get when you pull jack out of IN of working amp (which I usually dont do btw) External connecting cables tested, they are ok. Any thoughts on what could be wrong? Thanks in advance.
Hello !
I assume, that you have a 1/4" jack plugged into the guitar, and a RCA plug into K4102.
But which type of cable are in between those 2 plugs, (screened or unscreened),
just in order to rule that possibility out ?
Thx for respons Brushless. OMG, now you mention it: i have a jack plug 3,5mm that receives my guitar cable and goes directly into the K4102, not an RCA plug… I’m gonna have to put a female jack to RCA cinch male in between… 
stupid me