K4005b: high tone and smoke coming out of speaker

Kits Audio Hi Fi Projects
1

I’ve built the K4005B. when I tested the amplifier, I connected a 4 ohm speaker to the right terminal. I didn’t connect any audio signal.
When I powered it up, I heard a click, folowed by a constant high tone. I saw smoke coming out of my speaker.

I use all the suggested components for this kit. The K4006 for power and the 22530 as transformer.

What could be the problem?

2

Apparantly, due to an assembly or wiring problem, your amp is oscillating.
This can have different causes and it is hard to troubleshoot.
We suggest you return your amp for inspection/repair to:

Velleman Kit Tech Dept.
Legen Heirweg 33
9890 Gavere
Belgium

Do not return the power supply, only the amp.