Velleman K4001 7W Mono Audio Amplifier Kit

The kit arrived well packed. Clear instructions for assembly that were easy to follow. When assembled the amplifier worked perfectly. Good volume, I used it to amplify a DIY shortwave receiver.Definitely recommend this for anyone with basic solder skills.

Good quality kit. Extremely easy and simple to assemble. Good beginner kit for those learning to solder. Output level is loud and there is no distortion. The only reason why I didn't give it five stars is that there is noticeable background hiss when the volume control is turned down to minimal level. This made it no good for what I wanted to do which was to amplify an extension speaker for a two-way radio. Turning the volume to minimum to listen to other radios did not get rid of the annoying background hiss. I could find nothing wrong in assembly or kit components and powered both K4001 and its audio input source with batteries to eliminate any hissing or hum from AC powered supplies that switch or rectify DC out. Don't know if shielding is needed but instructions don't mention it.

Used as an external speaker amplifier for radio communications equipment. it works well. One side of the output is grounded so no issue, there. Good for mil radio sets that can't drive an 8 ohm speaker.

Very nice kit; easy to use instructions and the amplifier worked the first time! Good sounding little kit.

It was easy to solder everything and the documentation is thorough. It is not horribly powerful, but still impressive for its size.

Great little audio amp.