Product was successfully added to your shopping cart.

Go to cart page

You have successfully subscribed to this product. You will receive an email when the product is in stock.

Telephone amplifier

Velleman K4900: Telephone Amplifier Kit

Velleman K4900

The Velleman K4900 Telephone Amplifier Kit (Electronic Project Kit -Soldering Required)

The Velleman K4900 Telephone Amplifier kit can be used as a stand-alone amplifier with a speaker to make your own speaker phone for your land line. Or, connect it to an amplifier or mixing panel. This kit is for use with land lines only. Telephone lines can have dangerous voltage levels, caution should be used when installing or using this kit.



  • Input: isolation transformer interface
  • Speaker output: 0.5W / 8ohm
  • Line output: 0dB (0.775Vrms)
  • Power supply: 7 - 9V AC or 9 - 12V DC / 150mA
  • PCB dimensions: 2.5 x 2.1"

Additional Information

Difficulty Level 2

Info Sheets

Resistor colour code

Connection diagram of the telephone amplifier build into a mixing panel (K2661 - K2662 - K2663)

Connection diagram of the telephone amplifier as stand alone unit.

Overview of Velleman modules that are equal to D.I.Y Kits
This sheet is useful when you want to know which modules you could find in the do-it-yourself range of Velleman Kits and minikits.

 Warning: this product can expose you to chemicals which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to: www.P65Warnings.ca.gov/product