Mullard 5-10

The Mullard 5-10 is a now famous mono hi-fi tube amp from 1954, with the then British tube manufacturers Mullard Ltd.. the high performance potential of his generation Noval tube EF86 and EL84 demonstrated. 5-10 The term was derived from the Tubes (5 tubes ) and the maximum achievable output power of the power amplifier of 10 watts.

The circuit design of the amplifier is in principle based on a development from 1947 of the English tube specialists DTN Williamson, who was also involved in the construction of KT66 beam tetrode: a precursor with an EF86 and a following phase inverter with an ECC83 drives two EL84 Endpentoden that emit in the push-pull principle, the power on the output transformer to the speakers. A small tube amp for distortion of 0.4 % at 10 W is achieved with a moderate negative feedback, for the rectification of the anode voltage is a two- tube diode EZ80 responsible.


  • The original article from the Practical Wireless Magazine
  • Description of the circuit design (English )
  • Amplifiers (audio)