Althought « Audio et radio à tubes » is located in Cyprus. This is a french language youtube channel dedicated to designing tube /valve amplifiers. This channel covers different topics such as theory and practice concerning the valve / tube technology. This interview with sound engineer Mark Haliday covers some topics that are often counterintuitive for amp designers Adding distortion during recording with tube/ valve equipment, or with digital simulations reproducing the specific valves /tubes distortions. We also discuss the surprising return of analog tube /valve equipment to recording studios. Finally we evoke the new fashion consisting in removing tone controls or physiological correctors (such as « loudness ») on amplifiers. We sincerely thank Mr. Mark Haliday for the considerable time he kindly devoted to this interview, which was shot both in French and English.