When the power line fights your amp - Hidden problems in 1960s hi-fi power supplies

Video Description

In the early days of hi-fi, even the electricity from your wall socket could shape the sound of your music. In this video, I explore a fascinating 1965 Audio magazine article by George Lehsten, Chief Engineer at Alpine Geophysical Associates, Norwood, NJ. Lehsten investigated how everyday variations in mains voltage could affect amplifier performance—especially in the bass. I’ll look at how 1960s tube and early transistor amplifiers depended directly on the household power line, how voltage dips could cause sagging bass and distortion, and how engineers learned to tame those effects through better power-supply design and regulation. You’ll see why a 10% drop in voltage could mean a 25% loss in bass power, and how these early challenges led to the stable, powerful amplifiers we take for granted today. Mentioned in this video: 📖 George Lehsten, “Effects of Power Line Variation on Low-Frequency Operation of Amplifiers,” Audio magazine, February 1965 If you love vintage hi-fi, audio history, or classic engineering stories, don’t forget to like, subscribe, and share! Got memories or corrections from the golden age of hi-fi? Leave them in the comments - your insights help keep this history alive. THANKS TO: Gary Alan Henson for his assistance with this video. EQUIPMENT USED TO MAKE AUDIO MASTERCLASS VIDEOS CAMERA - Sony Alpha A6600 https://amzn.to/3uj7Dtq COMPUTER - Apple Mac Mini M2 Pro https://amzn.to/47tW6Wg MICROPHONE - Sennheiser MKH 416 https://amzn.to/3QWWvuO ALTERNATIVE MICROPHONE - AKG C414 https://amzn.to/3SLqCad BUDGET MICROPHONE CHOICE - Rode shotgun https://amzn.to/3G0ni36 MICROPHONE PREAMPLIFIER - Comica LinkFlex AD2 https://amzn.to/40SMHFT TELEPROMPTER - Padcaster Parrot alternatives https://amzn.to/40A55TJ TELEPROMPTER SOFTWARE - PromptSmart Pro https://promptsmart.com/ AUDIO INTERFACE - Behringer UMC202HD https://amzn.to/3ugj6db HEADPHONES - Sony wired https://amzn.to/3sEjlht SPEAKER CABLE - KabelDirekt https://amzn.to/3ucgQ6T POWER AMPLIFIER - Fosi V3 https://amzn.to/3vRumNH KEYLIGHT- Amaran 100d https://amzn.to/40A5Gor FILL LIGHTS - Switti RGB https://amzn.to/3ufhOPu SOFTBOX Phot-R alternatives https://amzn.to/3QGoTjJ LIGHTING STANDS Phot-R alternatives https://amzn.to/3QWXOKe MONITOR - Samsung UJ59 https://amzn.to/3MEoBsk MONITOR ARM - Invision alternatives https://amzn.to/40SLqi5 MIC ARM - Yellowtech M!ka (10% discount) - https://shop.yellowtec.com/discount/AUDIO-DAVID TRIPOD - Velbon alternatives https://amzn.to/46gu2oa GREEN SCREEN - Elgato alternatives https://amzn.to/3SG2F3L DESK - FlexiSpot E7 Pro https://amzn.to/3QVIWvS ERGONOMIC CHAIR - FlexiSpot C7 Air Pro https://www.flexispot.com/flexispot-best-ergonomic-office-chair-c7 VIDEO EDITING - Apple Final Cut Pro https://www.apple.com/final-cut-pro/ IMAGE EDITING - Adobe Photoshop https://amzn.to/3FZ7Ww0 AUDIO EDITING - Avid Pro Tools https://amzn.to/3QA5Wz7 NOTEBOOK - Leuchturm 1917 hardback https://amzn.to/47zonKX PEN - Sakura Pigma archival pen Sakura Pigma archival pen https://amzn.to/47zz3cP OSCILLOSCOPE - Hameg HM 203 alternatives https://amzn.to/47tWN1O GROOMING - Philips 3000 nose hair trimmer https://amzn.to/40BdLJo GROOMING - Nose plier https://amzn.to/41IOZaR HAIR COLOUR - Just For Men https://amzn.to/475OgS1 HAIR CONDITIONER - TRESemmé Silky & Smooth https://amzn.to/41AdWFd OPTICAL AID - https://www.tigerspecs.co.uk/item/jelli-multi-coloured-reading-glasses Disclaimer: Videos on this channel may include affiliate links and may feature software that has been received free of charge with an NFR (not for resale) licence, equipment that has been loaned or donated by a manufacturer or distributer, or equipment that has been bought for less than full retail price.