Mate , 2 videos in 2 days and they"re great🥸

you're the hum master

Nice work! I always learn from your videos. Thank you

Thank you Stuart! I love viewing your videos and learn from you! 🤘🎩

Wonderful video! I'm getting better at diagnosis as I was dead on with this one. Thanks for the brain teaser.
Mike

Briiliant !  Who would ever come to this solution - great job !

Awesome. Thanks for the video!

I think they made loads and found out at some point about the hum, and thought oops, that's a costly fix but hey; why worry because if a musician plugs in a guitar and plays; he or she wouldn't necessarily hear the hum unless you were playing through the amp at low volumes..? Maybe..? Great remedy Stuart, you the man..Ed..uk..😎

god your good man

Good stuff!!

Great planning there at Marshall. Cheers

"ain't got no gas in it.."

..not sure if I know but I am sure you do thanks Professor...🇺🇲

Well done Stuart

Cool! I think my diy jtm 45 have same problem! I put metal palestine between transformers. Yes, less hum 20%. If I'm right, the output transformers have a magnetic field.

Brilliant video/ lesson thanks.

Yeah, I hope someone knows the story behind this baffling design fault and tells us in the comments! Thanks, for the heads up!

Very naughty of #marshall if it was a lack of caring and just getting them out the door for sale...

which year was it made?

3:45 I think standards have changed since that amp was initially designed in 1963. Some hum was normal and acceptable back then but today people will obsess about it. I'm assuming that's a re-issue model since it has a PCB. Newer generation of EEs probably are a bit ignorant about this sort of thing. If you've never scratch-built your own tube amp, you'll likely not know all of these little pitfalls because you never had to troubleshoot anything. I've scratch-built three tube amps. These days I think there is too much reliance on various technologies and that has these sorts of results.

It seems they were thinking the choke would be more of a problem than the PT. I noticed they 90 degrees originally.