Great video. Really refreshing to watch professional working without any music or special effects. Easy to understand what is goingb on even I’m not electrical edjucated .
Stuart, It's always exciting to see a new video from you. I find it fascinating as you go through the troubleshooting process. Thanks for talking through it. Mike
Hi Stuart great to see you work as always, Its been a while since i was drinking tea with you in that workshop of yours. Also great to see those Ambersil products being used i can get them here in Aus but financially prohibitive unfortunately, i reckon Amberclens is the best Tolex cleaner ever invented. great fault finding as always. cheers for now, lets catch up in Caversham next time im in Blighty
That was an interesting one Stuart.. Several years ago I had a Marshall JCM-800 1X12 50 watt combo. I switched it off after the gig ended and our drummer managed to walk into it seconds later carrying his kick-drum and the amp fell over on it's front. Not much of a fall as they go, but when I turned it on at our next rehearsal.. Nothing.. You've guessed it.. Both EL34's not even showing the glow from the heater element. That's the only time I've heard of both output valves going tits-up at once.. Drummers.. Can't live with them, can't live without them. 😅
@@stuartukguitarampguy5830 Yes.. I think the valves were still quite hot and I remember someone saying a few years ago, 'always let your amp cool down for at least five minuets before moving it as the valves are most vulnerable when at, or near, working temperature.'
Marshall released the Origin 50 in 2018 so not so surprising that tubes have failed when they could have 6 years of use. The Origin models don't have a great reputation
I had the same problem. I swapped out the tubes and have run the amp about 6 hours every day cranked (I have an attenuator) for 3 years without any problems at all. I love the amp though i wish they left out all the nonsense and made a basic JCM 50. The goofy power cuts sound like garbage. With all their faults an attenuator sounds much better. I bought my first Marshall a 1987 in 71.
I purchased of ebay 2 EL34'S they lit up my valve tester but putting them in my amp failed to lite up must have been a different pin size. I wonder is the valve socket?
@@stuartukguitarampguy5830 Yes both valve sockets in may Blackstar 40 watt combo did not work with the valves from ebay I cant remember the brand but I think they where British made different pin size maybe? but the one's that came with the amp did and they are EL34 BHT, Chinese which has much larger anodes than normal EL34'S May be when you where testing the amp and as the valves heated up it caused a issue with the valve sockets ??
Interesting. I have the habit of testing all the tubes on my auto-tester before starting, just to make life easier. I built my own Bias meters, because nobody made one I liked.
That's a very interesting failure mode. I wonder if something else made those tubes fail and it might happen again sometime down the road. I guess time will tell...
@@stuartukguitarampguy5830 If it's a two power tube push-pull circuit, one power tube is taking neg half of the cycle and the other one taking pos half of the cycle. I don't know that it would work on just one power tube. Never have tried that to see what happens.
@@VegasCyclingFreakThe amp will still produce sound at a fairly decent volume. There’s tons of distortion though. I can see how someone could miss it at bedroom levels with the gain cranked or using pedals.
@@matthewf1979 Could be the case... but I wonder how the tubes failed in the first place. I suppose it could have been a defective batch of tubes. Also weird that no current flowing... suggests perhaps an open connection inside.
@@stuartukguitarampguy5830, Check the soldering on the EL34 tube pins as well ---- I've seen modern Russian and Chinese tubes where the leadfree soldering in the tube pins was intermittent!
@@stuartukguitarampguy5830 , It's also possible that a weld let go inside the tube where the pins connect to the individual elements but that isn't something you can repair. Bad soldering on the bottom of the EL34 pins is easy enough to fix.
Hi Stuart, I would like to consult you about a problem I am having with my Harman Kardon avr amplifier. Do you have an e-mail address or social media account where I can reach you?
