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
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 .
This is why I have valves at home. I can at least change those out and see if that's the issue. I got a matched quad of Telam EL84s from a guy in Ukraine and a bunch of 12ax7's from a few stores in the US. I even have a couple of NOS vintage valves from GE and somewhere else. Sylvania? I don't recall ATM. I need to pick up some 6L6GC's so I have some of those onhand, as well. I got an incredible deal on those Telam. The Tube Store wants $80 for a single Telam EL84. I paid less than half of that. For FOUR(4) matched valves! 😁 Here's the best part. When I installed them into my amp, it didn't even need to be re-biased. Spec'd voltage was still within range. It didn't change and I'm certain I was testing at the correct location. They spec -12.5v and it was at -12.4v. Some of these amps, the Monoprice 15w aka Laney Cub 12R been found to be biased as high as -8.8v. The guy said he went through powet tubes pretty often.
Just FYI for the Origin series: for the fx loop to work, a TRS plug needs to be inserted into the foot switch jack with the ring open. Ring to ground turns the fx loop off and tip to ground turns the gain boost off.
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.'
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
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.
They kept failing on me and I got through about 6 of them! LAst time I went back to Eurotubes they had discontinued it and replaced it with these LED versions which I don;t like as mich.
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 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.
@@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.
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.
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?
Wow…I’ve been doing this kind of work for over 40 yrs. and this is definitely a first for me too Stuart. Fantastic video as always.
Interesting, I wasn;t aware that it was rare. Looking back through my records I notice I;ve had about 5 in over the years.
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
Thanks Mike
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 .
Thanks Tero.
I am a eurorack guy fascinated by your unique videos thanks Professor from Upstate New York..
Thanks Norm
This is why I have valves at home. I can at least change those out and see if that's the issue. I got a matched quad of Telam EL84s from a guy in Ukraine and a bunch of 12ax7's from a few stores in the US. I even have a couple of NOS vintage valves from GE and somewhere else. Sylvania? I don't recall ATM. I need to pick up some 6L6GC's so I have some of those onhand, as well.
I got an incredible deal on those Telam. The Tube Store wants $80 for a single Telam EL84. I paid less than half of that. For FOUR(4) matched valves! 😁
Here's the best part. When I installed them into my amp, it didn't even need to be re-biased. Spec'd voltage was still within range. It didn't change and I'm certain I was testing at the correct location. They spec -12.5v and it was at -12.4v. Some of these amps, the Monoprice 15w aka Laney Cub 12R been found to be biased as high as -8.8v. The guy said he went through powet tubes pretty often.
Interesting thanks for sharing.
Just FYI for the Origin series: for the fx loop to work, a TRS plug needs to be inserted into the foot switch jack with the ring open. Ring to ground turns the fx loop off and tip to ground turns the gain boost off.
Hi Jason. Ah, I didn;t know that thanks. The thing is, will I remember it in 5 years when I get another one of these???
That initial volume spike surly did wake you up! 😊
Sure did!
Oh, it was "surly" all right; churlish, peckish and peevish too! 😉
Young Stuart! THE MAN!
Thanks!
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. 😅
Interesting. I wonder what caused those heaters to go. Maybe the shock when they were still hot.
@@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.'
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
Cheers Steve
I almost bought one of these. May buy one next year for my bday.
Treat yourself!
I have had this issue usually with combo's. I reckon the reasonance from the speaker does them in. Especially if the owner thrashes it
Interesting thanks Steart
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.
Is checking the valves not the first thing to do , it’s generally the problem with a failure in a valve amp ?
Hi Paul. True, but I often get an instant theory about what something might be and pile into that!
Hey Stuart, one faulty valve but two..! Yeah that's odd..Still, a repair is a repair..Good Job..Ed..UK😃
Thanks Ed
Why have you different bias meters ? You had the LCD screen ones before ? Cheers
They kept failing on me and I got through about 6 of them! LAst time I went back to Eurotubes they had discontinued it and replaced it with these LED versions which I don;t like as mich.
Great Video! and learing experince may I ask what bias meters are you using I require something similiar for my tech work. Cheers Greg in Miami Beach.
Hi Gregory They are from Eurotubes. ABout $120 each from memory. Great meters.
April Fool's Special -- When a job comes in pre-sabotaged to test your honesty. Good Job, Stuart
Ah I never thought of that!
what is all that "buzzing"?!??
first thing I do when an amp comes in the door is test ALL of the tubes!
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
Thanks Steve several people were asking about the 'origin' of these amps!
As Little Walter (& JD Simo) sang 'Boom, Boom ...... Out Go The Lights'
Where can I get this schematic? I searched for quite awhile when working on mine, but could never find one.
Yes I couldn;t find it either.
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?
Yes but BOTH valve sockets?
@@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.
Those Eurotubes ones are pretty good I find.
Hi Stuart, maybe you should verify for oxidation on the power valves pins and tube sockets?
Good idea! See my reply to Steve above.
@@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!
@@goodun2974 Ugh okay thanks.
@@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.
Skip Simmons swears by cleaning valve pins with a light dab of WD40
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...
MAybe one went some time ago and he didn;t notice until the second one failed?
@@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.
@@VegasCyclingFreak Yes it will work, just slightly distorted.
GC has these on sale.
But, I think I'll stay away based on where it is made.
I've never seen that model either. Do you reckon it was released to the UK market only? I'm pleased the issue was easily corrected. Well done, Stuart.
Hi Alex I've seen a small handful over the years. Not sure when/where it was released. I'm reasonably sure they were British,.
Haha you never know what people do with their gear.
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?
Hi There's a splash screen at the end of each video which contains an email address. tx