Marshall Origin 20 Guitar Amplifier It's Back!!!!!!!!!!!!!!!!!!!!
Вставка
- Опубліковано 1 жов 2024
- Marshall Origin 20 Guitar Amplifier back on the bench again just over a year later. It returns with another intermittent fault. Will it be a quick fix? Or will it be a nightmare to find this fault.
The designer does NOT know more than you. All your findings and suppositions re: 6V6s are correct. They also have 2W resistors dissipating more than 2W. Horrid insulting amps.
Hello Lyle, thank you. It starts out as a quick fix, then just goes pear shaped. I can't see the power transformer lasting long. I try to see good in everything. These amps look good on display but they are a Wolf in Sheep's clothing. Made to last few years then off to the landfill. Thank you for pointing out the 2 Watt resistors. The customer just wanted a quick fix. I didn't notice any baked resistors or I would have checked them. I don't do top side repairs though and the customer wouldn't have wanted to pay for the board being removed. Thanks for watching and take care Lyle.
Just as I marveled at the huge iron in the Burman 501, I am dumbfounded by that puny power transformer which looks like it would be at home in a 4W single ended amp. And EL34's? What were they thinking? On another note, it's always a joy to hear you play.
Hello Rico, thank you. Yes, a dreadful design all round. Take care.
Love your playing, and the repair part is always excellent and informative - keep doing what your doing 😊
Hello, thank you. Take care.
Why EL34 tubes? Because it's a Marshall and Marshall's must use EL34s - its BRITISH!
It's almost a Spinal Tap design. If only the volume control went to 11...
Great vid - now subscribed - keep 'em coming!
Hello Andrew, thank you. You could well be right. Thanks for watching and take care.
Have you ever converted any old 1950's P.As into guitar amps?.
I have a 1957 Newcomb E-10a in pristine condition.
It has all the original valves and hasn't been tampered with apart from the Mic plug being changed to a 1/4 inch jack.
It sounds really good but there's not much in the way of overdrive.
There's a schematic on the underside of the bottom plate.
Could you get it running like an old valco sounds?
Hello. Sorry for the late reply, I have been ill and I have got a bit behind with the comments. I haven't worked on any 50s PAs before. I am sure you could convert it to sound like a Valco if you had the right schematic. Are you in the UK? I don't see many 50s PA amps. There seems to be loads of them in the States. Thanks for watching and take care.
@vintageguitaramp_guitarteacher
Hiya, sorry to hear you where under the weather.
Yeah I'm in Glasgow.
It's true point to point with the circuit in pristine condition, I've read that a 5E3 type tone stack can be fitted without any trouble.
I'm sure someone as talented as yourself with amps could get it growling!.
It's got a beautiful clean tone and it does sound fantastic with a boost of drive pedal in front of it but the whole idea of getting an amp like this was to get away from pedals!.
Thanks mate.
Happy New Year.
Just a thought. In an amp that gets this hot wouldn't it be better to use some marine grade mastic instead of hot glue? Ðont mean to start controversy, sorry for my arrogance.
Hello. I welcome discussion on the channel so no problem at all. I have never used that type of glue. The problem with glue is that the next guy who fixes it needs to be able to remove it. I don't know how strong marine grade glues are. The glue has been brought up in the comments if you want to have a read. There will be a another video tomorrow on this, and some points raised on the biasing of the amp. Thanks for watching and take care.
You have to wonder how many of these will still be working in 10 or 20 years. It's a shame how cheaply they are built.
I just picked up an origin 50 . I plan on gutting it and building a jtm45 or something in it.
Great playing btw !
Hello. Yes, I was that wondering too. That's a great idea. The cabinets are pretty good and look the part. thanks for watching and take care.
"Planned obsolescence" comes to mind. If you try to use it, you can't use it, but if you don't try to use it, you still can't use it. Brilliant! (K)arl bros are cool \m/
That's a great analogy. Thanks for watching and take care.
Maybe a solution to the heat would be to fit a small 240VAC fan near the mains TX.. A pair of EL-34's would normally be associated with around 40+ watts output on a Marshall design amp, so I see what you're saying there Martyn. I can't get my head round that design concept at all, but it is what it is and is probably destined for the electronics recycling skip at the council dump in 10 years time. Another great net zero policy like battery powered motor vehicles eh !
A solution to the heat would be to spec the power transformer correctly in the first place. A fan wouldn’t help much without the surface area to dissipate heat. Maybe if you strapped aluminum heat sinks to the transformer or something….
I just wish Marshall would build a competent product.
@@matthewf1979, If somebody was insistent on continuing to use EL34's then I would probably add a 3 amp, 6 volt filament transformer to handle the 2.4 amp load of the EL34's. In addition to allowing the power transformer to run cooler, this might slightly boost the B+ voltage and available current from the power tranny, which means perhaps you could bias the tubes a little hotter.
Hello Pete. I don't think a fan work as the transformer is getting hot deep inside the wingdings. It might make a little difference but not enough to save it long term. Take care Pete.
Agreed Matt. A bigger transformer should have been bolted on to this thing. Or just 6V6 tubes. Take care Matt.
Hello Pete. I don't think a fan work as the transformer is getting hot deep inside the wingdings. It might make a little difference but not enough to save it long term. Take care Pete.
It's a shame one can't use a fan like car audio too Cool the amplifier down..
Hello Jean. The problem is that the transformer is getting inside the winding's. I don't think a fan would cool it, even if one could be fitted. Thanks for watching and take care.
At least the EL34s should last well, even if the power transformer fries.
Hello Steve. That's true. It will fry at some point though. Thanks for watching and take care.
The guy at Headfirst Amplification knows that amplifier well I’ll see if I can find his UA-cam channel and post it for you my friend. Awesome playing as always.
ua-cam.com/video/Q_hiXjOS1Y8/v-deo.htmlsi=y6GklgHLK0uXHF0_
Hello David, thank you. Take care.
Thanks David. I will check Headfirst out. Take care.
Hmmm. Dual EL34 tubes. Positioned upside down. Heat flowing UP into the circuit board. Intermittent failure after moderate on-time? Seems like Marshall learned nothing since 1997 when they had the same problem with the JTM-60 series that had the same problem. I have a JTM-60 head that is currently dead for similar reasons. When it dies, sound fades out in about 4 seconds without any dramatic pop, thump or BZZZT noise. Nothing inside looks burnt / fried. There's just something under-spec'ed that routinely fails. Mine has failed the same way about 5 times since 1997. Frustrating. The amp SOUNDS great... When it works.
Hello. Yes I remember some of the problems with the JTM60s. I have worked on the 30s but not the 60s. There is a two part video on the channel on the JTM 30. I have put the links below. Thanks for watching and take care.
ua-cam.com/video/WmpqOu1zoBQ/v-deo.html: Part 1
ua-cam.com/video/3xAboK_Zdg8/v-deo.html: Part2
When you were measuring the plate voltage and doing the bias calculations, did you have the amp set to the high power setting? At 10:26 in the video, it looks like the switch was set to the middle power setting. I have a Twin Reverb amp that has been modified (not by me) to have a half power switch installed (achieved by using a voltage divider). When on half power, I am only measuring 254 volts on the plates, while on full power I measure 510 volts. Of course the plate current differs also. My amp is not cathode biased and uses 4 6L6's, but I thought perhaps the Marshall was using a similar setup to achieve the lower output.
I also have a Sovtek Tube Midget that has a similar tube compliment (3 12AX7's and 2 6L6GC's) and it is rated at 50 Watts. My plate voltage on the 6L6's is 499 and 498 volts (also an adjustable fixed bias amp), so different from the Marshall.
Hello Michael. I looked back at the video. It looked like it was set to high. I am going to do another video on the bias as I could have made a mistake. Someone else has also pointed this out, so we need to clear it up. The watcher that also brought this up would like to know the bias readings in all three settings. That's what I should have done in the first place. So it will be good to know all the readings. I couldn't find a schematic for the amp so I don't even know how the three power settings work. It could be the same as yours. We shall find out tomorrow hopefully. Take care Michael.
Thanks for posting. Why test the dissipation at mid or low power settings? Do you know that the B+ is lowered to achieve the 3 watt mid power setting and the .5 watt low power setting? 254vdc indicates less than full power mode IMO. In part of the video I see the switch in the mid position also. You used hot glue after stating that the amp gets very hot. I have seen hot melt glue that puddled and self leveled while spreading out on the chassis due to repeated heating over time in tube amps. Tasty playing by the way. Anyway. How many watts are the EL34 tubes sitting at in high power mode? What is the B+ in high, mid and low power mode?
Hello. I looked back at the video and the switch looks set to high. Someone else has mentioned this in the comments also. I will do another video on this to clear it up. I could have made a mistake and also, you have raised a good point about the three settings low, mid, high; a different plate voltage for each setting? Let's check it.
The hot glue. That did cross my mind. But the board is not getting hot enough to melt it. I buttoned the amp up and had it on test for a couple of hours. Then dropped the chassis out just to have a check round that everything was fine. The board was no more than warm. The transformer gets hot that's for sure.
Some techs get a bit stroppy with things being pointed out in the comments. I don't. The viewers keep me on my toes and I welcome discussion on the channel.
Thanks for watching and take care.
My silly guess is that Marshall knows how fickle guitarists can be about certain components and worried that it would be hard to sell a Marshall amp without EL84s. They prefer to sell a poor design as long as it has the “proper” tubes for a Marshall amp on the specs list.
I have a DSL5, and haven’t heard or read anything bad about the 5 watters. Also have heard a lot of good about the 40 and 50 watt models. I’ve heard bad stuff about the 20 watters though and wonder if it comes down to a silly tube choice
Hello. Some good points there. The shop I worked at years ago had the Marshall dealership and I do remember the DSL 20 was not a good seller. I have never worked on any of the DSL range. They would an interesting video though. Thanks for watching and take care.
the famous pcb £400 market...speakers decent, and cab looks good...competition forces cuts on all the major brands on these...buyers dont look at xformers they look at amount knobs it has and an aux lead..
Hello, yep, you are spot on there. Thanks for watching and take care.
I saw 3 of these (head version) in the used section of my local guitar center. I said to myself, “They must be garbage.” 😂
Hello Cole. That's where most of them will be heading to in a few years. It's just marketing. Thanks for watching and take care.
Its amazing how the big companies have such a stronghold on the market that let them get by producing garbage. Time after time and yet guitar channels keep raving about them. Lovely playing as usual, its the cherry on the cake!
Hello, thank you. That's true It's like most things manufactured today. They are made to throw away. Thanks for watching and take care.
😄😎
Thank you. Take care.
I suspect the 'designer' thought that EL34s would last longer, but forgot that big boys eat more
Ha Ha. That made me burst at the seams when I read that. Thanks for watching and take care.
The amp sounds good, so does your playing. I would enjoy seeing that amp fixed with your ideas.
Hello Barry, thank you. Yes, it would be good to get one and mod it. Thanks for watching and take care.
yeah it gets to where if you want an amp done right you have to do it yourself or if you're lazy like me find an amp builder enthusiast and pick up a nice one when he gets more amps than his missus will allow and has to sell a few off hahaha lovely playing as always, did i detect a little triadic idea in there? whatever it was it sounded lovely. your time feel was superb in there at times as well.
Hello. Yes, always better hand built. Yes, there was a few triad ideas floating around in that jingle. Thanks for watching and take care.
Another brilliant video. I enjoy both the tech part and your superb guitar playing.
Hello Michael, thank you. Take care.
Sweet playing dude 😊
Hello, thank you. Take care.