Fixing a Marshall Silver Jubilee 2550 That's Cutting Out | Tales From The Repair Bench
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- เผยแพร่เมื่อ 10 ก.ค. 2024
- Original Marshall Silver Jubilee 2550 head with no volume. Like many vintage amps coming in for repair, it's never just one thing so follow us down the rabbit hole as we give it a makeover for another 3 decades of action.
00:00 Initial inspection
06:00 Powering on & checking voltages
08:22 Signal testing
11:30 Talking about caps and replacing them
16:28 New tube socket time
18:14 Shielding V1 grids for lower noise
19:26 Turns out it was more than one socket
21:10 First audio test
22:14 Miced up playing demo
29:01 Final conclusions
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I have a Black face Deluxe Reverb that had this exact problem - random dropouts. It took around 14 months to finally get someone to clue into what it was. Unbelievable. Even then I had to coax them along and stamp "REPLACE THE VALVE SOCKETS!!" after having just about everything else done to it. The good news is that it now sings and is a solid unit. Of course, it also has ceramic valve sockets, but I could care less about "oh its vintage so it all has to stay the same" rubbish. If stuff is broke, it's got to be fixed/replaced. Parts don't last forever. Lots of fun watching your video though, as well as a certain level of anxiety. :)
I also have a 2550 Jube... serial number 0500 nonetheless! Love it to bits!
Nice work! Very thorough. Great to see it fit again and set for another 35 years.
There’s no good /bad quality solder wick. There’s just the brands that actually work and everything else. Love that stuff.
G'day mate, I'm a repairman down in Melbourne. Good to find your channel. You can never have enough knowledge, so thanks for posting. Cheers
Thanks. It’s always good to have others to reference and learn from and I’ve found no shortage of good ideas from other techs over the years.
Awesome job!
Great video!
Glad you enjoyed it
I had one with similar issues. The hi/low rocker switch had corrosion and one contact bent slightly. Easy to disassemble and repair these switches!
I have the 2555 100 watt version…I bought it brand new in 1987…Great amp…not my favorite Marshall ever made,but it is quite unique to the other Marshall’s of the day….The EQ especially..it actually works,Lol!
They use a very unique tone stack that affects frequencies in a totally different way to the standard passive stack that’s been around since the Tweed era.
I love your videos. Could you show us how you bias these amps sometimes?
Buen trabajo compañero. Pero, solo un apunte, aun se puede bajar el ruido del filamento . Solo hay que eliminar el bucle.
Saludos.
Thanks for sharing, I have one of these with the exact same issue of volume fading in and out from time to time. I've been meaning to take it apart and have a look, just as soon as I finish all the other amp projects I've got going on. Have you considered using a Haako desoldering tool instead of braid? I was hesitant to spend the money at first, but I bought an FR-301 and I'm glad I did. Makes short work of desoldering with less chance of damage.
I’ve been using a 701 station for years. Not every job calls for the desoldering gun and sometimes the heat sink effect of good solder braid is the best choice.
Whatever tool that is used is the one that will be best for the task at hand. If I’m recalling an old divide down organ or string machine, desoldering gun. Multi layer board with through hole plating? Gun.
nice
Man, you're treatin this tubes, especially the way you take out the power ones, like an elephant walks in a porcelain store. I would have waited something much more delicate from a "professional".
If you’re concerned with the abuse of tubes, might I suggest setting up a foundation that helps rescue poor bottles of glass from the overly rough treatment and abuse by horrible amp techs? You could have an ad that plays on TV with that Sarah MacLachlan song that’s in all of them.
@@drgearaustralia Heh
I have an original 1x12 Jubilee 2554 combo and had an issue where the sound kept cutting out. Patching the effects loop seemed to fix that problem but whilst playing on the drive channel, it will cut out from a distorted tone to a clean tone, in and out. Very annoying! The amp has been serviced multiple times and had renewed parts fitted but this issue still persists. Anyone else have this problem?
I happen to have a couple of old LCR Dual 50uF/500V DC Electrolytics that came out of a mate's JCM 800 (the one with reverb and two footswitchable channels), the date codes on them both read 89-21, one of them shows a distinct small bulge in the sealing bung, by my rough reckoning they are almost 30 years old by now, I read somewhere that most electrolytic caps have a useful lifespan of about 20 years before they need to be replaced, so I wouldn't put any trust in my two LCR caps.
Old caps, in the bin. Life span of most electrolytic caps at that voltage is around 10 years. Beyond that, the chances of spontaneous failure rise substantially. Those bulges indicate the caps are well past their best before and should be replaced.
I have a 1987 25/50 2550. I love it!! It really out shines other amps in a live setting. Thanks for the "amp porn"
I have the exact amp too!!! I'm in the process of overhauling it as well.
@@tomalcock620 yep, mine is getting recapped as we speak.
Quick question. at 1630 in the video on the tube socket you were drilling, were those little holes that are there already there, or did you drill them off screen? Also any idea why the tube socket on the far left has those screws and nuts but the other two don't?
The socket on the left has lost likely been replaced sometime in the distant past and they used screws to secure them instead of riveting them in. The socket on the right looks like it’s been riveted in the opposite direction. Either way, they all got removed and replaced with new nuts with locking washers.
Ohhhhh okay, that makes sense hah. Thanks man!
Do you remember what cab/speakers you used for the clip at the end? Tnx!
Just the test cab we have on the bench, an old Ibanez Tubescreamer TSA112 with a Celestion Seventy 80. Works fine for confirming output and whatnot and doesn’t sound the worst.
@@drgearaustralia thank you! I think it sounds quite good, actually. Great tones.
It’s less about the gear you got and more so about the technique behind it. I’ve done my share of recording previously in a professional setting so I have a simple setup for doing demos of the cab on the bench with a 57, nothing too crazy but it sounds ok.
@@drgearaustralia No doubt about that. I have a Jubilee myself and have tried quite a few speakers. Never would have thought a Seventy 80 could sound this good.
What would you do to this amp to make it more ballsy?? It already sounds good but a bit thin on the distortion department.👍👍
Hit the front end with an overdrive.
@@drgearaustralia I was thinking more along the lines of getting mine modded but I wouldn't even know if that's even a good idea.👍
I would like to see the inside of a Lerxst Omega. How it compares to this one.
The gut shots I’ve seen of them show a spaghetti mess of wires and a backward step in amp design over the original.
A well designed PCB for an amp like this is preferable to turret boards and techniques that were the norm in the 60s. High gain amps benefit greatly from well laid out, repeatable signal traces and proper grounding schematics. If you’re making a copy of an amp like this, I don’t know why you wouldn’t improve upon the design to make a lower noise floor, better usability and add some modern features
@@drgearaustralia I never heard anyone say they prefer PCB to a turret board. You are the first. You can do P-2-P without making a spaghetti mess.
I didn’t do an entire semester on pcb design and best practices in manufacturing to end up making products in a way that predates pocket calculators.
In one comment on a different video you say that no amp is worth that kind of money, yet on this one you espouse an incredibly labour intensive method of manufacturing that by itself very nature can’t be done at scale that would result in consistent quality and a low sticker price.
Even when I design and amp, it’s not done on a turret board, it’s done with custom fabbed PCBs with turrets that allow me to dial in circuits and change values and signal routing with ease. Others are free to do as they please, but I’ve got the skills and tools to make things with CAD and that’s what I was schooled with.
@@drgearaustralia Okay, you like to work in that environment, which is fine. It's what you know. Does it make a better amp in the end? Hard to say, but many PCB amps end up with burned traces and other problems in just a few short years. Some old amps are still being used today. Yes, all tube amps need maintenance, no matter how they are designed. And many people abuse these things, so they do not last long. But the very nature of a tube-amp is OLD technology. You are mixing old technology with modern design techniques. Which is fine. Current technology seems to be stuff like a AxeFX-III, or a QC. Power it however you want. Some people plug their QC into a tube power amp. Old school meets new school. So many options now. But most of this stuff is pretty expensive. Too much for the average player. I've been playing guitar for 30 years. I'm not that great at it. I use a Boss Katana head and an old Peavey 4x12 cab. Works great for me, and it wasn't expensive. I have a 50-watt tube amp, that was designed by Lee Jackson. It sits in my closet. I prefer to use my Katana.
I really don't understand why people replace a blown fuse with one that's rated too big for the job, I mean, how much is a fuse of the correct rating?, only something like 25 or 30 cents at the most?, I've seen examples where someone replaced a 2A fuse with a 10A one, and then they wondered why their expensive piece of music equipment is now an expensive smouldering mess.
The main reasons I’ve come across is ‘it’s just a fuse that keeps blowing but the amp works still, I’ll put a bigger one in’ or ‘I need to get through this thing and I’ve only got these larger ones available’ so they throw in whatever they have.
That’s why I want to try and educate people more about the gear they have to try and prevent major failures happening.
@@drgearaustralia I've seen the one where they wrap the blown fuse in tinfoil too, just to get things going.
the rhythm clip sounds like crap when used with the lead channel... its for the clean/rhythm channel
Tone is purely subjective my dude. That’s the best part about all the gear out there, it’s not one size fits all.