Marshall JTM 30 Guitar Amplifier Three Faults and Counting Repair and Demo
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- Опубліковано 1 жов 2024
- Marshall JTM 30 combo tube amplifier with three faults and counting. We try and get this guitar amp running and look at some of the pit falls of PCB amplifiers.
Nice video with some good playing by you. Good !
Hello Dave, thank you. Thanks for watching and take care.
From what I heard many have switched the valves from the 5881 to 6l6. I’m no guitar tech but I got mine for $345 tax in Canadian about 15 years ago and much later found out the tubes were rca blackplate 6l6gc. Worth the price mine has never had any issues so either someone who knew amps had it fixed or I’m luckier than any other jtm30 owner. Mine is the 1x12 vintage 30
Hello. Nice tubes are those RCAs. I had two JTM 30s when they came out. One i never had a problem with in three years and the other was a pain. You must have a good one there. I will do a bit of reading up about the valve swap, that's interesting. Thanks for watching and take care
I'm a bit late to the party but I own two JTM30's one I bought new and one I got used.
The nuts have not gone missing Marshall never put them on both mine only have 3 nuts. Probably saved them 20p per amp.
The JTM I bought used I recapped due to leakages about 5 years ago.
The only issue I found is you have to ensure the effects loop sockets are cleaned regularly.
I'm still running the original Sovtek 5881's, they do run a little hot but I've had no issues.
I do like a video showing what previous repairs/bodges have been done.
Thank you for sharing
Hello Keith, thank you. I bought two of them when they came. out. That explains the nuts, thank you. It's amazing how long tubes will last in some amps. These amps are coming up to 30 years old. They did have a bad batch of transformers when they first came out. They are not a bad little amp for gigging. Not to heavy either. I have a 2 x 10 one at the moment that just needs a quick service. Just need to find time in between customer repairs to fix it.
Thanks for watching and take care.
Bought a used jtm 60, the heat melted the plastic preamp sockets and the effects loop had intermittent issues,and the board traces came off,so after working on it I sold it for parts.
bought one new in 95, played it a bit back in the day in my room, than it sat for years unused as I moved out from my parents place. Started playing again in 2005, but never an awfull lot. One power tube got microfonic. It burnd the power transformer, and afterwards the output transormer. Nice sound, but a pain in the ass amp quality wise. 480v on the plates, way too hot for layed down valve contruction. Instal a fan if you have one to cool things down.
Hello. A lot of people have had the overheating troubles. This one din't seem to be running hot. The 60 watt version is the worst. They run really hot. The problem with these amps is the power transformers are underrated. Thanks for watching and take care.
I wish I was that ‘rusty’ on guitar 😅
Great video, I had one of these as my first valve, broke down on a gig and was always having issues after that. Got it fixed and sold it and I think it was fine after that, just my luck!
I used to really like the clean channel.
Hello Mark. I had one from new. Mine was fine. I worked in a music shop at the time. We had a few of them back in with problems. The biggest problem was a batch of bad power transformers. I gigged mine for three years. Thanks for watching and take care.
wow! finally someone beeing actually able to play playing this, great sound! xcept for mr segborn… all other players demoing this amp close to abysimal… exchange that pot and be done with it. cheers!
Hello. I gigged one of these amps for three years. I had one new when they first came out. Some of them had problems with the power transformer blowing. Mine was fine. It was a decent amp. I have bought another one. You can pick them fairly cheap now if they have faults. The one I have just bought has the same fault, dry joints on the pots. These amps are nearly 30 years old now and still going strong. Thanks for watching and take care.
@@vintageguitaramp_guitarteacher my first amp i ever played on a rehearsal was a jtm60... couldnt take advantage of it though...noob. i liked the 15inch. right now i´m eying a used jtm 30 asking price 150€ owner says it drops out for some time during rehearsal... sounds like it could be overheating issue... i have some diy skills for switching caps, instaslling heatshield, modyfying the bias diodes... but am worried output transformer could be damaged from overheating. is it a steal or a potential heap of electronic scrap? whatya think?
I have the same amp. Replaced the power transformer because over heating blew it. I found out that it was the 5881’s that were drawing too much current. I put 6L6’s in there which run cooler and added a cooing fan for kicks. It’s funny because my pots only have a couple of nuts. My old tech took them off years ago for a reason and I can’t remember what that was and he is not available anymore to ask. Nice video, thanks!
Hello. That's interesting. Some did seem to hot and some didn't. Maybe they upgraded the power transformers at some time during production. Or maybe they changed to 6L6 tubes as you have done, or re-biased the 5881's for less current. I will do some tests if I get another one in for repair. Thanks for watching and supporting. Take care.
Does anyone know if these amps break down easily? It seems like they do.
Hello. The 30s are relaible. They do sometimes suffer from dry joints on the pots though but it's an easy fix. Thanks for watching and take care.
Different amp, but I got hold of a Marshall lead 12 for peanuts as it had intermittent output. The issue was them bleedin nuts on the pots. The volume pot didn’t have the internal nut, just the outer and it had been pulled forward whilst being used and it had broken the solder. Daft design really.
I’ve been offered a JTM30 that has intermittent sound issues for pretty cheap. Maybe worth a punt for £50? I’ve a lot of experience with flexi PCBs (years of line 6 home repairs) so that doesn’t scare me as such.
Very informative video. Thanks for making and sharing.
Hello Andy. thank you.. 50 quid is well cheap for JTM30. It shouldn't be to much trouble to fix it. The lead 12s are getting quite rare now. They are good amps. Thanks for watching and take care.
Love mine. Had it since new though it spent a long time not really used. Then got back into playing. Its had a new power tx. Also had it repaired once as volume was fading in and out. Think they replaced a jack and one or two pots. Used to find it a bit harsh though and recently fitted a creamback which really helped. At the same time did the recommended bias diode change by replacing 9v to 12v I think and added washers under the mount screws to help cooling. Sounds GREAT. only issue now is after that fading reapir, the red channel is very quiet compared to the clean channel. I'd like to sort that. ANy ideas what that may be and could I bring it to you?
Hello, sorry for the late reply. Not sure what that could be. I could take a look. I am based in Nottinghamshire, if that's not far for you. Thanks for watching and take care.
I bought one for $700AUSD but at first the shop had $1400 on it so knowing that they were prone for disaster I waited and waited until they dropped the price. Nowadays I've gone acoustic so it's sitting in my studio gathering dust. They sound so good
Sounds like you got a half price bargain there. Yes they don't bad at all for the money. Thanks for watching and take care.
Have one of these! Trashy cabinet got trashed and I built a new one for it. Other than wimpy reverb I have never had any issues.
Hell Rich. I had one years ago and gigged it for three years. It never missed a beat. But others that had them had problems. Looks like we were both lucky with ours. The reverb tanks are a bit on the small side. Thanks for watching and supporting. Take care.
I think that's the first time I've heard you play hi-gain stuff. I like it. Pat test comment made me laugh too... cheers.
Thank you. Yes, it's been a while since we had some hi gain on the channel. Ah the PAT test🤣
Subtitles plis. Thank you.
Hola Miguel. He agregado español para los subtítulos. Si esto no es correcto, por favor hágamelo saber. Comenzaré a agregar español a mis otros videos durante la próxima semana. Lo siento y gracias por señalar esto. Cuídate.
@@vintageguitaramp_guitarteacher Hello. Thanks a lot.
The 1x 15 was the best model. Didn't suffer from overheating due to the size of the cabinet. I had a couple. Bit fizzy sounding but good value now used.
Hell Ricard, Ah yes, I had forgotten about the 1 x 15, which is a bit of a slap on the wrist for me as I worked in a music shop in the late 90s and we had the Marshall dealership when the JTM range came out. Thanks for reminding me. Thanks for watching and take care.
Never heard of a 1x15? Research time!
Mine gets so hot you can fry an egg on it, it has melted some of the plastic on the back do you know of a way to maybe hook computer fan and mount it on one of those?
The playing at the end of the video was good! Any help is appreciated from the states thank you..
Hello, thank you. If it is getting that hot it might need the bias circuit looking at. Do you have a tech living close by that could check for you?
Yeah, venting the valve heat into the chassis was unsmart of Marshall. My tech fitted a shield to stop that nonsense, but the better course might be to vent the top of the cabinet, AC30 style, or as you say, fit a fan (shudder).
I love the JTM30! I’ve had three of them, still have 2. Fantastic sleeper amp. Clean channel is revered, but I actually like the drive channel especially plugged straight in. Pretty sure mine have EL34s, the shorter ones so they fit laterally in the cage.
Hello John. I two of them when they first came out. Gigged them for three years. They are a good amp for the money. Never seen one with EL34s before. If they fit, and as long as they are biased correctly they should be fine. Thanks for watching and take care.
@@vintageguitaramp_guitarteacher… and, of course, you’re absolutely correct: the amp has 6L6s all the way!
Great lil amps. I picked one up 5 or 6 years ago almost unplayed. The guy is an acoustic guitar player and in the 90s decided to try electric. Bought a JTM 30 and a Strat brand new. Played them a few times for a total of a couple hours he said. Then just stayed with acoustic. Ha, it still had the hang tag on it from the store. It was wrapped around the handle. Mine is a 1 12" version. Man I love those Heritage speakers.
Had a JTM 60 earlier, 1 12" again.. Something about the gain on the 60 just didn't sit right to my ears. I swapped out the el34s for kt77s and it was better but even with vintage mullard pre Amp tubes I just couldn't grab that over my Soldano or Reinhardt 18. Sold the 60. Kinda regretted it. Then picked up the 30 and that was it. After switching pre Amp tubes , setled on 12ax7b. It's my number one now. Even sold my 77 JMP 4 hole 50 watt and kept the JTM 30. I thought the 6l6s might have been the difference from the 60 sounding just good but I don't really know. My drummer is loud so I play this a little over 3/4 volume so I'm getting some power tube saturation for sure.
It's so good to hear you state the 30s don't heat up like the 60s do. My 60 was fine but I always figured it would overheat sometime. Cool video.