Lets Repair this famous "Beano Blues Breaker" Marshall JTM-45
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- Опубликовано: 12 июл 2024
- So, you’ve put in a new matched set of power tubes. Every tube lights up as it should. But the sound is terrible, and the volume is way too low. That’s what the problem is with this classic Marshall JTM-45 Blues Breaker amp. Let’s get his baby sounding “Clapton Good” again. Could I get that elusive Beano sound?
You may also get a better understanding of terms like “Transconductance” and Gm.
Video Index
00:00 Introduction
00:32 What are your most influential albums?
08:45 Testing the power tubes
11:10 What is Transconductance and Gm?
16:20 Testing the Filter Capacitors
21:30 How to replace the filter cap that’s under a Marshall circuit board
29:50 Replacing the Bias Capacitors
35:50 The Fuse with a “ticking noise.”
38:20 A quick test for PreAmp tubes
39:10 Setting bias using an oscilloscope and Bias Probes
42:20 Why is one power tube not working? Two ways to check.
51:37 The difference between Cathode Current and Plate current.
56:27 The Sound Test. Did I get close to the Beano Sound?
Rod McQueen's "Sliders Pickups" sliderspickups.com
If you got something out of this video, even if it's just indigestion, can you please find and press the LIKE button, and consider SUBSCRIBING. 
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My original inspiration (at age 18): Robin Trower's Bridge of Sighs.
My current inspiration (at age 65): Robin Trower's Bridge of Sighs.
HAHAHAH! There's nothing worng with that list of inspirations. We used to play"Too Rolling Stoned". I should see if the guys remember enough of it to give it another hit.
@@theguitaramptech Technically that song and much of Trowers work is simple. But getting that 'feel'... well 40 years on and I'm still trying.
I still attempt "Daydream" ("Twice removed...." album) every day and I still fail.
But hell it's fun trying.
My favorite after-school albums were Santana's "Borboletta", Robin Trower's "Bridge of Sighs"....and Yes "Close to the Edge".
Those were always on the turn table for sure the rotation of my excellence in music.
Yep. Three of my favourites. Each with brilliant playing.
Diary of a Madman and Tribute.
Ozzy!
Out standing video. I would give the left one for it. Such a warm sound
Please don't, Monty! I have two of my own that are going unused!!
I'm so happy that you like the video!
For me, it was the Back in Black album.. I'm a younger guy, 31 as of now and came up in a pretty sheltered home and one of my friends loaned me the Back in Black CD and i will never ever forget, for some reason my janky CD player skipped the first two tracks and i was met with what i now remember fondly as "what do you do for money honey". I had never heard anyone play guitar that way and i decided right then, I'm gonna be a guitar player.
Such fond memories
That is a great story, Gary. Thank you for sharing that with us. Angus makes us proud!
@@theguitaramptechanytime! Just stumbled across your channel and a lot of this really resonates with me as I just got into building pedals and something about the whole process has really reignited a lot of the feelings I experienced when I first picked up the guitar. A lot of it is very frustrating to learn, as there about a bazillion possible points of failure in even the easiest circuit layouts but when I flip the toggle or hit the switch and that drive pedals hits the front end of my amp, none of that matters and I feel like I could do anything. Thanks so much and keep up the good work!
Your age belies your insightfulness!
Seeing that "real waveform" brought home to me the Class AB video you did a couple of weeks ago. It was amazing to see what you had talked about in real-life.
What a perfect coincidence it was, Les. Of course, in this case you didn't need an oscilloscope to find the failed screen grid resistor. Just measuring the voltages on pin 4 would have found it quicker, but I saw it as a perfect learning exercise to help understand the Class AB overlap. I am very satisfied that you picked it up, referred back to the Class AB video, and gained a better understanding. After all, not everyone has an oscilloscope at home. Thank you for taking the time to write your comment.
Machine Head, Disraeli Gears and Paranoid all got my blood pumping but the standout for me was CCR, Bayou Country.
That's a very interesting selection. The first 3 are in a similar category, but CCR is different. I think John F is a very underrated guitar player.
@@theguitaramptech Agree completely, he is and that down ang dirty rhythm just moves my soul.
Chris, you have one of the best amp channels, bar none. For years, I've been watching Uncle doug and d Lab, etc. Long before i knew what the hell they were talking about. It's always great to see what a pro does with a vintage amp. Btw I want so badly to wire up a turret board for that bluesbreaker, hahah.
Locally, there is an early 90s vibroverb reissue for a decent price , I'm thinking about grabbing it and hand wiring it. So much fun.
Hello Chris, this is once again one of your terrific videos. I am already looking forward to the next one. Best regards from Germany 🎸🎶
Guten tag, Markus!!
Although a big Queen fan in the early 70's, the one album that got me started on electric guitar was Hotel California. The whole gatefold album with poster and liner notes was a treasured piece of art. I bought it in 1977 and still have it. That solo from the song has echoed through my whole life. I finally learnt to play it note for note 40 years after hearing it on my record player
What a huge sound Brian May got from his amps. One of my greatest honours was to work on Brian's Aussie AC30. It sounded like no other AC30 I have heard. I was so tempted to reverse engineer it, but I respected the work of his Tech too much to do that..
The Hotel California solo has got to be one of the best "composed" solos in musical history. So melodic. Well done for learning it. I wouldn't have the patience.
@@theguitaramptech Thats brilliant! What an honour! Brian May is such a tasteful player, too intricate and complicated for me back then...lol. I just loved the whole sound of the band. Having said that I do remember the sound of Apache when the twenty golden greats album was out in 1977, that sound of deep lush reverb was also a memory of influence. Keep those tech videos coming! Brilliant channel!
@@fostexfan160 Thank you so much!
Excellent video. Happy for the wrap up of mhos etc. ... Favorites: The 3 first Hendrix and Cream albums, and funny enough a lot of Motown stuff. I discovered the Beano album later.
Thank you QD. What a great selection of Favourite albums. It doesn't matter when you discover Beano...so long as you did.
Be like no one else but yourself Chris but everybody's got their influence.
What a great video: an hour of entertaining and informative stuff. Mind you, I'm a valve amp nerd.
You need a decent reactive attenuator (I use Ironman II): get the "tone" without triggering a seismic event.
I am still a little sceptical about load devices. I use a Weber reactive load for my repair work, but I don't know if I would trust a vintage output transformer's survival for a whole gig. Call me "old school". I'm so thankful that I lived through an era when I could play a Twin on "7" or a JMP50 on "8"....other than the hearing loss!
@@theguitaramptech I've got serious mid and upper frequency hearing loss, AND tinnitus. I had fun in my early years but if only I'd got an attenuator sooner!
I have a Weber but although it reduces volume it doesn't present a constant accurate impedance load: the Ironman does. The downside is that they cost around £1,000... ok worth it for what's left of my hearing, and they don't kill the tone like cheaper ones (eg Weber).
And... I've just watched your vid on why you recently shaved your head. Power to you and your daughter. I'm not religious so not much I can do but wish her the best of outcomes.
@@digitalchris6681 Thank you Chris. I will look into the Ironman. I mainly use my 18W Marshall 1974 for live work. I'd love to use my Brownface Concert, but its way too loud at 40w. Maybe the Ironside on that may work. Time for some research.
@@theguitaramptech Chris, I've been using the Fryette power station for 8 years now and can't be without it, to be able to enjoy my amps. Running an amp on 10 or around there, will cause any weak tube sockets or weak tubes to die though. I just make sure my fuses are right and so far so good.
Very Cool, Thankyou. Awesome amp, nice work. My first Album, the one that I Listened to Over and Over again was ....... The Album of the Soundtrack of the Trailer of the Film of Monty Python and the Holy Grail, LOL. Not really Guitar Music but still. In mid 1980's when started learning Guitar, I 'Discovered' Goldrush Live album and thought Phil Emmanuel (Tommy played drums in this band lol). Phil's AMAZING Guitar work inspired me so much. But before that Lynyrd Skynyrd and John Denver were my Guitar Inspirations. Cheers
Phil was great. I got to see him and Tommy together a couple of times. Mind blown. I had forgotten about Goldrush. Thanks for the reminder.
This is why I enjoy the responses in the Comments. I would not have thought of John Denver. Can you think of your favourite JD guitar song for me to play?
Two weeks after the Beano album came out every guitarist in Detroit Michigan USA was trying to get that tone..Any guitar with humbuckings disappeared from the pawn shops overnight.Fender Bassman turned up all the way came really close.I still use that setup
What a cool story. What a time to have been in Detroit. Thank you for sharing that with us.
That would figure -- the JTM45 was a clone of the 1959 Bassman. With a few parts substitutions because American parts were crazy expensive in England.
Enjoyed every second of that. The anaesthesiologist must have had a "Hangover"?
Thanks mate!
my high school years were much more synth-focused, but I suppose the early Smiths and R.E.M records were my guitar renaissance. Oh, and The Church and Go-betweens and Saints
and/or Fripp and Belew with Bowie; early Simple Minds; Robin Guthrie in the Cocteau Twins; John McGeogh in Magazine and Siouxsie and the Banshees; the Cure ...
What a mixed bag, Tim. I thought Johnny Marr was so uber cool, but Robert Fripp was "da man" in your list for me.
Very good! All the best from Austria!
Hallo Philip. Good to hear from you. Thanks for dropping by to say Hi.
Beautiful math! Thank you!
You're very welcome, Bruce!
Can't wait to watch, been loving your videos! Learning a lot for my own vintage amp projects🙂
Me too. I've got a coffee in one hand and toast in the other and settling in for the video. With Chris' videos I always wonder "What am I going to learn about today?"
I am so happy that you liked this video. It was a mammoth editing exercise but a joy to repair the amp. Comments like yours make it worthwhile.
@@theguitaramptech well if anyone understands that its me! Haha I just wrapped up a 12 part series on my channel rebuilding a 65 Vibrolux Reverb as my first major project. It took so much to do, so I appreciate when others also go for it! 🫡
I can see that, brother. I am watching that video series now. Your amp sounds brilliant and that ES345 looks stunning. I appreciate the trouble you have gone to to record your audio. Good production won't make a crap guitar & amp sound great, but it will avoid clipping (which I still have issues with) and overcome some room acoustics. My room is basically a cube...the worst possible shape, but it works for my repairs so I do some "sound repairs" during editing.
@@theguitaramptech Thank you! It was really difficult doing that, but I felt like the amp was worth the work (also after putting in as much time as I did on the restoration, I wanted to finish strong by showing how the amp really sounds to the best of my ability). It was brutally loud, I had earplugs in the whole time haha. I actually just talked to Lyle at Psionic audio about my recording techniques, his situation I think is similar to yours with a bad room which makes it hard. My setup for that was an SM57 up close, and then my phone recording off to the side of the amp about 5ft in stereo to capture the room and blend that in. That worked best for me.
For me deep purple and wings over America, fantastic bass
I often think that Paul is very underrated as a bass player. He overshadows his musicianship with his songwriting and personality.
You make good videos. I like how you show us how you diagnose problems. And I like how you show us the sine wave on the scope. And you play good.
Thank you Zack. I appreciate your comments very much. Yes, it takes more time to demonstrate the issues and the amp performance with schematics and oscilloscope, but if it helps you to understand, then it is worth the effort.
Hey Chris, Mr. Clapton was always one of my favourites..😎 Great video and fab amp..So much detail and info, love the way you seek out and remedy the faults..Learning lots mate, although at times; it does get away from me..!.. Nice demo, and lovely guitar..Stay well..Ed..UK..😀
Great to hear from you again, Ed. If you tell me that you are Eric's neighbour or grew up in Ripley, I will be on the next plane to London.
I hope my videos don't go so far as to lose you.
@@theguitaramptech Hey Chris, no not Ripley but I am about an hour from his old home..😃 Your videos are very inspiring and funny as hell sometimes..! I am picking up loads of stuff and no, you won't lose me as you make your videos so interesting..Many thanks once again for sharing your expert knowledge..😀
Cool,video, had to sub , cheers from New Zealand
Cool! Its nice to have another Kiwi in the family.
For me my two faves were the Beano album and B.B. King Live at the Regal
100% agree on both of those Rick. Still 2 of my favourites.
2X12 Bluesbreaker extension cabinet is needed preferably with bluebells. Only then you can get close to Eric's tone back then.
I agree that would sound awesome, but I don't recall a photo of Eric using a 2x12 cab. If you come across it again, could you pls send me a link?
My two most inspiring guitar tones were both conjured from the same artist, jimi hendrix, one is the monterey pop festival version of "like a rolling stone" and the other is a studio out take from the loose ends album recorded in london where jimi was in the studio trying to instruct the drummer what beat he needed to Launch into a cover of blue suede shoes after the "grass" was passed to him, the tone of this short out take is so clean with just a small hint of distortion and a giant wallop of sustain so that on the short lead the notes just linger with the clean fatness, sorry if i sent anyone to my quest and i apologize to their wives if i have.Edit, pretty sure that trac was recorded with a modded jtm 45 hence my post here.
Noel, I would love to hear that Hendrix outtake. Where can I hear it? I no longer have a wife to pass judgment or comment as to why I must listen to such noise at a deafening volume. Little wonder we divorced. One of my mates has these outtakes of a Beatle recording session. The sound that George had when he was noodling between takes was amazing. I wish I had a copy.
I also have three copies of the Beano album - vinyl, CD, and direct-from-master-tape-to-CD. It seems that there are two major Clapton tones on that album - a bright, rather stinging tone which he seemed to prefer for the rest of his life, and a fatter, creamier tone which drove us all crazy and still does. The story goes that one of the solutions to Eric playing Too Loud For The Studio was to face his amp to the wall and cover it with a sound blanket. It was still crazy loud and leaked into everything, but that blanketed sound - which he did not even like - became our Holy Grail. Other tracks were either overdubs or did not much matter, and those have the amp unblanketed and very bright sounding. Live recordings of the Bluesbreakers from that era show Clapton playing with a very bright tone, presumably because that's the way he preferred to sound.
So if we want to sound like the Beano album, get a JTM45 1962 combo, a Les Paul, and throw a blanket over the amp!!
VERY interesting. I can get CLOSE on the bridge pickup with the Tone knob rolled to about 3-4 with my pot taper. But you're right it became our Holy Grail of tone. He never came close to a unique tone once he moved to Strats. I love Strats, but they are a cliché of themselves.
Long ago I have seen a video were he explained the Woman tone. Not completely sure but I think he used both PU´s on full, and the tone knobs wound down.
@@qddk9545 There was never any mystery about the Woman Tone. Any of us guitar players back then had come across it by fooling around but didn't think it was useful, not aggressive enough. It's neck pickup, tone all the way down, and either amp overdrive or a fuzz like a Tonebender..
@@elbowjames7625 I am from back then (1952) 🙂
@@qddk9545 Me too. I guess I was in a unique environment. It seemed like everybody played guitar around me. There were jams all the time and if somebody did something new, we all jumped on it. Everything got examined discussed and attempted. I didn't know this was unique until I moved to Los Angeles.
Allman Brothers Band Fillmore East. Technics turntable, big Marantz and JBLs. Wore out 3 copies.
Yes! Yes! Yes!. What a mighty album. I love their version of Stormy, but for me, it's all about "The Whipping Post".
@@theguitaramptech Amen to that, brother! And "In Memory Of Elizabeth Reed" was clearly influenced by John Coltrane's rendition of "My Favorite Things"
Duane Allman was grossly under rated. Clapton would tell you that in a heartbeat.
Duane's lead break on the outro to Wilson Picketts cover of "Hey Jude" proves it. I cam sing the praises of Duane till my jaw falls off!
Cheers, and happy teching!
@@jpalberthoward9 Thanks mate!
This is quite interesting, thanks. I have one of these for the US market the plate voltage is a lot lower, more like 380. It doesnt sound right at that voltage to me with KT66s. I boosted mine to around 420 and at the same power dissipation it came alive. Also, the US power transformer isnt mounted at 90 degrees to the OT so it is noisier.
It’s gonna be mayall and the blues breakers for me Chris!
Good call, Joe!
@@theguitaramptech Swear to god m8. The only amp that would beat your SLO-100 video would be the jtm45. Thanks very much!
@@jjs3863 Thanks Joe. Your comment made me laugh. It reminded me of a joke: "Wife buys hubby 2 ties, one red, one blue. To make his wife happy, he wore the red tie to work the following morning. She angrily looked at him and said, "So, what's wrong with the blue tie?"
@@theguitaramptech I know, right? But I confess. I am a claptonian. My Strat is a 96 blackie. And my second ‘jam to’ album is the crossroads box set.
@@jjs3863 HAHA! Got it!
Hi, Chris. Great video. Nevertheless I would like to comment that unfortunately your criticism of the value of the cathode capacitor at V1 derives from an example of "lost knowledge" about tube amp design. The use of a capacitor with unusual high capacitance in this place is not an error of the designer but an attempt to improve the shielding effect of the cathode against hum influence by the ac operated filament, especially in input stages. A 330µF capacitor reduces the cathode to ground impedance from 145 to 10 ohms compared to the standard 22µF capacitor (at 50Hz mains frequency). This method is described in historical tube books. Greetings from Germany, Wolfgang (please excuse my english).
Thank you for your knowledge, Wolfgang. I am sure you are correct, but like many amp designers, I use the cathode bypass capacitor value as a way of tailoring the sound at this all-important first triode stage. For me, it is an acceptable trade-off. I am sure you know this site, but I often refer to it www.ampbooks.com/mobile/amplifier-calculators/cathode-capacitor/calculator/
Which part of Germany are you from? I love your country. I was lucky enough to do some work at an instrument company near Hanau several times.
@@theguitaramptech Hello, Chris. I must admid, but I did not know this capacitor calculator until now. It shows correctly that compared to a high pass filter the low end frequencies may only be reduced up to 6dB. Regrettably not all youtubers do understand this fine difference.
Indeed I live just 20 kilometers south of Hanau. What a coincidence!
Keep up the good work. Kind regards to Down Under.
Wolfgang
@@WolfgangGrimm-xm4nw That's amazing, Wolgang. The company (not named) was actually in a smaller town called Maintal. I worked with a young talented engineer with the family name Grimm. I bet you are related.
I just remembered. His name was Max Grimm. 😊 I liked working with him.
@@theguitaramptech Yes, Max is my nephew. No. Sorry, just kidding. It's true the famous story tellers Brothers Grimm lived in Hanau, but the name 'Grimm' is distributed all over Germany and unfortunately I don't know a person called Max Grimm.
A Beano JTM 45 would be point-to-point, cobber. No PCBs back then, I’d offer,
Oops. Did I say this was an original JTM45? Its a reissue, of course. (Sadly by the time I have finished editing any of my videos, I am so sick of my voice that I couldn't stand to watch it again, so I will happily trust you that I said it was an original early 60's model, which it is not). However, I don't know about point-to-point. I expect it would have been wired on a turret board, but I'm happy to be corrected on that.
I couldn't bear saying the wrong thing so I forced myself to go back and have a look again. Fortunately, I only had to endure me until 03:17 where I clearly said it was a "reissue". So what was your point cobber?
@@theguitaramptech Hey Chris: quite possibly you didn't actually say that, but I was led to your article straight from old mate Stuart's (ukguitarampguy) article [ruclips.net/video/sPdSEMbLW04/видео.html] on fixing an older one, kinda struck me. And yes, of course, you're correct: a turret board it is, indeed!
@@theguitaramptech 🙂See above: I guess even a PCB-based one is still a "classic" .. all good. I really liked your presentation, btw.
@@johnvcougar Thanks John
This guy should have its own section inside GPT AI… because when he’s gone, no one is going to know what he knows, the way he knows 😢
You funny guy! I don't even know what GPT AI is.
It's not bad practice to have back ups for the back-up,and although I'm a little shy of your experience (age) i immersed myself in a mixed bag but mostly SRV,Tommy Emmanuel and a good dose of Billy Duffy and Brian Setzer
That’s a fine bag of guitar slingers, Bruce. I got to see Electric Tommy when he was in John Farnham’s band. What a Tele wielding master!
@@theguitaramptechwas an impressionable teenager mid 80s and there were many more, too young to attach myself to the earlier players but I've covered some ground as I got older, many thanks for your replies,sadly I worked all night so have had to revisit. Catch you on the next one
@@brucehayes7251 See you Bruce
I may be wrong but there was a treble booster in Eric's rig... That could well be some of that missing sauce
I heard those rumors, too. I wish Eric could confirm, but I can’t recall what pedals I was using 5 years ago let alone 50 years ago. I think it would work great. Keep the neck pickup bright and useable and roll off the bridge tone and we’re in Beano heaven!
@@theguitaramptech I've seen Eric talk about it. And from personal experience if you have a TB in front and roll that tone back you get something special. I can hear that TB all over the Beano. Eric says roll the tone off then edge it forward until you just hear it change..
@@Swine-O-Sonic YES! That's exactly how I do it, but I don't quite get there. I haven't seen that interview, but I am taking your word for it and finding or making a TB! Thanks for that
AC/DC Dirty Deeds!
What a mighty band and what a sound Angus had. He was also about 20. Its about the time (1976?) when we were on the same bill as ACDC. Really nice and approachable fellas. They were still on the bottom rungs of the ladder that would take them to international stardom. Good choice, Dennis.
I listened to the greatest ever Frank Zappa, "Hot Rats"
Cool. Zappa was a great composer, but I never got into him. Time to give Hot Rats another spin.
It was Bat out of Hell. No idea who played the instruments 😂
That went over my head. Please translate for the simple-minded.
Im a little older Chris. Mine was Meet the Beatles
Woo hoo! Great album. Thanks Monty
Rush - 2112
A cool band and album. Its a shame they never made it big in Aus. Alex Lifeson is such a good player.
Van Halen 1
You are clearly younger than me...most people are. It was a ground-breaking album, for sure. EVH was such an innovator.
Cream Wheels Of Fire
Great call, Kim. For me it was White Room off that album. I loved young Eric. He was only 23 when Cream folded. Unbelievable talent.
Free. Fire and Water
What a great album with probably their most well known song. My band still plays "Alright Now" and "Wishing Well" (from Heartbreaker). I loved Koss's vibrato.
Deep purple made in Japan. Blackmores playing on that made me stick to guitar.
What a great album that still is.
Status Quo. In my defense I was 6.
Hey I liked Quo. We used to do a couple of their songs until it started to develop tendon issues in my pinkie!!!
Those wire leads are getting so short, that in the future they'll probably be using Bluetooth to make the connections.
I don't know whether to laugh or cry! Your comment has probably more truth than either one of us would like to consider.
@@theguitaramptech Yes, Please select your tubes:
A. The Mullards in the back room.
B. The Sovtek's sitting on the shelf in some Slovakian warehouse.
@@wesleyc.4937 Yep!!
LZIII
Jethro Tull
Wishbone Ash
Allman Brothers
Cream
Santana
Those bands between
1968- 1974.
Lit my music guitar fuse.
Like my Jedi surfing hero
Michael Petetson.
That and my moded.
Illegal ( back then because of Mesa Boogie law suits)......
two channel clean and distortion
Black face Fender Bassman.
From my friend Charles Rook
In Santa Barbara. Ca @ Fancy Music
and great compatriot of ..
.Paul ... Rivera
A famous LA Amp tech.and master amplifier builder.
PS: plus LATER
Midnite Oil
and
Spy V. Spy
A
@@lorenzomcnally6629 Hmm... I confused Lorenzo. Are you in LA or an Aussie? What a great list of bands. I forgot about Wishbone Ash.
@@theguitaramptech
I am American. But, Lived in Melbourne, Vic for a while in 1989-90. Studying at Geelong, and RMIT and Melbourne Uni.
California is home. But Australian surfers and tennis players are my heros.
And yeah that Wishbone Ash twin lead sound is fantastic. Especially that opening track on their first album.
"Lady Whiskey" the live sound of that amps last note full ending is gorgeous.
Still have friends in Gippsland, Vic. Hope I can get back there one day. Cheers. Loved your vid. That Blues breaker JMP 45 Marshall rules the roost of those mid sixties amps in the tone department. Well done.
@@lorenzomcnally6629 Thank you for clearing that mystery for me.
I loved the look of Wishbone Ash and the Flying V's. ARgus was my favourite. I hope you get back to Aus one day.
I got to do both of the brilliant Martin Rotsey's AC30s. Two wonderful JMI examples. What a great sound he had.