1967 Marshall JMP/JTM45 - RESTORATION PART II

[@LeonTodd]

Loved the clean Hendrixy/funk stuff. Must be the Dave Dobbin paying off :p Lost it when you played Waiting For the Bus too!

[@HeadfirstAmps]

It just felt like the right thing to play!

[@Sealevelsounds1]

Simply roars with the Les Paul plugged in! Great work Jason!

[@hydorah]

Yeah nice job mate. You found and that ringing, singing kind of sweetness. Grail tone

[@augustschmid3893]

Listening to that amp before and after your restoration, it's clear you brought back that Marshall sizzle and kerrang! I'm just a hobbyist, but I may need to buy a LCR meter...seems like a good investment to test in circuit. Cheers Jason!

[@mookytc]

As always Jason very informative from a technical aspect and great riffing as well!

[@curtisprice9806]

DREAM COME TRUE " THOROUGH" WALK THROUGH OF A 1967 MARSHALL!! INFO GALORE 👍👍👍🧨😀 THANK YOU!!

[@RealRockGuitar]

What a sweet old amp! Great job as always Jason.👌

[@94xjrgodown2]

Nice couple of licks to DC’s Overdose!

[@ironageamplification1791]

Amazing! You really saved this one, Jason

[@j1m1jam]

You mention why change out old caps when they read in spec (Capacitance). Why not check the equivalent series resistance (ESR)? This too is very important and if the caps have high ESR, this could cause problems and need to be changed..

[@jcwear89]

Sounds more vintage now, and like a different thing all together - but really cool! Still maintain it sounded excellent before though. Love the couple of Zz top numbers you squeezed in at the end there 😊

[@lucastmello2756]

Great work! Congrats Jason!

[@vl292]

C’mon now all the gurus, please bitch about not replacing electrolytics. I though these guys would have a field day in the comment section. Absolutely lovely work and nice that you’re sharing all this. Thank you!

[@Toobzilla]

awesome piece of loud history!.. love the technicals. i built a 5f6a circuit into an old traynor 1x12 combo that i gutted completely & revamped. im currently in tweak mode with it which brings me to ask. im noticing a lot of the *hotter* channels be it stock or triodes @v1 run in series vs.parallel run the hotter channel into v1b. assuming its intentional is it to avoid the POW in volume im now getting as i hot channeled into v1a first? seemed logical to my inexperienced self. im starting to question that decision, lol. Great content! (& playing as well).. keep up the good job mate.

[@lukerobertson10]

Nice Jason .. overdose is a great riff/song ⚡️

[@markkinney5030]

Amp sounds good! I like the tone with that Les Paul sounds like old school AC DC stuff and everything else! Nice! Its not my amp but i sure wish i had it. Cool Man

[@nfchilton]

Great work, great sound. What cab/mic etc did you use here? Or through of those modern IR sim things?

[@johnmarshall3903]

Great amp Jason. Wish you would have shown the transformers. Were they 1202-133 power and 784-128 output? Strange that it was a jmp and not an early black flag.

[@HeadfirstAmps]

Transformer specs are given in the video description

[@hannowirth7245]

The plate voltage is way too low, should be about 440v with the GZ34. What about the heater voltage?

[@HeadfirstAmps]

heater voltage was fine

[@benburnett8109]

I see you did the BJB mod. Congrats. This mod is the mod that puts all other mods to rest. The BJB mod will go down in history as the singular mod that changed the face of modern rock. Jose who? Friedman who? Sir34 who? That's right. Those mods are long forgotten. The BJB mod is the only mod that is these 3 things: 1) the past 2) the present 3) the future. All the others will since be forgotten. Variac who? Sir36 what? That's right. The ONLY MOD IS THE BJB MOD. 1 mod to rule all other mods. Love and peace, Ben

[@HeadfirstAmps]

Love your work Ben

[@JohnWiku]

What is this BJB mod thingamajig?

[@ronjinks8932]

Isn't this a "Black Flag" JMP 50?

[@johnmarshall3903]

That's what I thought too, but it has a JMP front panel. Very strange

[@kxmrock]

I was told to change the filter caps every 10yrs because if they fail it could be catastrophic

[@kxmrock]

Sounds Great

[@JohnWiku]

That's just money grab, it's unnecessary to do that EVERY 10 years. Every 20-25 years? Well, I'd see a reason for that...

[@hannibalbarkas1350]

People like Steven Fryette and Dave Friedman who actually know what they are doing say that's a waste of money. Change them when there's an issue or maybe in really old amps, especially when it got stored a long time (using them actually keeps them healthy).

[@PsionicAudio]

I tell people they were designed to last 10-15 years, so to be mindful of that. After 20 years a closer eye should be kept. But sometimes like on this JTM everything still measures and functions OK. So no need to change, but the tech needs to confirm those measurements.

[@qua7771]

I wouldn't hesitate to change them. Vintage parts are nice, but filter caps are expendable. They have a fairly short lifetime, and new production electrolytic caps are much better. Some people figure out ways to hollow the vintage caps, and fill them with new ones which is neat.