FYI if you follow everything shown in this video the amp will not work, the cable mods and work that must happen on the controls board is not included in this video. I had to study the later live stream about the Origin 50 but is confusing because all is not spelled out and its made more complicated by the addition of the diode mods in the amp shown in the video. No novice will be able to complete this Origin 50 mod package! All that said, the ideas presented here are very cool and well thought out and when I did complete my Origin 50 the results were fantastic!!! Thank you for sharing your time Jason to make all these free videos, just think you should warn people about the missing puzzle pieces. cheers
Yeah this seems difficult and I've done a fair amount of mods. There's no BOM, schematic or instructions etc. Seems like there are gaps in the information needed to complete the project correctly. Where do I find the missing pieces?
Just performed this mod on my Origin 50. I can say without a doubt that if you own one of these amps, this mod is a MUST. Now, while it's a little scary doing an amp mod if you've never done it before (this is the first time I've taken a soldering iron to an amp EVER), if you follow the advice about safety and soldering procedures, you can do this.
Lol thanks. Does it still sound good when you turn the volume down (or PPIMV)? love that you are a first timer and did it! I am too and trying to figure out the process for a 50w. Do I just use this video or do I also go through the 20w stuff? Am I printing certain things out? Like how would you do it again if you had too? I want to be prepared :)
Was considering doing the mod on the 50 but was not totally convinced yet because your super-detailed instructions were only for the 20... kind of gave up on it for the moment... thankyou very much for reigniting the desire haha. Gotta go find a used 50 now to do this! Cheers Jason.
Origin 50 with your mode truly smokes! :-) Great job! I know you refer to previous mods a lot in the video, but are you going to be releasing a documentation PDF with a list of modifications/components that you used in this specific example? It would be handy to have them all in one place. Keep up the great job!!!
Yes, I would like to see Jason's final modding results on the Origin 50 documented, and compare his expertise to my amp-hack abilities. I successfully modded a friend's O-50 by implementing Jason's O-20 modding tutorials as a guide. Did the 3-way José clippers and added Jason's fx loop board too. Definitely felt the need to drop the preamp voltages after the phase inverter. The new fx loop module needs to be located about a 1/2" further back towards the rear of the chassis to clear the O-50's taller filter caps. The loop board is grounded at a different grounding point too, compared to the 0-20. Also, I replaced the two original 2.2uF cathode bypass caps for V1 with 1uF's instead of Jason's recommended .47uF's for the O-20. The modded 0-50 is truly vicious sounding!
The Origin 50 can benefit from a shield between the transformers to help with inductive hum. A piece of aluminum works good, not 100%, but better. They really should have been farther apart. Thanks for the video!
Try gauss/belly banding both the power and output transformers with copper shielding tape (some disassembly involved to get the bellhousings off). Two or three wraps around works. It’ll reduce both the leakage from the power transformer, and the amount of hum the output transformer picks up from it. It’ll also increase the power output from both whilst reducing the amount of heat they create, bonus! Aluminium won’t stop magnetic coupling, you’d need a thick piece of steel for that or some Mumetal stuck on your aluminium shield.
Paused the part showing the top of the chassis, the power transformers too far back, it needs to be moved forwards so that the centre of the bell housing lines up with the centre of the iron plates on the output tranny to get the least magnetic coupling. I have an amp in a narrow JTM 45 chassis with the transformers the an inch apart like the original 50, however because they’re lined up properly there’s no hum. Can’t believe Marshall dropped the ball so badly on something so simple.
@@Jonathan_Doe_ Thanks for the tip. I'll have to try it on my remaining Origin 50 chassis. I sold the boards but will be using it for a new build. I just tried a piece of aluminum that I had on the bench and it did work, maybe 50% reduction for what it's worth.
The hum is audible when you're not playing. It would be hard to hear it when your playing quietly. Some people may never here it at all, I hear it. @@vin9976
I know this mod is more of a hot rod 800 setup, but it'd be interesting if you modded one to be more Plexi like and then had a shoot out between them and the Marshall studio amps as well. These amps are such a great value for mod projects if you put the work into them
The Origin 50 with it's bigger iron and fixed bias sounds better to my ears. Is it way way louder? How many db louder than the 20 or the studio vintage would recon?? Guess? This 50 you modded here sounds better to my ears than the Origin 20 you modded. I would like to compare this video with a 50 if you end up modding one to plexi specs. Thanks.
Ok, after watching this video, I'm still a bit fuzzy about what is done to the Origin 50 that is different or above and beyond the Origin 20 mod. Is there any way you can publish instructions to the Headfirst web site that outlines the 50 specifically? Thanks!!!
What of this pertains to the Plexi mod as well? I’ve seen the two 20w Plexi mods but they are a bit less detailed. Wondering what the main takeaways from this are and if they apply to the Plexi mod too.
Hey Jason thanks so much for your mod videos. They have been awesome. I'm thinking of doing a mod on a Origin. Do you prefer the 20w or the 50w? Thanks man!
Nice!! Have one of these amps in a combo would've love this when I still playing guitar before my injuries........seriously still really appreciate it though
Bought one of these today, but no one in my area really does mods, and last time I tried modding anything (dumble mod on a sd-1 overdrive pedal) I F***ed up heinously xD Such an awesome sounding mod though. It's perfect for what I want too! The guys from Mastodon used a JCM 800 2203 for their first couple albums and I'm chasing that tone on a budget. Might just have to drive a few hours to have someone do it haha. **Edit: Is there anything I can do that won't be of detriment without performing the rest of mod, but will add to/change the tone in any way while still remaining functioning? If that made any sense. Awesome videos though! New to your channel, lots of good stuff!
In your Live Stream of the 50w head...you show a board that has a couple extra things done to it. R63 and C29 are removed...and you've lifted a leg on R70. Do we need to do any of that with this original headfirst JCM mod?
How about a video on making the Origin 50 into what Marshall said it was? Stock it doesn't sound like it has any real origins or even a personality of it's own. How about a non-hot-rodded jtm45 with a 1987 cathode switch? Great videos, man.
I love the video! But please do a plexi mod on this one! Or can I use the info from the 20 watt version and get the same result? Thank you so much for posting these vids! You’re helping us diy broke musicians get the tone we love
Are you pulling more parts out than putting back in? I wonder why Marshall didn't just stick to their tried and true circuits like the plexi lead or bass circuit and the JCM 800 2203/2204 circuit but of course with these transformer sets and biasing schemes? Is this so everyone doesn't just but these instead of the more expensive amps? All I can think of.
On the 20, you tie the bottom of R67 to the top of R65, do you NOT do that for the 50. Also, you said you ended up putting a 220k in the R65 spot? Is that correct?
Why would Marshall prioritize one 12ax7 preamp tube to do the effects loop only leaving 2 gain stages for the entire preamp? It's like a 1974x circuit with an effects loop. I don't have much experience with Marshall, I don't know if the 1974x is considered gainy enough? It's not the 3 stages of the 1959 superlead circuit. i don't know any tube amps that do anything more than stick two jacks for an effects loop conveniently into the circuit where it will work. Actually my Kustom coupe 72 does that in fact, yet they power the reverb with IC's - which still makes no sense to me why you would prioritize a vacuum tube for an effects loop over using it for tube driven reverb or a couple extra gain stages. I would think the Origin 20 and 50 amplifiers are ultra clean unless they're using IC's for extra gain?
I'm gonna try the Plexi mod on my 50, which is currently stock. Can I follow this guide to remove all the stuff, do the re-routing of V2 and then just add the components for the plexi mod? Or would there be more to it? No Jose, straight plexi for now.
Hey how did the Plexi mod go? I’d love to turn one of these into a Plexi clone…complete with the Cleans but also the big growl that can be boosted. Any luck?
@@HeadfirstAmps The base mod in which I believe you reroute the fx-loop tube to act as an extra gain stage. He's going to add his own solid state fx loop as well if it fits. I am glad to have found an experienced amp tech in my area. The guy has done a lot of stuff for the golden earing back in the day and some other dutch bands.
Hi, the schematics for the Origin have not been published by Marshall, however if you refer to my O20 mod videos you’ll get an idea of what I’m doing to mod these.
does anyone have the exact list of components used on the mod? I only see photos but now an actual list. Plus in the video Jason went inbetween a few parts but never stated what he ended up on. Does anyone know?
There are parts listed in the Google drive share (linked to from headfirst website). Also check the last part of the Origin 50 livestream, I show all the parts there from Mouser.
@@HeadfirstAmps Thank You! I imagine the mod is almost the same as on the 20? We watched your mod on the 20 and it really came to life with output tube distortion, best kind!
I know this is nothing to do with the origin but I heard Dave Friedman did a mod on the Marshall sv20h to help it not be so harsh do you know anything about this mod to help it
I understand he makes it less bright. I don’t know exactly but my guess is that he reduces the bright cap down to 100pF and also puts the ‘fat cap’ mod in on the v2a cathode.
It's a great pity that amps are not coming out WITHOUT the need for mods, I'm glad that I have good money in my hands and still counting rather than wasting, .......... That distortion sounds awful, sorry. 🙂👍🇬🇧
