Marshall Origin 50 Drop-in PCB mod

[MadAsAHatter]

I've had the Evolve-DIY (Jason Tong) drop-in PCB mod for Marshall Origin on my project list for a bit. I was waiting to come across an Origin 50 at a good price. About a month ago I was able to get one from GC for $300. Cosmetically the shell was a little rough, but everything else was solid. Cosmetic issues weren't a problem since I planned to recover the shell anyway. After getting the Origin I ordered everything else I needed. That took a while for it all to be delivered. By mid this month I had everything in house and was ready to start.

I started populating the board the other weekend. I didn't get overly far in that sitting but it's a start.

Was able to work on it a little more this past weekend. I've gotten a good chunk of the resistors on the main board. There's 1 or 2 components like that 5 watt resistor that's slightly off kilter and bugs my OCD, but it's soldered on there solidly. So far I'm happy with the neatness and how it's all progressing.

 

[HomespunEffects]

As a staunch Marshall guy, I’m no fan of the Origin series. Having a full PCB replacement is the only hope. Keep us in the loop, I’m interested in the results.

 

[MadAsAHatter]

As a staunch Marshall guy, I’m no fan of the Origin series. Having a full PCB replacement is the only hope. Keep us in the loop, I’m interested in the results.

Here's Jason's demo and overview video of the mod.

 

[SillyOctpuss]

That looks like a cool project. I've never heard of Evolve DIY before. I was having a look on the site and man their pcbs are expensive.

 

[Humbug]

Was able to work on it a little more this past weekend. I've gotten a good chunk of the resistors on the main board. There's 1 or 2 components like that 5 watt resistor that's slightly off kilter and bugs my OCD, but it's soldered on there solidly. So far I'm happy with the neatness and how it's all progressing.

View attachment 42746

You got them off the board, that's the main thing.

 

[MadAsAHatter]

That looks like a cool project. I've never heard of Evolve DIY before. I was having a look on the site and man their pcbs are expensive.

The $150 Origin board set was a bit pricey, but worth the cost. At $45 the rest of them are pretty average price for PCB's. They're top quality. The board is nice and thick. The trace are heavy duty (for lack of a better word) that won't burn out if you make a mistake or go back and forth with mods. Plus you get all the documentation (schematic, layout, BoM, etc.) you need to complete a build. I got the 2 Merlin (Wizard) boards while I was at it for projects later down the road.

 

[Mikael Dez]

I've always wanted to do this but I have zero experience soldering board circuits and feel like I'd mess it up.

 

[SillyOctpuss]

I've always wanted to do this but I have zero experience soldering board circuits and feel like I'd mess it up.

If you want to learn to solder start off with some basic pedal kits like low parts count boosts or get a bunch of scrap components and wire and just start connecting them.

It's pretty easy but it can take a while to make solid reliable connections. You'll definitely want some basic projects behind you before you tackle anything as big and complex as an amp.

 

[Mikael Dez]

If you want to learn to solder start off with some basic pedal kits like low parts count boosts or get a bunch of scrap components and wire and just start connecting them.

It's pretty easy but it can take a while to make solid reliable connections. You'll definitely want some basic projects behind you before you tackle anything as big and complex as an amp.

I’ve done a pickup swap and it was successful in that it works but damn is it messy lol - my shaky ass hands

 

[SillyOctpuss]

I’ve done a pickup swap and it was successful in that it works but damn is it messy lol - my shaky ass hands

A Big ass magnifier and blu tac were the top tips that helped me really nail soldering. A big blob of Blu tac is great for holding stuff steady while you solder. Oh and switching to using old school leaded solder and using flux really upped the quality of my joints.

 

[2dor]

I'd love to do something like this one day

 

[Humbug]

I'd love to do something like this one day

I couldn't find an appropriate "do it, do it"-style gif, so you'll just have to imagine it.

 

[gearJunkie]

and using flux really upped the quality of my joints.

^^^^ This ^^^^

 

[Humbug]

I've always wanted to do this but I have zero experience soldering board circuits and feel like I'd mess it up.

There are some fantastic soldering tutorials from The Olden Days when men were men and lead was healthy on YouTube. Like this series:

 

[MadAsAHatter]

More done on the board today. Resistors, most capacitors and tube sockets are done. Diodes, connectors and other misc. components are left on the main board. Except for the lone resistor I still have the secondary board with all the pots left as well.

 

[MadAsAHatter]

For anyone who's interested in doing something like this, I'd encourage you to look into it. So far it's sitting between building a pedal and building a full amp. There's no wires you have to solder or route through the chassis, it's all done by connectors. So all you're really doing is soldering components to the board, kinda like putting together a large pedal. Then it's just plugging things into the connectors.

I'd say if you could build a pedal you could do this project; just be mindful of voltages once things are hooked up and running while you do any checks.

 

[MadAsAHatter]

I'm done, but not done. Both boards are populated an mounted in the chassis. I'm just missing one connector wire that I didn't realize I needed. I was able to reuse all but one connector wire from the stock board. The one left over was a 5 pin one & I need an 8 pin. So unfortunately I'm not able to test it out yet. In the meantime I'll start working on recovering the shell.

 

[Mikael Dez]

I’ve decided that this is my next project when I’ve gathered the $ and convinced the wife

 

[MadAsAHatter]

I got my missing connector harness Thursday. I couldn't find one with connectors on both ends, just one end and open wires on the other. Since I don't have crimpers to do the open end, I bough 2 and spliced them together in the middle. That seems to work just fine.

So I got the harness situated and plugged in. I fired it up, did the initial checks, got it biased and gave it a short test run. I'm happy to say everything worked on the first go round.

I haven't spent a lot of time with it yet, just enough to make sure all was working properly and maybe an hour dicking around with the knobs. I didn't crank it yet or really try to dial it in so I can't comment too much on sound yet. I can say low gain mode seems to sit somewhere between JTM and JCM. High gain mode sits in the JCM800 camp. The variable slope is subtle, but noticeable. The cathode bypass/fat cap boost is similar; subtle but noticeable. To my ear it adds a hint of bass and opens up the top end. Diode clipping as expected has a slight volume drop when engaged. The rest of the knobs have a nice sweep range on them.

So the amp itself is complete and fully functional, but I'm not 100% done with everything. I still need to recover the headshell. That's going to have to wait a bit because I don't have a work area to do it right now. I cleared out and took down my old storage shed yesterday to make way for a new one. So all the stuff that was in there is now crammed in my normal workshop area (my garage) all up in the way.

Anyway, this was a very fun little project. Since everything was PCB mounted and wires were harness or spade connectors, it was akin to building a large pedal. All the components are labeled where they go on the PCB so it was "paint by numbers." The biggest "difficulty" was making sure I put the filter caps and tube sockets in the right orientation.

So if anyone is thinking about building an amp, but is nervous jumping straight in to a full build this would be a good place to start. I'd definitely recommend it. And it wasn't overly expensive. Depending on how much you spend on the donor amp it should come out to $600-$700 total, not including shipping/tax.