Building a Monster: DIY JTM45 Replica with a few twists

Building a Monster: DIY JTM45 Replica with a few twists

As a pickup maker, it’s very difficult to provide great soundclips to showcase how the pickups sound, how it reacts to input from the picking hand and how it responds with the volume and tone knobs (and EVERY guitar is different).

Let me kinda twist this a bit – it is EASY to get great soundclips when the guitar is a good one, the pickups are great and you run into the computer via USB straight into Amplitube or Guitar Rig. That software is excellent in tone for recording and WILL sound like a mouthy Beagle if the pickups are junk…

That being said, the fact that it is software makes most of us think “yeah but… software or digital amps can fake a good tone… what about REAL tone…” – and I know what you’re talking about (I’m thinking the same thing). TUBES. We want to hear the FiftyNiners, SixtyNiners (and now we have SeventyNiners too! – think EVH) through a head or combo with hot tubes and a nice speaker. So did I.

So I set out to do the best I can come up with to provide my fellow guitar enthusiasts something we simply can’t deny. I set out to BUILD my own all-tube amplifier. First I looked on Kijiji and quickly realized that the budget I was working with would not get me the kind of amplifier I needed for this. I needed something with a history and a little prestige – at a price I could manage. There was only one option – build it myself.

And thus began the journey I kinda wouldn’t mind forgetting about but was SO worth the time and effort. Here’s how I built an amplifier to show the true potential of Romain Hand-wound Pickups for anyone curious about getting a set.

Sourcing a DIY Kit vs. Sourcing Parts and Schematics

I did some heavy research into this and came up with the realization that buying everything separately and piecing together my own kit was not worth the little amount of money it would have saved vs. buying a DIY kit that had everything you needed in one box.

Building a Tone Monster: Romain Amps DTM45 (JTM45 clone with some twists)

After looking at the various DIY amp kit sellers (Webber, Ceriatone, TubeDepot, Mojotone, Trinity Amps, etc.) I decided that the best reviews, price and quality of parts came from Mojotone, so I got their JTM45 kit. To save money, I got the kit without a head cabinet as well as without the tubes (which I later sourced at a better price from in addition to parts for a Master Volume mod).

The kit arrived and I couldn’t wait to dig right in! The above pic shows you the pile of stuff that was included in the box. I quickly went over the entire list of parts and components to make sure I had everything – and everything checked out so it was a go!

Building the Beast

The kit came with very little documentation. It came with a schematic of the entire circuit, and a wiring diagram. I am no electronic/electrical technician, so the schematic was about as useful to me as a sandwhich for a dead guy. So I had to rely solely on the wiring diagram and nothing else. There were plenty of head-scratcher moments, not gonna lie. That being said, the folks at Mojotone (I spoke to Steve and Vanessa) were nothing short of excellent and Steve replied very quickly to the two or three emails I sent him with a few wiring questions needing clarification.

The kit itself was clearly not the most beginner friendly project – but I got through it by taking my time, triple checking every connection I soldered and then marking it on the diagram as I went along. There was a few issues with the inputs and outputs in the diagram, either they were not 100% correct, or poorly drawn causing my to wire things wrong… luckily I’m not the first to build one of these so there was plenty of info found on several forums.

Building a Tone Monster: Romain Amps DTM45 (JTM45 clone with some twists)
Building a Tone Monster: Romain Amps DTM45 (JTM45 clone with some twists)

The End Result

After the amp was 99% wired up, I found a missing pin in one of the 12AX7 tube sockets… Mojotone was quick to have one sent my way for free so I got started on building the head cab. Long story short, I wanted to put together a quick box made from Pine sourced at Home Depot… but as I was building it, it was turning out much better than I had hoped yet the soft wood dented easily… the plan was to just paint it flat black, but it was now painfully evident that it would look like crap.

After a few nudges from friends saying I should just wrap it in tolex like other amps are made, I decided they were right. A quick trip to my local Fabricland turned up a nice piece of leather-like vinyl with a nice stretch that I figured would make it easier for a first go at tolex wrapping. I was right, and the end result was pretty damn nice!

Building a Tone Monster: Romain Amps DTM45 (JTM45 clone with some twists)
Building a Tone Monster: Romain Amps DTM45 (JTM45 clone with some twists)

So now there exists a Romain Hand-Wired All-Tube Amplifier. Here it sits as the Romain DTM45, a tube rectified Marshall clone powered by two EL34 power tubes and three 12AX7 pre-amp tubes. The only mod I did on this amp so far is add a Master Volume so I can play this thing in the house without getting flack from the neighbours. What I did is detailed a bit further in the Facebook post – essentially I took out the secondary Speaker output jack, threw the Presence knob in its place and put the Master Volume where the Presence knob was (because I’d use that more often than the Presence knob anyways). Down the road, I plan on a few other mods to make it less JTM45 clone, and more along the lines of what I’m looking for out of an amp. Might be another project to write about later on – stay tuned! Will be doing some YouTube videos with some FiftyNiners and such with proper recorded audio with a speaker cab mic’ed up.

This ’65 Marshall JTM45 clone amplifier turned out to be a blast, but a very time and mind consuming task, definitely not for the faint of heart or anyone inexperienced with soldering. It took me 4x the amount of time Mojotone advertises this project to take, and that’s totally fine. This is the kind of project you cannot risk rushing. You have to take your time, nobody’s racing you here. Take your time, triple check EVERY connection, mark it down, then re-check everything again before plugging it in – there’s enough current going through this sucker to stop your heart man! The best tip I got was – if you have to get your hands inside after it’s been turned on (but is now unplugged and drained of voltage), use your right hand. A shock to your left hand goes straight to your heart. That’s scary enough a thought on its own. Proceed with caution at your own risk – if you must build one of these things.


If you want to read a more detailed photo documentation of this build, I have a TON of pictures and descriptive captions on Facebook at this link

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