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#G1TMH411

British Style 18W TMB Guitar Tube Amp Kit

Mojotone's 18-Watt TMB Amplifier Kit addresses a common mod made to a classic circuit, but with a few new flavors of our own. The TMB is based on the circuit used in vintage Marshall models 1958, 1973, and 1974 (more affectionately known as the '18-watters'). Marshalls were only produced between the years 1965 and 1967, but were highly sought-after for having massive sounding JTM-45-like tones in a smaller, more manageable package. Because they were produced in comparatively low quantities, these amps still remain a 'lost ark' today.

18-watters became popular studio amps for many players and were used, at times, by everyone from Gary Moore, to The Pretenders, to AC/DC. Over the years, some players have reported having no use for the amp's original tremolo channel and have opted to replace the tremolo controls with a 3-band EQ, since the original amps were only equipped with a single tone control for each channel. In the Mojotone version, we have done just this, only we have integrated the preamp from our British 800 kit (based on the original Marshall JCM 800 circuit) for a lean and mean, hot-rodded gain sound. We have also integrated a master volume control so this monstrous sound can be harnessed and used in any size room.

Two EL84s give the amp's normal channel a warm and round character which, when volume is pushed higher, begins to break up into a smooth grind perfect for blues rock and classic rock rhythm sounds. On the dirty channel, one can access screaming lead tones perfect for everything from dim dirty grunge all the way to saturated hair metal sustain!

If this kit shows as out of stock please check here for more information.

Please read our article 'Mojotone Amp Kit Building Primer' along with our amp kit disclaimer located in the Specs tab before buying this kit.
$710.00
Shipping calculated at checkout.
$5 U.S. shipping over $99
 Real support from real techs
Trusted by guitarists for 25+ years
SPECS

Weight: lb

* Note: If shown as out of stock, most amp kits ship within 2-3 weeks. Our team will contact you if we anticipate a longer lead time.

  • Class Type: A All Tube Amplifier
  • Output:~18 Watts
  • Circuit:1974 / 2204
  • Bias Type: Cathode Bias
  • Build Time:~6 hours
  • Preamp Tubes: ECC83/12AX7 (3)
  • Output Tube(s): EL84 (2)
  • Rectifier Tube: EZ81
  • Transformers: Power - 18W (7000018), Output - 18W (7000118)
  • Hardware: British 18W Small Parts Kit, British 18W Chassis, Front & Rear Faceplates, 10' Removable Power Cord

 Disclaimer: Some of the parts contained in this kit are subject to availability.

Mojotone reserves the right to change or substitute any and all of the parts contained in this amplifier kit without advertisement or notification to the buyer. Part substitutions made by Mojotone are guaranteed not to affect the integrity or operation of your amplifier kit. Time estimates listed are from start to finish. If you are new to tube amplifiers, additional time may need to be factored.

 When purchasing a kit from Mojotone, you will receive the following documentation.

1. Schematic

2. Wiring Diagram / Layout

If you purchase a kit from Mojotone and do not receive these documents, you can obtain copies by emailing tech@mojotone.com or calling 800-927-6656. The Mojotone staff is available Monday through Friday from 8:30 a.m. to 5:00 p.m. EST unless otherwise closed.

 Mojotone kits include the best quality parts that are available at the time of purchase. If a substitution is required, our team will use parts that are of equal quality to ensure the integrity of the kit build remains the same.

 Building a fully functional amplifier kit is not an easy task. Before building a kit, one should have the ability to properly solder as well as read and understand a schematic and wiring diagram. While we do our very best to ensure all documentation is current, the included documentation is meant to serve as an overall guide to building the amplifier. Simply following the schematic and wiring diagram does not guarantee you will have a fully functional amplifier. In fact, post build troubleshooting is a common issue across all builds.

 Our staff is available to assist with basic troubleshooting needs. There are plenty of online videos available that are helpful with most post build issues. Technical staff is available via email by sending a message to tech@mojotone.com. You may also call our sales team to discuss build problems, dial 800-927-6656 and press 1 for sales.

 Building a tube amplifier takes time, dedication, resources and most importantly... Skills! The experience of building an amp can come with some frustration, the reward of completing the build is definitely well worth your time. Please review the wiring diagram, schematic and manual (if applicable) prior to making your purchase. Mojotone will not accept any returns on amplifier kits and/or parts that have been assembled, soldered or modified.
DOCUMENTATION

This amp kit also comes with the following documents. Please feel free to view and/or download them: 

British 18 Watt TMB Schematic

British 18 Watt TMB Wiring Diagram

British 18 Watt Power Transformer Wiring Diagram

British 18 Watt Output Transformer Wiring Diagram

Overall rating: 4.785714 / 5 from 14 reviews.

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Reviews

Love it

"The jcm preamp makes it so you can really gain this thing up if you want to and with the master volume, at lower levels. Mid heavy, really cuts through. You can go from really great cleans to AC/DC (tnt) tones to early pearl jam and then you can push it hard with a pedal some early Metallica tones. It’s waaaay louder than I thought it would be capable of. Really versatile and lovely amp, great idea with the jcm preamp. A much more versatile addition for me than the 18 watt would have been. Great all around ‘er."

— Dave (5/5)

The Good, the Bad & the Ugly...

"I bought the British Style 18W TMB Amplifier Kit, and it turned out great! The Good: is the tone, it sounds awesome, everyone who hears it tells me so. I picked out grey/slate tolex and a Celestion speaker. They made the cab really well for me. The Bad: The kit had some incorrect parts (faceplates), and so they sent me the new ones. But they were wrong also. So then they sent me the really, true for sure correct ones ... and they were wrong AS WELL! Finally, they did in fact send me the correct plates. The Ugly: All documentation was wrong ... the paper wiring diagram did not match the on-line wiring diagram (in significant and important ways)! And the paper manual ... did not match the on-line manual! And the manual and wiring diagrams were also different from each other. And the on-line schematic was ALSO different. So, in conclusion, this amp is GREAT!! Really quiet (noise-wise), great old-school tone! Go buy one and build it today!"

— Teddy (5/5)

As easy as it gets, works great, sounds great!

"Ordered and built this in December 2023. The parts are very well organized and labeled. I was coming from wiring guitars and building pedals as a hobby. I was able to build it from the attached layout with no problems. To make life easier for me, I got extra wire (20 awg) for each color. Order of operations is essential. I wired the turret board first. Then I added the tube sockets are wired those next. Then the pots, ground lugs, jacks, and switches. Added the transformers next. Wired as much as possible before placing the turret board in, and did the connections from the turret board last. It will make your life easier to get a good soldering iron, I use an old Hakko with Kester rosin core solder. Have desoldering braid ready for any mistakes. The main thing to be aware is that extra wire is generally a bad thing in this application. Lack of organization is a bad thing. It’s easy to make shorts, which will sink your battleship."

— Heath M. (5/5)

Great sounding amp with a few flaws in the documentation

"Nice amp with a few documentation flaws. 1. The Wiring Diagram shows the Mains and Standby switches oriented in the wrong position, they should face up. 2. The earth ground at the AC jack should have a dedicated chassis ground not shared by any other component. It's unsafe the way it's shown in the wiring diagram. 3. The inputs, pots, and pre-amp section should all have a common star ground. 4. The ground for the can capacitor mounted to the top of the chassis should be connected to the star ground for the power section. 5. The lead on the indicator light to the AC jack is too short!!! Come on guys!!! 6. The 130 Ohm resistor and 25uF capacitor are shown too close together in the wiring diagram. The capacitor should be at least 1/2" away. Both components and several other resistors in the power section should also be raised off the turret board to allow adequate air flow. There is no mention of this in the instructions. When assembled correctly, the amp sounds great!"

— The G. (4/5)

Sounds amazing.

"Just finished this kit and just had to comment how amazing it sounds! I'm giving this a 4 star instead of 5 because it wasn't 100% perfect. 1/2 star shorted because: I was shorted 2 resistors from the kit, and I feel like an extra 6" to 1' of wire would be nice to have as I like to cut long and trim down. I had to get some tubes anyways, so I just ordered the resistors and extra wire from mojotone, no real big deal. The other 1/2 star is for the chassis not being 100% for this project. I had to enlarge 1 hole, and drill a couple new ones to accommodate the filter caps. The filter cap on the side is a little closer to the transformer then I'd like. The layout was updated as of November, and I feel like it was very well done as I've heard there were inconsistencies with that in the past, but I found none. Quality components. I would like to so an option to upgrade certain things like the input/output jacks. It sounds 10/10, dead quiet, great overdrive and great cleans!"

— Shawn (4/5)

I'm very happy with this kit!

"I'm not anything like an engineer or an electronics expert, but I pretty much understand what I'm seeing when I look at a wiring diagram and I'm able to follow it. Doing that with this kit was a real pleasure and the parts were great also. The chassis was build solid and true, and the wire was cloth fabric covered, which I really like. The Amp sounds great. I'd been warned that these can be noisy but have no trouble with that here. I'm very happy with this kit!"

— anonymous (5/5)

This might be the best sounding tube combo that I have ever played on.

"I just picked up a assembled version of the 18 Watt TMB 1X12 combo at the Dallas International Guitar Festival. It sounded good at the show. When I got it home, it really came to life! It takes pedals well too. This might be the best sounding tube combo that I have ever played on. It is well worth the money!"

— anonymous (5/5)

A Keeper

"Built this in Aug 2016. To me it is the perfect Celestion Alnico Blue delivery vehicle. Chimey clean with a Marshall roar on the TMB channel when pushed. The components are all top notch and the cabinet construction is phenomenal. Dinged the rating by a star due to documentation errors that were frustrating to work through, but this was over six years ago so hopefully they have been corrected. The TMB channel compares favorably with my '82 Marshall JCM800 4104 but without calling the cops. Make no mistake, though, the amp is loud enough for most clubs and drummers. There is a minimum loudness before which the amp can sound thin so I would not call this amp bedroom friendly."

— anonymous (4/5)

I will build this kit again!!!

"I'll have to say that this kit was THE most straightforward build I've ever done! Steve, Andy and the crew did a GREAT job collectively marketing this kit. The tones are amazing! I did alter the kit by incorporating their channel switching board (the relay-bashed one) and inserted an FX loop ALA Matchless Lightning style. (That passive FX loop works well with this amps level at the PI. You can insert the loop just after the channel switcher and have your time-based effects there for both channels. You will want to use shielded cable when inserting the loop and to-from the channel switcher. I picked up too much noise using unshielded wire.) I will build this kit again!!!"

— anonymous (5/5)

This amp rocks - both channels!

"This was my first amp build. It went very smooth. The schematic and diagram were of high quality. Both the TMB and normal channels sound fantastic. The components were of very high quality. My only recommendation for improvement would be to include the following documents: 1) schematic for the power transformer and output transformer, 2) a list of voltages and voltage test points along with target values. The only changes I may experiment with is adding some shielded wire to the gain circuit and trying some different pots/resistors for the master volume as the volume increase is a bit aggressive. I had a total 12 hours into the build."

— anonymous (5/5)

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