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'66 Brit-74X 18W Amp Kit

'66 Brit-74X 18W Amp Kit

'66 Brit-74X 18W Amp Kit

Item # 10732
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'66 Brit-74X 18W Amp Kit

About This Item

Leave your half-stack at home
Born in London, the original 1965 circuit of this compact bluesbreaker earns its living every night gigging in clubs on both sides of the pond.

Launched in 1966 (and originally produced for just two years), this amp quickly became a low-wattage holy grail. This is a stripped down blues machine: two channels, one tone knob, no master volume. Buckle up and go where this gritty beast takes you! It comes with a footswitch to kick in the onboard tremolo.

Just listen to "Middle of the Road" by The Pretenders for an example of what this tone machine can do. Our Brit-74X will get you this sound at a volume that won't result in eviction. Its rich overdriven tone set the standard for early British blues-rock. Roll down your guitar's volume for a cleaner tone, add some tremolo for depth and movement that you can't get out of a digital model.

StewMac has lovingly recreated this timeless amplifier in our '66 Brit-74x Amp Kit. This is one of our Icon Kits: modern reproductions of vintage classics.

Take your amp building skills to the next level with this kit. The ‘66 Brit-74x is a perfect place to get serious about amp building. This is an involved amp and will be a fun challenge to complete. If building such an iconic amp sounds hard, don't worry.

We've gone to great lengths to make sure this kit has the best step-by-step directions in the industry. With hundreds of full-color photographs and illustrations, these instructions make this an easy, fun and rewarding project.

It comes with all the parts you need to complete this project in just a few weeks.

  • The cabinet interiors are genuine 3/4" North American Pine
  • Superior craftsmanship on the tolex covered exteriors with perfectly aligned seams
  • Premium quality hardware
  • Top-shelf EL84, 12AX7, 6CA4 tubes and vintage spec Heyboer transformers to give your amp the perfect vintage tone
  • High-quality period-authentic resistors, CTS pots, reproduction mustard caps, and Switchcraft jacks for their authentic tone and a lifetime of trouble-free use
  • Authentic epoxy turret boards just like the ones used in the original vintage amps
  • British-voiced 12 inch speaker

Need Help? Our trained staff is standing by!
If you get stuck, don't worry, we're here to help. Our knowledgeable team of amp builders are just a phone call away. Our team is deeply involved with building these amps and can answer any question you have.

You don't need a shop full of tools either!
The great thing about these amp kits is they only require a few relatively inexpensive tools. We've got everything you need to build this amp right!

Build and use this amp internationally!
This amp works wherever you are! This amazing amp has a 240 volt winding on its transformer. This means that if you are outside the USA, you can still build this amp without needing an external step-down transformer. You can also run it at 240 volts to capture the original tone designed in London in 1966.

Amp cabinet dimensions
Height: 20" (50.80 cm)
Width: 24" (60.96 cm)
Depth: 9" (22.86 cm)

WARNING: Cancer and Reproductive Harm -


Product Instructions

'66 Brit-74X 18W Amp Kit Instructions

The new StewMac '66 Brit-74X will be a blast to play through and even more fun to build.

Customer Reviews

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  • 4.67 average rating from 3 reviews
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Amazing sounding amp worth the arduous process of building


Verified Buyer

This build was long and difficult for me. There were issues with missing and out-of-spec parts, slow support communication due to COVID-19, inconsistency with some of the instructions and what seems to be a design issue that I ended up having to resolve on my own. I was emotionally tested every step along the way and I'm shocked to arrive at a place where I'm writing a positive review.

Even with all the trials and tribulations I have to give the kit five stars because I absolutely love this amp. I had hopes that it would come close to replicating the legendary tones of the British 60s and my high expectations were exceeded by the sound of it. And StewMac did stick with me through the entire process - which is something considering how much support was needed.

My advice for other relatively novice builders:
1) Make sure you are confident in your soldering technique, especially for turrets. There are web resources that can help.
2) Test all parts before installation rather than taking them on faith.
3) Know that the step-by-step instructions are more accurate than the schematic in this case.
4) There was a design issue that cropped up in my build that required a resistor between the left lug of the normal tone pot and turret #20. To see if this is an issue in your build I recommend measuring resistance between turrets #20 and #21. If you see continuity you have a problem. Mine was solved by adding 140 ohms of resistance. This may not be an issue with all builds, but it was with mine and it was difficult to diagnose and resolve.

To sum it up: StewMac should get their act together about this kit and it's problems before shipping any more of them out. That said, StewMac made it possible for me to build mine and I can't honestly rate it as less than five stars considering the sound of the finished project.


Amazing sounding amp but kit needs some attention to detail.


Verified Buyer

I have previously built the Brit 800 and Deluxe Reverb kits from Stewmac so I have gained some experience in the process. This amp really has it all tone wise and falls nicely in the middle between the two previous builds I completed. The speaker is really nice and sounds amazing. The only issues I have with this kit were missing parts and the cabinet back panel was incorrect.
I did not receive the instruction manual but used the online PDF manual until I received the paper copy. The instructions are very detailed and easy to follow. Other parts missing were speaker wire, a washer on one of the toggle switches, not enough yellow wire and the indicator light mounting nut would not thread onto the plastic threads. I also had a defective 1M pot and had an issue with the input jack wiring. I was having a strange ground loop noise between the tone pot and channel 1 jack. I finally wired the jacks differently from the manual's instructions since I didn't get a definitive solution from Stewmac on how to fix the issue. Double-sided tape would also be nice to keep the plastic faceplates down on these marshall kits. I used some epoxy glue on mine. Another issue was the back chassis mounting wood panel not fitting flush against the top of the cabinet. The cabinet manufacturer changed their cabinet design but didn't allow for the differences when the holes were drilled for the chassis which caused a 3/4" gap between the top of the chassis and the cabinet. I finally asked to have some tolex sent so I could just build my own panel since I didn't want to wait for the cabinet builder to correct the issue. Matt and Tommy at Stewmac were very responsive with these issues and sent out replacement parts quickly, but it's still frustrating to have to start and stop when you get into the project. I would give this kit 5 stars if they get these issues worked out. It really is an awesome sounding amp at a great price and would encourage anyone to pick this kit up.


Challenging, but fun and rewarding kit!


Verified Buyer

This kit is the first amp I've ever built and though it took me quite a bit longer than the 12 hours suggested, everything turned out well with very few problems. The experience was fun and now I've got an amp that gives me a really unique sound. There's very low noise, on par with commercially produced amps. Another really small, but nice detail was that the back panels on the cabinet have threaded inserts instead of bare wood screws. I love it when builders do that, especially with soft woods.

As some background, I've built pedals and other electronics before, so I'm used to soldering and checking over electronics, but you definitely don't need to know anything about schematics or designs to build this.

The biggest trouble I had with the amp was that there was too little wire included, but StewMac's famous customer service fixed that quickly by sending out more. I also had a few questions about some voltage readings near the end and Matt, the amp kit's designer, was the one who responded to my questions and let me know that everything was going fine.

If you're looking to build an amp, this kit is great. The instructions are really thorough, the parts come in really nice, compartmented containers, and the final product is just flat out fun. This model is definitely more complicated than some of the other, smaller amps, but I was able to do it despite never having built one before.