Mojotone 50 Watt Bass Amp Head Kit

1 Review
$599.99 to $824.99
Weight: 30 lb

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This kit has a lead time.  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.

Designed with a "keep it simple" mentality, this kit is meant for the bassist in need of a great sounding, all tube amplifier, without the excessive weight. At a meager 30 lbs., this bass amp is a shining example of maximum efficiency in the tube amp world.


In keeping with this simplicity, the control panel is as straight-forward as they come. The "Gain" knob controls how much the pre-amp section is driven, the "treble" knob adjusts the level of the high frequencies in the signal, the "bass" knob controls the lower level frequencies, and the "master" knob controls the overall output volume of the amplifier. In addition to these controls, there is a "Mid-Shift" control that shifts the mid-range response from a flatter sound to a more "scooped" mid-range response.


Using the "gain" control, one can take this amp from pristine cleans all the way to powerful over driven and gritty bass tones. With 2 KT66 power tubes, 2 12AX7 pre-amp tubes, and a solid state rectifier, this bass amp is sure to deliver what any bassist needs out of an amp, without all the heavy lifting.

  • Class Type:AB All Tube Amplifier
  • Output:~50 Watts
  • Circuit:AB763 / M45
  • Bias Type:Cathode Biased with adjustable potentiometer
  • Build Time:~6 hours
  • Preamp Tubes:JJ ECC83/12AX7 (2)
  • Output Tube(s):JJ KT66 (2)
  • Rectifier Tube:None - Solid-State Rectified
  • Transformers:Power - 45 Power (7020300), Output - 45 Output (7021300), Choke - (MOJO777)
  • Speakers:None
  • Cabinet:Mojotone Small Head Cabinet
  • Hardware:Mojotone 50W Bass Small Parts Kit, British 45 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

Our beginner level kits such as the tweed champ and tweed deluxe include a manual. If you purchase a kit from Mojotone and do not receive these documents, you can obtain copies by emailing 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 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.

The following documents are included. Please feel free to view and/or download them:

Mojotone 50W Bass Amp Schematic
Mojotone 50W Bass Amp Wiring Diagram

Ratings & Reviews

1 review

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2/17/2021 1:33 pm

I am delighted with the final outcome.

by anonymous

So while there are some things that could have been improved, I am delighted with the final outcome.

Shipping was slow and the kit when arrived had couple wrong parts, back plate that was too short, and the chassis needed a few holes either expanded or moved. Mojotone was very responsive and quickly shipped me the needed parts. I adjusted the chassis. There was also a couple runs of red wire in the diagram, but no red wire in the kit. Maybe the intention was to use the extra length from the transformer, but there wasn't enough reach for that. I just used some that I already had.

Instructions were light. If you've never wired tubes before, be prepared to spend some time reading up on heater wiring and how to avoid hum. A single page of additional instructions that covered that and where to wire your grounds to avoid the risk of a ground loop probably would have been enough for me. Again, not really covered, but I ended up using the green and black for the heater wiring and solid wire I had around plus the green for ground. Outside of the red, there was just enough length.

Having said all that, I really do like the kit; nice components, measurements were always very close to stated values. It looks fantastic and sounds even better. There's just a hint of 60hz hum until you turn the standby on and then it's just smooooooth bass sound. I really just had no idea how good a tube amp could sound. I've got it hooked into a tc electronic 2x10 combo where I added an extra jack to bypass the built in amp. It's like night and day. I can't imagine how good it would sound with a nice cabinet.