Mojotone Custom 100 Guitar Tube Amp Kit


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SKU: G1DR1031
Weight: 30 lb
Sale Unit: Piece

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Please read our article 'Mojotone Amp Kit Building Primer' along with our amp kit disclaimer located in the Specs tab before buying this kit.

The design was a labor of love that started in a garage in New Malden, England. It quickly grew in local popularity, and made its way to the stage behind big names like the Who, Pink Floyd, Jethro Tull, the Moody Blues, and Manfred Mann. The legendary DR103 is synonymous with big, clean, and powerful.

Skilled amp builders, try your hand at recreating this sonic icon with our Mojotone Custom 100 amplifier kit.

The kit comes with everything necessary to build a working unit, including resistors from Ohmite and Vishay, Mojotone Dijon capacitors, Heyboer transformers, Belton tube sockets, and potentiometers by Alpha.

Also included is a full-color wiring diagram which provides a faithful road map of all the right angles and mil-spec techniques which were documented from studying two original examples from the early seventies.
  • Class Type: AB All Tube Amplifier
  • Output:~100 Watts
  • Circuit:1970-1972 DR103 Custom 100
  • Bias Type: Fixed Bias
  • Build Time:~8 hours
  • Preamp Tubes: ECC83/12AX7 (3) & ECC81/12AT7 (1)
  • Output Tube(s): EL34 (4)
  • Rectifier Tube: None - Solid-state Rectified
  • Transformers: Power - Hiwatt 100W (MOJO784), Output - Hiwatt 100W (MOJO983)
  • Hardware: Mojotone Custom 100 Small Parts Kit, Custom 100 Chassis, Front & Rear Faceplates, Octal Base Clamps, 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.

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

Custom 100 Schematic
Custom 100 Wiring Diagram


Warehouse Sessions Featuring This Product

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Ratings & Reviews

2 reviews

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4/12/2024 6:14 pm

Quality Kit and Customer Service

by Nic D.

Just as impressive as the quality parts is the phenomenal sales and after sales customer service. The amp layout diagram is clear and all parts are clearly identified. My build worked first shot (however I did triple check my work as I was building each section). No hum or hiss. Tons of headroom giving super clean to clear crunch tone. I know it's been mentioned on many forums but I will repeat how well it takes pedals.
Really enjoyed this build.

7/18/2022 7:41 pm

A quality, quiet, responsive amp!

by Reiley C. -

A quality and fun build! Sounds amazing! Honestly an amazing amount of capability with pedals. Plenty of headroom, even with E34Ls over EL34s.