Build A Guitar Tube Amp

If you have decided to take the plunge and build your own guitar tube amp, please let me share my early projects/mistakes with you to help get you going in the right direction.  But first, be sure you really want to build your own:

  • You should be fairly handy around electronics already, and aware of the dangers inherent in high voltage tube electronics and the precautions to take when working on tube amps
  • You shouldn’t have the expectation that you will save money… unless your time is worth nothing at all you can probably do better purchasing a completed amplifier, even from the kit vendors, but certainly on the open market as used

All said, though, there is a lot of satisfaction in completing and playing an amplifier you built yourself and having the license to further modify/tweak/voice your creation to perfection… so let’s get started:

Stumbling Through My first Few Projects

My first project started as an AM radio, it had occured to me that this chassis and most of the components was quite suitable for an octal-tube-based Fender Champ-like single-ended amplifier and I wanted to hear the difference in tone between real tubes and the tube modeling in my Roland Cube amp… After studying some good tube amp books (see resources) I settled upon a plan and:

  • I fought with the old transformers (insulation turning to dust when you flexed the leads), used tube-sockets, noisy potentiometers and poor physical layout (working with the old radio chassis didn’t provide optimum placement of the major components for a tube guitar amplifier)
  • Found out that true point-to-point wiring isn’t the best choice for experimenting
  • I couldn’t find a non-microphonic old-stock pentode tube
  • The tone sucked… with hindsight I believe it was due to the underwhelming, un-branded, tiny output transformer, but I’ll probably never go back to check
  • Bottom-line, I learned a lot but it didn’t answer my fundamental questions about tube-tone because I didn’t end up with an iconic amplifier as a reference at the end of the project

I spent some frustrating evenings redesigning and reworking my first effort and then for my second major project I broke down and bought a kit that promised a clone of a vintage Champ amplifier.  Major findings included:

  • Saving a few pennies here and there on components isn’t satisfying when you end up investing a lot of time building the project and aspects of the end result look cheap (e.g. a plastic replacement for a ‘proper’ metal construction jeweled pilot light) or worse… sacrifice tone (e.g. cheap electrolytic capacitors)
  • I’ve grown a bit leary of un-branded chinese transformers that may not have even been hi-pot tested let alone certified by a safety agency; and who knows what laminations, etc. are used in the audio transformer?
  • Tiny chassis and cabinets aren’t the best choice for adding additional functionality to the stock circuit and very frustrating to work with
  • 8″ speakers and small cabinets suck tone… this amplifier sounds great when you plug it into a proper speaker & cabinet combination

Your First DIY Guitar Tube Amp Project

With the above experiences in mind it is time to summarize some considerations for the first project:

  • Simple project but not under-featured… something that will be satisfying and playable
  • Physically large for easy access, simplified assembly and room to modify
  • Well documented, well supported… not necessarily with user’s manuals and step-by-step construction guides, but rather by a community with active forums, or extensive web documentation, etc.
  • A complete kit of parts, no difficult sourcing of components
  • Good quality parts with the potential to upgrade them if desired… but moderation rules… you may want good value over extravagant components to minimize your downside if your project doesn’t come out well or you lose interest.
  • Standard sized chassis for easy sourcing of cabinets, or cabinets available from the kit supplier, or a desire, determination and ability to build (and finish) your own cabinetry

With the above given due consideration my third time was the charm! 

I recommend you search out a reputable supplier of tube-amp kits, and pick a model that suits both your taste in tone and a satisfying set of features for your first DIY Guitar Tube Amp!

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