10 Parts You Need To Build Your Own Tube Guitar Amp

 

Building your own guitar tube amp doesn’t have to be scary.

In fact, running your riffs through an amp that you’ve built with your own hands can be one of the more rewarding experiences a guitar player can have.

In this article I’d like to introduce you to the various parts you’ll need to build your own tube guitar amp.  Beginners can easily become intimidated about how complex this project may be, so in this article I’d like to introduce you to the various parts you’ll need to build your own tube guitar amp.   Even if you’re an old hand at building amps and just want a basic checklist of parts, this article can help.

I’ll be giving you some example numbers and specifications so you can understand the kinds of numbers and considerations to make, but I won’t be listing out every single nut and bolt dimensions needed, because your project is specific to you.  Please refer to the specific instructions from your guitar kit or be incredibly confident in your skills to wing it. 

This article is for entertainment purposes only, and your personal safety while dealing with electricity is your responsibility.  Don’t make any decisions about interacting with voltage and electricity based solely on what you read here.  Be safe!

Tools Required

For this project you’ll need a soldering iron around 25 to 50 watts, resin core solder around 0.032 diameter, a variety of sizes of small spanner wrenches, and a couple of sizes of flat and Phillips head screwdrivers.

Cabinet

There are two main options when it comes to building your own guitar tube amp – you can either build a combo amp or an amp head.  The biggest differentiator between the two is that a combo amp contains both the amplifier and the speaker and an amp head only contains the amplifier and needs to be connected to a speaker cabinet.  To start off our discussion of the parts you’ll need, the difference between these two is that an amp head will need a much smaller cabinet than a combo amp, which needs a bigger cabinet by virtue of also containing a speaker.

For the purposes of this article I’ll be describing one of the more common styles of guitar amp kit – a Fender Princeton-style combo amp from the tweed era.  You’ll find guitar amp kits readily available in this style.

You’ll need a plywood or solid pine measuring around 16 inches high by 20 inches wide by 10 inches deep.  It’s important to make sure and measure and position the speaker and the completed chassis often as you build in order to make sure you are leaving enough clearance between the speakers and the transformers.

Chassis

A reputable parts supplier will be able to provide you with a chassis made to approximate a Princeton-style layout, which will work nicely for this project.

If you’re wanting to build the chassis yourself, I congratulate you for wanting to get seriously into the details of building this amp!  A company like Hammond makes a variety of steel and aluminum enclosures that are good for this – you’ll be looking for something around 14 inches long by 6 inches wide by 3 inches deep. 

Chassis that are supplied with a kit are already drilled and punched to spec, so feel free to save yourself some time here.

Tubes

For your combo amp, your tube setup will likely consist of something along the lines of:

  • 1 6L6
  • 1 12AX7
  • 1 5Y3

Speakers and hardware 

A good combo amp needs a good speaker.  Look for a 12 inch speaker from a company like Celestion or WGS.  An Eminence Legend gives a nice traditional Fender-style tone that helps achieve that vintage tone.  Along with about a foot of speaker wire, you’ll need a 4-pack of speaker mounting bolts and T-nuts if your cab doesn’t have a baffle already.

Output transformer

Much of the distortion of a tube amp comes from the output transformer, making it perhaps THE key component on your tube amp.  If you’re building your amp from scratch, you should be looking for a transformer intended for single-ended use, properly air-gapped, rated for approximately 15-watt output, with a primary of around 4k ohms to 6k ohms going into an 8-ohm secondary.

Power transformer

The power transformer converts the signal coming from the power tubes to the speaker.  

If your guitar amp kit doesn’t already come with a power transformer, it shouldn’t be too hard to locate a supplier with power transformers intended for use in a tube amp.  Looking for these specs:  

  • Primary: 120V
  • Secondary between 310V-0-310V and 330V-0-330V center-tapped
  • center-tapped 6.3V AC filament supply at 4A
  • 5.0V AC rectifier filament supply at 3A

Eyelet board, insulating card, and brass grounding plate

For assembling the circuit board, an eyelet board made for use with a SF1 and SF2 Princeton-type amp will work well for your project.  A good amp kit will provide these materials to you.

Resistors

I tend to lean more toward keeping noise lower by using a mixture of carbon composition resistors and carbon film.  Here are the specs you should look for:

  • 68k (1-watt)
  • 1M (0.5-watt)
  • 1k (2-watt)
  • 220k (1-watt)
  • 10k (5-watt ceramic)
  • 500-ohm (10-watt ceramic) (470 tends to be more common and works well too) 
  • 2x 1.5k (1-watt)
  • 2x 100k (0.5-watt, preferably carbon composition)

Capacitors

  • Signal:
    • 2x 0.022uF
    • 0.0047uF
    • 500pF
    • 0.47uF 400V axial
  • Electrolytic:
    • 2x 25uF/50v 
    • 16uF – 22uF/500V 
    • 16uF – 22uF/450V
    • 8uF/450V

Connection hookup wires

You’ll need around 2.5 feet of solid core cotton braided 20-guage black and white wire.  Cotton braided keeps together when near the excessive heat from soldering, and tends to be easier to handle because the covering can be pushed back to expose the desired wire length.

Miscellaneous parts

And finally, you’ll need a variety of miscellaneous parts to tie everything together:

  • A power cord nad power switch
  • A mini on/off/on SPDT toggle switch (boost/voice)
  • Quarter-inch plug for speaker leads
  • 2x 1M audio potentiometers
  • Fuse assembly
  • 1-amp fuse, 1.24” slow-blow
  • Screw-secured control knobs
  • Quarter inch switching jack for input
  • 2x quarter inch non-switching jacks for output
  • Pilot light assembly jewel and bulb
  • Ring terminal for grounding to the tube socket bolt
  • 3 lug terminal strip
  • nine -pin ceramic tube socket
  • 2x eight-pin ceramic tube socket
  • 3 rubber grommets

Conclusion

Now that we’ve taken a look at the components needed to build your own tweed-era Fender Princeton tube combo amp, I hope you are pumped! 

Now it’s time to get a guitar amp kit and start your journey!  Be sure to check out our list of the 5 best guitar amp kits.

Good luck!

 

 

 

Here are some additional resources I hope you find as helpful as I do: