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Single-Ended EL84 Stereo Tube Amplifier Kit


Your gateway to custom tube audio can't be any easier. 


The Exordium is a DIY kit for builders looking to get started with a great sounding tube amplifier in a compact and sleek physical design.

Everything you need for quality sound in a compact size.

The Exordium includes components carefully selected so that you will have a great sounding tube amplifier at a reasonable size and cost. Operating up to 4 watts per channel, it is not a powerful amplifier, so it is recommended for smaller listening spaces and speakers that have high sensitivity. If you are looking for an entry point to tube audio without spending a lot but also not compromising on quality, this is the kit for you.

Speaker Impedance:  8 ohms

Output power:  4 watts per channel

Total Harmonic Distortion (THD):  1.8% at 1 W (1 kHz)

Frequency Response:  40Hz - 20kHz (~1 dB)

Input sensitivity:  825 mV

Dimensions:  8.75" wide x 11" deep x 7" high

Additional circuit and component details:  The Exordium is a single-ended design using a 12AT7 dual-triode driver tube and EL84 (6BQ5) output tubes. It is wired to run in ultralinear mode for the best balance between power and distortion, but can easily be modified to run triode-strapped. It includes a Hammond power transformer (made in Canada), EdCor output transformers (made in USA), and I include either JJ Electronic tubes (made in Slovakia) or Electro-Harmonix tubes (made in Russia). The chassis is hardwood and aluminum, hand crafted and finished in the USA.


Instructions written and illustrated for humans.

You will not just build, you'll learn.

With an electronics kit, you should never have to settle for a frustrating experience trying to interpret poorly-written instructions and hoping that all the parts are going together correctly. The Exordium has extensive step-by-step instructions, illustrations, schematic and layout diagrams. Even more, it includes an entire circuit explanation so that you are empowered to truly understand how your amplifier works, and explore future designs of your own. You don't need anything other than a few tools including a soldering iron, and you do not need to know how to read a schematic.



Customer from Quebec


At the beginning, I was very sceptical about the result I could expect from a DIY ampli without a PC board and a ton of capacitors. However, I was very interested by learning how vacuum tubes work and the possibility to put all that in practice with the building of the Exordium. Perry answered all my questions and gave me the insurance that I would have a good backup if I had any issue during the building of this tube amplifier. This is not an easy work to solder all those components and point to point wiring, but it is feasible. The result is very good and was way above my expectation. This amplifier is not very powerful, but the quality of the sound is very good. I was able to drive my old speakers (Camber 0.7t) without any issue and those speakers are rated for 10 watts to 75 watts. Perry is already sharing his user manual online which was a big winner for me to start this project. I highly recommend it. Follow the instruction and you will get a big smile in your face at the end when you will be playing one of your favorite tunes.


Au début, j’étais plutôt sceptique du rendement que pourrait donner un petit ampli DIY sans PC board et une tonne de petits condensateurs. Cependant j’étais vraiment intéressé par la compréhension des tubes à vide et la possibilité de mettre ça en pratique avec la construction du Exordium. Perry répondait toujours à mes questions avec patience et me donnait l’assurance d’avoir une bonne ressource à consulter si jamais j’avais des problèmes durant la construction de mon ampli. Ce n’est pas un travail facile de souder tous ces composants et de faire les branchements point-à-point mais c’est faisable. Le résultat est excellent et au-delà de mes espérances. Cet amplificateur n’est pas très puissant mais la qualité du son est excellente. Je suis capable d’alimenter mes vieux Camber 0.7t sans problème malgré le fait qu’ils soient conçus pour une plage de 10 watts à 75 watts de puissance. Perry partage déjà le manuel de l’usager sur son site en ligne et ce fut un gros facteur déterminant pour me lancer dans ce projet. Je le recommande fortement. Suivez les instructions et à la fin vous aurez un gros sourire quand vous ferez jouer votre pièce préférée.

Customer from Georgia


Excellent instruction manual that is easy to follow and as a bonus includes sections on basic electronic theory, how tubes work, and a description of the circuit.
I was surprised at the more than adequate listening level even with my low efficiency (85 dB) Harbeth Monitor 30's.

Customer from Georgia


Fired up and ran clean first time plugging it in, good instructions and good sound.

Get started today.

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