This is where we left off last time. The sockets are installed, heater wires soldered, and turret board complete and in the chassis. Now it was time to get this amp finished.

If you have followed my build progress, you may have started to see a pattern here of over-preparation and study before each task. However, as we will see later, this paid off.

Here I've laid out all the remaining components on the build diagram and am ready to start making solder smoke.

As the smart folks on the AX84.com website recommend in their build guides, I highlighted each and every solder joint, switch, and component on the build layout as I completed them in the chassis.

Shielded wire insulation tends to shrink back off the solder joint if not protected from excess heat. I once again used hemostats as heat shields, with excellent results. Note the shrink wrap over the clear insulation on the shielded wire.

On Ramiro Silva's website, he included a PDF scan of the impedance selector switch specifications, with some hand-written instructions on how to wire the switch (shown in upper right of this photo).

I had some problems understanding this at first, and thought I'd provide a diagram for future builders (see drawing on right).

Click the image for a larger version. Wiring is pretty simple, once you realize that you need to jumper pins 3 and 5. It doesn't matter if the switch is turned upside down, just number the pins as shown, and wire accordingly.

PINOUT (as wired):
Switch Up = Pins 1-2 (4 ohms)
Switch Middle = Pins 4-2 (8 ohms)
Switch Down = Pins 6-2 (16 ohms)

I added an octal tube using "eyeball engineering", not good practice for a real engineer like me. However, it worked fine. Here is a close up of how I wired the octal and noval together in parallel.

Another detail of the octal to noval wiring.

I saw some questions on the AX84 forum regarding wiring of the tone pots. Here is a good view of one way to do it. This worked well for this build.

Detail of switch wiring. From left to right, these components are (1) power cord, (2) fuse holder, (3) power switch, and (4) standby switch. Note that the green wire is the incoming ground and is attached directly to the chassis. I used one of the power transformer bolts for this (see photo below).

Top view of completed amplifier, facing front to back. Click for large format photo.

Top view of completed amplifier, facing back to front.

I built a current limiter to reduce the chance of burning up the amp at startup. A table lamp is plugged into the left socket, and the amp in the right. If the lamp glows brightly, there is a short in the amp. It was very dim with power on and standby off, and a little brighter with standby on...the amp was perfect!

Here she is at "first light". Hmmm, no speaker? No problem, as this amp is wired with a shorting jack and is "safe" without a speaker connected. Just like my Super Reverbs.

I hereby declare this amp complete. Next comes various tests with different speaker combinations, and some good music cuts.

Experienced builders probably won't need this, but I made a small gallery of additional wiring photos. As a rookie (this is my first amp build), I appreciated every shot of High Octane design builds that I could find. Also, feel free to use my contact form to ask any questions. I answer all email as quickly as I can and enjoy talking about amp builds and restorations.

CLICK HERE FOR A GALLERY OF AMP WIRING PHOTOS

(NOTE: THIS IS A VERY LARGE PAGE)