Introduction: Custom Audio Amplifier

Picture of Custom Audio Amplifier

I had recently built a Nixie Tube clock kit, and from it, I wanted to work with some more cool looking tubes.My dream started to come to life when I was offered an opportunity to build an audio amplifier. There is no substitute for moving needles and bouncing bars of a volume visualizer. If I were to try building this amplifier, instead of it being just another black box with inputs and outputs, I was going to make something everyday people could also appreciate.

Step 1: Supplies

Picture of Supplies

The main supplies needed for any amplifier are as follows.

-Preamplifier; this is the device that controls your inputs and volume, most are standard rca inputs, but if you want an old record player you will need a phono preamp.

-Amplifier; the device that will actually make the sound louder.

-Protection Board; not necessary, but can prevent either poor wiring or popping from reaching speakers.

-Power Supply; creates the correct voltages for your system.

-Speakers; alternatively you could use headphones.

The parts I used are a 2 channel 100w per channel amplifier board. It's black PCB looks quite pretty I think.

I also have a 27v power supply to power the amplifier board as well as the other eccentricities.

The preamp board I got has a blue lcd sceen with an Ir remote and its own power regulator which needs a 12v center tapped transformer.

the 120v ac wall power needs a receptacle and a fuse to prevent shorts.

2 sets of binding posts to insert the speaker wires into.

Step 2: Inspiration

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I was super excited to see what I could make into an audio amplifier. There were few things that were certain. One was that it should include vacuum tubes or nixie tubes in some way, the second, is that I wanted a futuristic look to compliment the old tubes in it. I Really like the way the electronics look in the show continuum, with the clear plexiglass and blue leds as well as some grey metal to compliment it all. I decided to try to match this feeling in my design. I made a couple of quick sketches down in a notebook, to see what might be a good idea. I eventually settled on an angled board with plexiglass to display it, as well as tubes next to it to compliment it. I've decided to go with two magic eye tubes, as well as some circuitry that will allow them to act as left and right channel music visualizers. I like the idea of grey stained wood rather than metal, to add a more rustic look. I modeled all of the parts I have in solidworks, in order to try so spacially see where everything will go.

Step 3: Initial Building Phase

Picture of Initial Building Phase

The first build of the system I did was in dollar store foam board. This is a simple quick and easy solution to get a test build up and make sure everything works. With all the parts inside, I tested the system to make sure it worked properly. This is a great technique, as I learned my lcd was upside down, and that my tubes were too close to the preamp board screws. once I had sorted those things out, I could get to building the actual case.

Step 4: Final Building Phase

Picture of Final Building Phase

From the foamboard template, I started to make the real case. The case was made with poplar boards stained grey. The entire case is screwed together, and the circuit boards are fastened either from underneath, or from the inside. To make the joints disappear, I simply went over them with a thin black line. It adds to the design, and hides glue joints all in one simple way. To make the plexiglass front, I cut two thin pieces on the table saw. I then used the back side of a hack saw blade to smooth out the rough cuts and give them a frosted edge look. They were epoxied in place. The hexagon pattern under the amplifier PCB was made from cutting a pattern in some painters tape and spray painting the piece. Afterwards I peeled off the tape and used spray adhesive to add a sheet of paper as a light diffuser. I used long 4mm bolts to space out the plexiglass above the amplifier, giving plenty of airflow. The rest of the case is screwed together using 3mm bolts.The last thing I did was find some frosted white tubing to cover the cables that had to go to the amplifier to make them look like a water cooled computer. All the electronics were transplanted from the foam case and tested again to make sure nothing got detached.

Step 5: Light It Up

Right now all I have is a neat looking amplifier, Now I need to make it really glow. I Have a few ways of doing this. The tubes themselves have a red glow from the heating element, and will have a cyan beam to visualize the music, as well as a blue led underneath. the power button has a blue led ring and the LCD screen also has a blue led backlight to it. I wanted to make a diffused plexiglass, and edge lit acrylic look, to give it that futuristic effect. The inside is filled with blue led strips that act as a light box and shine through the front panel and the diffuser on the top, as well as making the wiring sleeves glow a little bit. I also added a strip underneath to give an underglow to the amplifier, making it easier to see its size in the dark. The only thing that annoys me is one tiny green led on the actual amplifier board that glows, and since it is surface mounted, I cannot remove it easily.

Step 6: Conclusion

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I spent a lot of effort trying to get a very polished looking amplifier and I am pleased with the results. It fits very well with my nixie clock, and I think I will extend this design concept into more of the projects I create, as it is very stunning and unique. I hope that this has maybe cleared up what is involved in building an amplifer and encourages you to try and build your own. It has been my first project that dealt with mains voltage, and 230v DC for the vacuum tubes. I only managed to shock myself twice which is why I now wear an anti static strap and make sure everything is unplugged at all times. I think I will upgrade the amplifier by installing a bluetooth module or a phono preamp for turntables, but as for now I am very satisfied with it.

Comments

pbrown239 (author)2017-05-31

That's a cool set up. Is there a link to a wiring schematic and parts list. i would love to do something similar using back lit VU meters, a sub out and an A, B speaker switch.

Swansong (author)2017-05-23

That's a fun setup :)

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Bio: Average intelligence kid with above average ideas, just trying to make the world a better place.
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