Well, the victorian ages are finally over. The internal combustion gasoline engine has replaced the need for steam and coal. People have devices in their houses to talk to one another and we no longer burn oil to read at night. These were also the times when we understood electricity well enough where we could really start building the unimaginable. Although nixie tubes were created in the 1950’s, neon signs have been around since the early 1900’s. I have always had an interest in these interesting little tubes and decided to give them a period correct home, albeit strange.

This project started out from a kit from tubeclock.com. The only other thing I really needed was a proper clock case which eBay gladly provided for around 20 dollars. The only other things I needed were a few hand tools, clamps, and some wood scrap. As you can see from the picture to your left (click to enlarge), I cut two straps of wood and glued them to the inside of the clock. This served as the mounting point for the tubes. After that, it was a matter of lining everything up nice and plum before I drilled two mounting holes. To finish the project, I smoked the glass to give it a patina’d look.

All in all it was a pretty simple and fun project to bring some nixie tubes into my home. In total the project was less than 200 dollars with most of it being spend on the tube kit. More pictures can be found in this flickr album.

What is a nixie tube?

As you can see from the picture, its a metal apparatus that sits inside a glass tube (removed in this photo) that is filled with neon gas. When an electrical charge is applied to one of the ten digits, cathodes, they glow. They come in many different shapes and sizes and can be controlled in a number of ways. In this case, they are used to display the time. To read more about how they work and where they have been used check out the nixie tube wikipedia article. Thanks to the evil mad scientists for the photo.

Simply put, a basic vacuum tube is much like a light bulb. In a light bulb, negatively charged electrons travel through the filament colliding into the surrounding atoms but in a vacuum tube the electrons jump off the filament onto a positively charged plate called an anode. This type of vacuum tube is called a diode. What it does is convert AC to DC. This basic idea has been around since 1904 and later perfected in 1907. Since then many variations have come and gone but the same basic concept hasnt changed. The tube you see to the right is an RCA 5692 triode tube from the 1950’s. My newest amp requires three of them on the input side but more of that later.

Over the past 100 years they have appeared everywhere in world of science and technology. They were in televisions, radios, radar, tanks, phone networks, stereos, and really almost everywhere. They eventually became the backbone for the first computers. Today, most tubes have been replaced with much the much smaller and modern semiconductors we see today. Nowadays they are often found among radio enthusiasts, high-end or vintage stereos, and in guitar amps.

So whats so great about vacuum tubes in an amplifier?

It really depends on who you ask. This has been a long drawn and heavily debated issue ever since the first solid-state stereos were introduced in the 70’s. For me, I like all things vintage. Especially vintage technology. I love their simplicity, their nostalgic character, and the attention to detail you get from a hand built piece of equipment. For just the engineering reasons alone I love them. All that being said, they sound wonderful! They are warm and rich and deep. The sound can be so real and the stage so perfect that Neil Young’s harmonica sounds like its next to you and Stevie Nix is singing in your living room.

For me, its a really the entire experience; the charm and character that they bring along with a good piece of vinyl is amazing. The solid-state guys say that the sound isnt right due to the electron cloud inside the tube which is responsible for amplifying the sound. The analog guys claim its reality, its lifelike, and a lot of music was recorded this way since the beginning. Either way, I seem to enjoy them.

What is an RCA 5692 tube and more importantly, what is a triode?!

Lets not worry to much about the RCA tube you see above and look more at what a triode itself is. There were so many different ones built from so many countries over so many years it can be dizzying. All that really matters is that they are like cars. Some were well built and some were not.

To the left is a basic diagram of a triode vacuum tube (thank you Wikipedia). The main difference here between a diode and a triode is the grid surrounding the filament.

Remember that the filament is emitting negatively charged electrons that are picked up by the anode, but in a triode tube, there is a grid or screen in between. By applying a negative charge to this grid you can control the amount of electrons that will contact the anode.

There is a lot goes into the circuit topology the dictates how to charge the grid but thats another story for another day. The two amplifiers I currently have are both powered by triodes, both on the input and output side, but their design differs in the way the tubes are implemented.

A few months back I started sketching out plans for a do-it-yourself record player. Since then, not much has gone on due to my friend the electronics expert being out of town so I decided to source some parts. I turned to a Chinese company called diyhifisupply.com. China you say? Well, over the past few years China has really become a key player in the DIY world of high fidelity. They are creating high quality components a great prices from the platter you see below to oil filled caps, tubes, and other various parts.



This platter was laser cut out of 40mm thick acrylic at a final diameter of 298mm. Its truly is a beautiful piece of work. The markings on the platter are for timing it with a strobe. Below is a photo of the bearing that I ordered along with it. It too is a very nicely machined piece of work with a self-oiling design using rifles to push the oil back up to the bearing. When everything is all connected together it turns very smoothly.

For a long time now I have been interested in vacuum tubes. I love their simplicity, sound, and the fact that the design hasnt changed since the early 1900’s. They also were used as transistors in early computers before the solid state transistor was invented. 50 years ago it would take an entire room of these to power a computer with less memory than a Casio wristwatch.


Anyway, this is a beautifully hand made oil-filled-cap integrated amplifier than runs in 80-watt Class A/B ultra-linear mode and 40-watt triode mode. I have it fitted with a set of Russian Electro-Harmonix tubes, the power coming from two sets of KT88’s. The sound is quite crisp with little to no hum or background noise which is surprising considering tubes are known for these issues. This paired with a set of Kef iQ5 floor standing speakers are wonderfully crisp and clean, especially with vocals. Now, to fix the weak link, the 5 dollar garage-sale bought record player. More to come on the DIY record player later.

In my quest for a great sounding stereo and my annoying need to build things I have decided to build my own turntable. Luckily my friend Mark, microelectronics expert extraordinaire, will be teaching me the finer points of circuitry. I will be handling the sourcing, fabrication, and/or assembly of the plinth, bearing, and tonearm. This is a very exciting project for me because I have a limited knowledge when it comes to creating my own circuits. This is one of the last nagging things that I have been dying wrap my head around. More to come as the project progresses. As always I will delving further into the details on my wiki.

Essentially, all I did was take a bluetooth headset, one of those little ones that fits in your ear, and put it inside a retro looking phone. This is only a prototype, but eventually I will make a more advanced one, this is quite rudementary. The red button you see is the call button. It is used to pick up and hang up the phone. It is also used for voice dialing. The power cord is attached to the phone cord through the back of the phone’s base. Then the power travels up the stock line to a 1/4″ stereo jack right to the base of the phone for easy removal. Thats it. Instant bluetooth handset. It works quite well for being my first go at it. The sound is good and so is the range. The total porject cost was barely $75 dollars.