Build a Cigar Box Battery Box for Tube Radios




If you are into building and playing around with tube radios like I am, you have probably have a similar problem as I do with powering them. Most of the old circuits were designed to run on high voltage b batteries which are no longer available. So I decided to make a universal battery box to run my radios on. To stick with the old school DIY radio builder style I decided to use an empty cigar box to make it in. You can buy or get for free empty boxes at drug stores and tobacco shops. DON'T SMOKE! Also beware this thing well produce high voltage current, probably not enough to kill you but it might give you a good jolt or even burn you, so take the appropriate precautions when building and using this device.

Teacher Notes

Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.

Step 1: Materials


1- Cigar box, larger one big enough to hold all of the batteries.
1- 4x D-cell battery tray
4- d-cell batteries
8- 9volt batteries
6- spring clips(fahnstock clips)*
6- #6 machine screws*
6- #6 nuts*
6- solder terminals*
- 22 gauge solid copper wire
- glue
- electrical tape
- double sided foam tape

*These parts can be replaced with 6 binding posts if you like, I already had the clips so I used them*


- Wire cutter and striper
- Soldering iron and solder
- Drill and bits
- Screw driver and pliers

Step 2: Installing the D-cell Holder

For the A-Battery, heater batteries, I used a 4 cell D battery holder. Start by gluing the battery tray into the cigar box, I used some medium CA to glue it down, you can use what ever works for you. I decided to make the battery box more useful and tap the battery pack in the middle so that I could have either a 3volt A-battery or a 6volt A-battery. To do this simply solder a length of wire to the wire that connects the two rows of D-cells together and cut it long enough to reach the front of the box.

Step 3: Assemble the High Voltage B-battery

Warning- This can be dangerous, do not over heat the batteries or short them out, they might explode!!!
2nd Warning- You are essentially creating a 72volt battery, you know how a single 9volt battery well give you a little buzz when you stick it to your tung? This well do a lot more then that, be careful, don't stick it to your tung either :P

Start by arranging the 8 9volt batteries in two rows of four with the terminals alternating, see first photo, this is to make connecting the batteries in series easier. Now using electrical tape, tape the batteries together. Strip the insulation off of some 22 gauge solid copper wire. Cut the wire into short pieces and bend the ends at a right angle forming a staple that hooks into the terminals. Use these pieces of wire well be used to wire the 8 batteries in series, see third photo. After all the wires are arranged solder them to the battery terminals. *Solder the terminals as quickly as possible and do not do both terminals on a single battery one after the other, do one terminal and goto another battery and do it and then come back and do the other terminal. This is to reduce the amount of heat applied to the battery as heat well damage the batter, possibly causing it to explode.

Cut three pieces of wire, two red one black, long enough reach from where you are going to attach the B-Batter pack in the box to the front where the terminals well be. Strip just one end of each of the wire for now. Solder the black, negative, wire to the negative end of the B-Battery. Solder one of the red wires to the positive end of the B-Battery, this well be the +72 volt connection. Solder the other red wire to the wire connecting the 5th and 6th 9volt batteries together, this well be the +45 connection.

Attach the B-Battery pack to the inside of the cigar box, I used double sided foam tape for this so that when the batteries wear out I can easily remove it and replace it with a new battery pack.

Step 4: Adding the Terminals and Final Assembly.

Drill six evenly spaced holes in the front of the cigar box to attach the Fahnstock clips or Binding Posts, which ever you are using. Use a machine screw and nut to attach the clip to the front of the box and a solder terminal to the other side at each of the holes.

Solder the negative lead of the D-cell battery tray to the first terminal, left most. Solder the 3volt center tap to the second and the other end of the battery tray, +6 volt, to the third terminal. These well be the A-Battery connections.

Solder the negative wire from the B-Battery to the 4th terminal, solder the +45 volt wire to the 5th terminal and finally solder the +72 volt wire to the 6th terminal. Use some pieces of electrical tape to secure the loose wires to the inside of the box.

Use a pen and label the connections on the front of the box.

Done. Notice there is a lot of excess room in the box, this would be a good place to store wires to connect the battery box to what ever you are powering and also add more batteries. If I was to do this again I would have gotten two more batteries so that i could have had a 90 volt B-battery as well and also I might in future add a single D-cell holder to have a 1.5 volt A-battery as well making the battery box even more usefully for powering homebrew radios.

Be the First to Share


    • Made with Math Contest

      Made with Math Contest
    • Multi-Discipline Contest

      Multi-Discipline Contest
    • Robotics Contest

      Robotics Contest

    14 Discussions


    7 years ago on Introduction

    may i recoment building a circut that is adjustable between 60-250V
    i have that kind of circut build and use it for testing/building radio's televisions and amps

    and also for the reformatation of electrolitic caps


    8 years ago on Introduction

    i have an old Philco floor model tube radio. it comes on but omits a loud Humming sound. can ya' tell me how to eliminate the noise? thanx

    1 reply

    Reply 7 years ago on Introduction

    replace the caps that are behind the rectivier

    so the firsth caned caps after the rectivier
    if you give the type number of the radio i can help more


    9 years ago on Introduction

    its a really nice project!

    i wish it was as easy to find these boxes here in Brazil as it is there... i'd built a tube amp inside one of these!

    may i suggest rechargable battries though they are twice as much there better in the long run also this way uses snap connectors


    10 years ago on Introduction

    Can you please post schematics for this? I found a free PDF of the book you were talking about, but it only had a wiring diagram, and not detailed schematics. I would like to try this while I wait for the output transformer for my other tube amp to come. Please post something. Thank you.

    2 replies

    Reply 10 years ago on Introduction

    The battery box? Or the little two stage amp that I show it powering?


    Reply 10 years ago on Introduction

    Hey there Ohm! That wouldn't be a bad Idea! Why not an instructable for the two tube amplifier in a cabinet that matches the Antique Chrystal Radio Instructable? You might have to add a fan, but that wouldn't be hard. Besides, don't you think that the power box needs a 12v supply as there are tubes out there with 12v heaters / filaments? You might have two inputs for the amp, one Hi-Z the other Low-Z, that way one could run the output of the Chrystal Set into the Amplifier. You might also produce an instructable for a matching power box.


    10 years ago on Introduction

    Very nice! I always wanted to do this to build a higher voltage portable supply. I am curious, though. In step 3, could you use 9 volt snap-on battery terminals with their leads shorted to join adjacent battery terminals (rather than soldering wires)? I think I have tried this way back when and it worked: The distance between adjacent battery terminals is the same as each battery's own terminals, and so, the snap-on terminals will fit. No? How long would a battery like this last? What is the typical draw for the B+ of tubes?

    1 reply

    Reply 10 years ago on Introduction

    Yes you could certainly use snaps instead, I just decided to solder them as they were not going to be used for anything else. As for battery life, the 9 volt batteries well out last the D-cells used for the A supply. The tubes in the little amplifier I am showing with it the plate current is only about 5mA at idle, so not much at all. It works good for powering single tube radios ect.


    10 years ago on Step 3

    It's possible to daisy-chain 9-volt batteries to make a series string of any length. It's not as compact as two rows, but it's quicker than soldering. A dc-dc converter powered by D cells would be cheaper in the long run, but that's another project.


    11 years ago on Introduction

    Unfortunately I didn't that any photos or anything when I made the amp. The amp comes from the book "The Boys Second Book of Radio and Electronics" by Alfred P. Morgan, if this guy was still around he would probably make some good Instructables, his projects are very well described with some great line and pencil drawings. The only thing wrong with the circuit is it needs a 2k ohm resistor across input to load the output of a crystal set or regenerative radio. If you are into crystal radios and such like that I would highly recommend getting the book as it has quit few other cool radios and even a Geiger Counter too, you can usually find one on Amazon. Just don't pay the $100 for one that some people seem to think they are worth, I got all the ones in my set for less then $40 each.


    11 years ago on Introduction

    Very Nice work ! I have a few home brew radios and always have a power supply problem ....maybe you can do one on the amp next since I need one to go with some of my crystal sets that look like they have come from the same era


    11 years ago on Introduction

    Okay, this is one of the most coolest looking things I have ever seen! Looks amazing, +1 rating. (added to favorites)