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How to build "B battery" AND basics on "B battery" eliminators to run vintage radios

HOW TO BUILD "B Battery" basics on "B battery" eliminators and run vintage tube gear

There are many ways to get high voltage for projects or vintage radios/amps and tube gear. Quick searches
usually lead to great but semi-complex and expensive to build circuits for this purpose. To eliminate the
needed B+ voltage found in many vintage portable radios and amplifiers you need to get the required voltage.
This ranges from about 45VDC to 150VDC+ A few techniques require only 1 transistor. I developed one which
required only 4 components! 1 transistor, 2 resistors, and a transformer. It was tricky but if done right it works
great for voltages up to about 150V. I was even able to run a plug in clock radio loudly with it when I designed
and developed it from a much more complex circuit as a basic 'inverter' to convert 12Vdc into 110V or so pulsed
DC which will work just fine in simple transformer-based power supplies like those found in clock radios.

It was similar in operation to circuits found in older low power flash power supplies like those found in disposable
cameras. This is a source that with current limiting would work for some stuff. One could use this to produce
150+ volts but the actual current draw is limited since the flash capacitor no matter how large will eventually
discharge unless it's charger (the circuit) is powerful enough to run your device in a balance. This could work
for many things like small portable radios that need very little current. But they may produce radio interference
depending on the oscillator circuit used and receiver type/frequency. If you turn up the volume too high it will
drop in voltage far faster then it can be recharged. This may be a great option as a 'jewel thief' circuit for getting
50v from a 3 or 6V filament battery (2D cells for example) so you can run your vintage tube radio off of just the
filament batteries. I plan to build one of these and post plans soon from scratch but one could use a flash unit
if you found the right one and modified it correctly. DRAWBACKS ARE these flash circuits must be harvested and
modified for voltage and current output if you want to use them to run 45-50v devices! --NOT TO TRY IF YOU
DON'T KNOW WHAT YOU ARE DOING! Even a small flash circuit can be DEADLY since it is hooked to a HV capacitor
(and they always are)--this is how the Xenon flash blubs work. A potential of about 150 to 1000VDC+ is placed
across the Xenon filled tube (currents as high as 100amps or more! for a fraction of a second can be produced)
--then a small 'trigger' wire (usually a wire around the flash tube a few mm from one side) is given a smaller 'trigger'
charge causing the capacitor to discharge across the tube in a very bright flash of white light. Kinda like a micro
lightning bolt, the Xenon gas ionizes far better then air and thus gets very bright. The process happens very fast.
These circuits have drawbacks from interference to limited current draw and modifications needed to drop the voltage
properly so that you don't fry your vintage gear!

There are also simple to build so-called 'vibrator' circuits which one can build from a modern relay and transformer combo. These can be useful for very basic low current experiments but end up producing a very hard to get rid of hums and LOTS of radio interference! Not a good system for most applications especially if it's not fully in a Faraday cage--it becomes a small spark-gap transmitter which could cause serious radio/TV interference (yes even with cable, dish and sometimes digital) Very simple to build but it's also not a very efficient way to do things since lots of energy is lost in the process and eventually relay contacts will fail from arching. Back in the 1930s-50s these were commonly used for everything from car radios to power supplies for transceivers. Instead of a relay, a replaceable 'vibrator' in a tube-like case switched the contacts more smoothly and used special materials with a large transformer and capacitors. Some of the first uses for transistors were to eliminate the need for inefficient vibrator HV circuits such as in CB radios that still
used mostly all tubes. You could build one of these with some jumpers and a relay--but there's a far more easy way!

FIRST OFF THIS IS VERY DANGEROUS!! Like all high voltage devices. I can't stress this enough, as unlike a
Tesla coil (even somewhat large ones) the amperage (current) is NOT at even remotely relatively safe levels--
which is around 0.1-5ma or less. 9V batteries shorted produce 100s and 100s of Milli-amps (ma)! --with ANY
type of 9V battery (even the dirt cheap ones). I am not responsible for anyone who tries this and does not
respect it. 9V batteries can produce more then 1 amp and if they are chained in series (easy to do since one
battery will clip right onto the other). The drawback here is high current--AND high voltage dangers--but this is not a
drawback if your application needs it (transmitter/bigger amplifier). A chain of just ten 9v batteries produces about
90-100Volts with current levels at as much as 1000ma (1amp or more!) Yes this will run light bulbs, but NOT
much else. Most things like chargers for cellphones and laptops or TVs require AC for switching/transformer
based power supplies and or voltage multiplication circuits. Yes you can run a light bulb and a very small number of plug
(NON-FLORESCENT non-CFL) light bulbs with 110V from 9v batteries as this could damage home devices! AC and
DC current differences are very important! You don't want to fry your cell-charger! A few older devices allow for
DC to be used (especially some vintage radios) which were built for use on ships and other places that used 100-110vDC
power but most of these took too much power for 9v batteries to handle.

This does not mean they are weak or safe! Look up Wikipedia 'Electric shock' for details--EVERYONE SHOULD
DANGEROUS and POTENTIALLY LETHAL to humans according to the test I had to take to become a Technician.
So you do the math--this is not to be taken lightly and should be treated like a huge frightening 60hz transformer
and capacitor chain of the type you find in tube final power amps or ham radios. A 9V 'pile' can produce enough
current to run lots of stuff, at least for a while and without the complexity of interference of other sources.
There is also ANOTHER DANGER. During the course of my experiments I had an accidental short on a 7 battery
pile to drive a magic eye tube. This went undetected for just a 1min or so and the batteries EXPLODED with a
loud pop and chemical smell. Some wires and areas were hot enough to start a fire! 9Volts may be small--but
they are no small matter! That's why many stun-guns can produce about 50-100kv that can drop a large man
powered off just one 9v battery!

If you did come in contact with high DC volts you could die or suffer permanent nerve damage! (loss of feeling or
movement) due to high voltage discharge. This can happen with HV capacitors as well, used in HV supplies for
amplifiers, flashes and all sorts of things. When I was in middle school a kid got in serious trouble for thinking
he could use this idea to make a zapper. I tried to warn him about how dangerous this was, he did not listen and
his friends are lucky to be alive thanks in part to how many times he shorted out the batteries to impress people
thus draining them.

Just put together a chain of 5 batteries for 45volts. Easy to do since 9v connectors use the same contacts as the batteries so they can be snapped together in a chain since (-) and (+) are always separate shapes. So, 9x5= about 45v-50vdc (45vdc is the old B+ battery standard voltage!) depending on the battery quality you may get a few more or less. Most 9v actually produce nearly 10v when new. You may want to current limit the system for safety reasons with a
resistor/capacitor combo (rated for the voltage/current needed-use Ohms law). 9v batteries in a pile produce plasma when arching that is very bright showing how dangerous they are! (Somebody showed us all how to do this on UTUBE)
They put out considerably more power then the old B batteries. Be sure to include a bleeder resistor to discharge any
capacitors used if you want to keep stable for a transmitter test or something and never leave a 9v pile laying around
where someone may find it and not understand how dangerous it is!

In theory, there is no limit to how many you can chain together other then your budget and your sanity! More then
200=1800+volts which is more then enough to run many amateur radio power tube transceivers at least for a time
depending on how many watts they need. I used this to power an all tube portable 1950s AM radio recently with
nothing but nearly dead 9V 5-8volt measured--and was able to pickup the local AM stations very well and hear them
loudly through the speaker.

There are some great but complex schematics on line which require lots of parts and others that don't. The 555 timer
is a good chip to learn how to use as you can pulse any frequency into a transistor and drive a transformer making for
a very stable output. Great if you have the experience, time and money to build. However--this is what to do if you
just want a basic supply for a tube amp or radio--to test it or use it for a while. Good luck!

--G.Beasley (Mostly Macros Photography)


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