If you are the owner of a vintage piece of mobile radio equipment, chances are your equipment is equipped with a plug-in
radio vibrator. Such a mechanical vibrator allows for low-voltage DC coming from a vehicle battery to be converted to HT
voltages as needed for tube radio equipment.
Radio vibrators were used from the early 1930s up to about 1965. After that, DC to DC converters for mobile tube
equipment were designed using the newly available semiconductors, first by using early germanium power transistors,
later also silicon power transistors were used.
This was done up to the 1980. After that, mobile radio equipment did not use tubes anymore which also eliminated the
need for DC to DC converters.
Examples of equipment in which radio vibrators were used:
• Car radios (6V or 12V)
• CB radios (6V or 12V)
• Early ham radios (6V or 12V)
• Some portable tube radios (mostly 2V)
• Mobile radio telephones (6V, 12V or 24V)
• Mobile public address amplifiers (6V, 12V or 24V)
Military radio equipment:
• HF transceivers (6V, 12V or 24V)
• VHF/UHF transceivers (6V, 12V or 24V)
• Mobile & portable receivers (2V, 6V, 12V, 24V)
|RVB-1 Solid-State Radio Vibrator Circuit
radio vibrator fail. These failure modes can have multiple causes.
Mostly radio vibrators fail due to the vibrator contacts becoming dirty, corroded or burned-out. Less likely failure modes
are mechanical failures (broken reed spring) and/or drive coil failures.
One way to fix the contact failures is to open up the vibrator case after which the contacts can be cleaned using fine
abrasive paper. (Mostly this case consists of an aluminum can crimped onto the bottom insulator holding the terminal
Cleaning the vibrator contacts is only possible as long as the contacts have not worn away from excessive sparking; if the
latter is the problem your vibrator is beyond fixing.
As you might have noticed after doing this, the contact cleaning job is never a lasting fix. The vibrator very soon will fail
The reason is that most vibrators were filled with an inert gas by the manufacturer. After opening the case, the contacts
will be exposed to oxygen from the air causing them to fail again very soon after contact cleaning. Another problem is that
after sanding, the gap between the contacts becomes larger, resulting in a smaller duty cycle for the generated wave
form as well as an increase in contact bounce (the latter causing additional sparking)
So you will likely end up cleaning the contacts again soon, shortly after your first contact cleaning job. Buffing the
contacts again using sandpaper can only be done so many times; the contacts will eventually have worn away too much,
preventing proper operation.
Maybe you have bought one of these, only to find out that such a NOS vibrator actually does not work!
As it turns out, almost any vibrator will suffer corroded contacts over time, even when actually never having seen usage.
As mentioned earlier, vibrators were not produced any more after 1965 which means that anything you find on the market
today (either used or NOS) is close to 50 years old, and in most cases much older than that.
We have found that the cause of such failures involving NOS vibrators lies in the rubber seal that the vibrator has at its
base, as well as the foamy rubber that is used to suspend the vibrating mechanics inside the cylindrical case.
This rubber material has gassed out over the years releasing sulfur. This in its turn will corrode the silver vibrator
contacts over time. (Keep in mind that the original designers had NEVER envisioned their radio vibrators to last for more
than 50 years – they clearly did not have collectors of vintage equipment in mind when they designed their product!)
As a result of all this, functioning radio vibrators are a dying-out breed; even the NOS ones that have been stocked in
warehouses for all those years will most likely not work anymore.
found in abundance; capacitors can have their innards replaced with modern types to maintain their vintage looks. But
the radio vibrators, that is an entirely different story.
keep it running anymore! What is a vintage radio aficionado to do to keep his or her vintage tube equipment running?
The answer: Our PeKo RVB-1 solid-state radio vibrator board. This board was specially designed by us to replace a wide
variety of radio vibrators, WITHOUT the need of any modifications to your vintage equipment. The RVB-1 solid-state
vibrator board is designed to be a direct drop-in replacement to many different mechanical vibrators.
This was accomplished by designing the RVB-1 solid-state vibrator such that it can replace a wide range of mechanical
vibrators types, as well as allowing for a large operating voltage range (5V to 30V DC). It uses modern high-voltage, high-
speed MOSFETs having a very low ON resistance, and as such it requires NO heat sink. Also, the board is small enough
to fit in any existing vibrator can, even the narrow European types (Philips brand)
Last but not least, the RVB-1 board emulates the exact same wave form as the mechanical vibrator; both in terms of duty-
cycle (Off time during crossover) as well as operating frequency (115Hz and 250Hz are selectable).
PeKo can do specialized versions for different operating frequencies and/or duty cycle requirements, as all these
parameters are programmable under firmware. Just let us know your requirements when ordering the RVB-1.