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Konstantin Raudive Diode Circuit Diagram

The Original Diode that Fostered EVP Communication for Raudive

Tim Woolworth, 2014
Konstantin Raudive Diode Circuit Diagram

Konstantin Raudive Diode Circuit Diagram

We are in a new age of paranormal exploration using technology and this is partly due to Konstantin Raudive introducing EVP to the world with the English publication of his book Breakthrough: An Amazing Experiment in Electronic Communication With the Dead (1971). Nearly every day someone visits this site looking for more information on Raudive as more and more people are looking towards the original research to find out how we arrived at the methods of spirit communication that we use today.

This is a very good thing – it means that people are willing to look past the uneducated para-science that ghost hunting television show “investigators” spout in order to sound intelligent and make ratings. There once was a time when EVP was examined by physicists, electronics engineers, psychologists and biologists as a serious science. Paranormal entertainment has removed all hopes of examining spirit communication as a serious science. We are left with a handful of self-sustaining organizations who still seek answers about how communication occurs with the Others; but as with any self-sustaining organization, they are completely reliant upon how much money they can bring in from members and they almost never receive substantial grants to upgrade equipment or hire new talent.

So that brings us to the topic of this article – the Raudive Diode. Here at ITC Voices we get a few searches on Raudive and his Diode daily and I realized that the diagram was not available on this site even though I have sent PDF’s of the chapter to many colleagues to learn from. The Diode was one of the first successful modifications to standard EVP equipment and hopefully someone out there will find this information useful.

The Raudive Diode is basically a very simple, low power AM crystal radio with a short antenna. This radio was connected to the aerial antenna of a regular radio in hopes that voices would come through. Raudive met with success recording voices through this method although the Raudive Diode was only used for a brief period of time in the mid-70’s; shortly thereafter people moved on towards making the Psychophone invented by Franz Seidl.

What the Raudive Diode demonstrated is that a carrier signal helped electronic voices come through and subsequently ushered in the use of white noise during the formative years of EVP recording. Other researchers who have tried the Raudive Diode have met with minimal to no success as powerful radio stations still come through.

Naturally, now that we are in a day and age when people are caught up in a paranormal frenzy and will buy anything that promises results, there are several folks out there who now make the Raudive Diode commercially and typically sell them to the public in an attractive plastic box. I have purchased two of these boxes and have recorded no EVP voices yet through them. The first thing I noticed was that these are standalone boxes that do not hook up to a radio as Raudive intended – so no wonder they don’t work! These are basically the AM crystal radio only and they do not modulate a signal as they did when Raudive used them.

Commercial Raudive Diode #1

This is the first commercial Raudive Diode that was available on the market for ITC research. Out of the box, it is an attractive little device that offers two antennas and a microphone that works with a really small push button on the side of the device. Opening up the Raudive Diode, you can see it has a wound antenna and a basic circuit with a switch for the microphone. Using the microphone is impossible because you have to pick up the device to use the switch. The output is a mini-line (1/8″ plug) to go into your recording device.

Commercial Raudive Diode #2

The second Raudive Diode I purchased is an even simpler device and it is currently available as well through a paranormal equipment supplier. This device simply has a telescoping antennae, a modern Raudive circuit inside, and a mini-line output for your recorder.

Regarding the original Raudive Diode, I will quote here verbatim what was written in Raudive’s book.  It should be noted that this section which contains the write-up on the Raudive Diode is found in the appendices of the book and it is not penned by Raudive himself, rather by a collaborator named Alex Schneider, who was a Physics Professor at St. Gallen University, Switzerland. He later went on to become the president of the Parapsychological Association of Switzerland.

All quoted content from:

Raudive, Konstantin. Breakthrough: An Amazing Experiment in Electronic Communication with the Dead. Trans. Nadia Fowler. Ed. Joyce Morton. New York: Taplinger Publishing Company, 1971. 340-342; 353-354.

All notations to follow the quoted text.

p. 340-342

Raudive’s “play-ins” were carried out by the following four methods. Other researchers have varied the arrangements in non-essential details without attaining any notable improvements.

The Microphone Method: The microphone is coupled up as for any usual recording.

The Radio Method: A wireless receiver is coupled to the tape recorder exactly as is done for the recording of any radio programme, preferably via the “diode-cable” (2). A small piece of wire is inserted into the aerial box in order to keep out any long-distance reception. Raudive finds a spot in the medium wave band in between two stations where background noise is as blank as possible. Other investigators choose the moment when a transmitter starts to beam out the carrier wave (6) just before beginning to transmit a programme or else they select a slow-speaking lecture programme in which the pauses between groups of words are so considerable that call-signs can be interspersed. A carrier appears to  be necessary, or, at any rate, desirable.

The Auto-Transmission Method: A small transmitter (a metering transmitter) is coupled directly to the aerial box of the receiver, in order to provide the voices with a carrier wave that is free from heterodyne oscillation and interference. The voices thus recorded by Raudive are relatively soft, but they are at least against a homogeneous background noise, and this is an advantage when monitoring. As an experiment, the medium wave band carrier was modulated by a pure 1000 Hz note, but this was found to interfere, as was to be expected. It might, however, be practical to modulate using a noise-generator, since a number of voices sound as though they were constituted from the homogeneous noise-spectrum by some physically unexplained process of selection. Perhaps a completely pre-determined series of sounds could be made to serve the same purpose, acting, at the same time, as an inductor for the contact (7).

The Diode Method: A short (6-10 cm long) aerial is used to give a more or less broad-banded signal, which is rectified by diode and fed directly by a cable to the radio or microphone input of the tape recorder.

This provides the clearest voices, but the interference caused by near-by strong wireless transmitters must be reckoned with. However, one can listen to their programme during the recording or reproduce them separately on other tape-recorders. Variation of the aerial length or the use of filters for particular strong transmitters can provide a better electronic performance. Weak and distant (especially foreign-language) transmitters cannot be received, particularly in the daytime.

The screen can be easily manufactured by the investigator himself, and Diagram 1 shows the circuit used in the earliest experiments. Experience with varied circuits has shown that the elements are not critical, though the rather old type of diode OA 81 could well be replaced by a more modern one. Diagrams 2 and 3 relate to the reception of higher frequencies (8).

The screens must be effectively covered, and may be earthed independently. T and X (1) had great success with a braod-banded pre-amplifier in front of the diode (9).

Konstantin Raudive Diode Circuit Diagram

Konstantin Raudive Diode Circuit Diagram

The tape-recorder is used by all methods for the registration of the voices, but the latter can also, under special conditions, be heard directly. Registration on tape is, however, necessary for precise analysis and study. The beginner misses most of the voices when the tape is played back, and this is why not every radio listener and recording tape enthusiast discovers paranormal voices. There are, however, grounds for thinking that voices on tape are not noticed or falsely interpreted by the casual listener, more often than is generally suspected.

p. 353-354


(1)Three other researchers are named as T, S and X.

(2)The circuits are described at length in the working instructions of the apparatus involved. In nearly every case, two different machines can have the playback transferred from one to the other.

(6)For an explanation of the term: high-frequency carrier, see under “Critical Judgment of the Procedure.”

(7)Ideas for this paraphysical component may be found in the abundant literature on the magic of sound. One could, of course, also try to do the same thing with the other play-in methods.

(8)T had success with Circuit 3, but Circuit 2 is only a blueprint.

(9)T uses a commercial two-stage valve amplifier for shared aerials, to which the diode screen is coupled.

Hopefully the information provided in this article will shed some light on the famous Raudive Diode and provide you with the necessary knowledge to either construct one yourself or purchase one commercially.

For more information regarding Konstantin Raudive, please see an earlier article on this site.



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