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How To Build A QSC1850HD Coil Device

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Presentation Transcript
How To Build A


Coil Device

This presentation is designed to help individuals construct what’s referred to as a QSC1850HD coil device. The makers of this presentation are not medical practitioners and do not endorse the use of this device for medical purposes nor do they make any claims. The QSC1850HD coil device is an experimental piece of electronic equipment. The sole responsibility for the end use of a QSC1850HD coil device rests solely with the individual who builds it. The information presented in this PowerPoint presentation is not copyrighted and may be reproduced by anyone free of charge.

Let me begin by saying that there are far more electronic literate individuals than myself. So why am I the one creating this program? Simply because I am NOT an electronic literate individual. I know a few basics, but even now, after building my own coil device, I still don’t know the whys and wherefores of a lot of this device. All I know is that it appeared to be an impossible task for me to complete, and yet with the help of some very knowledgeable individuals, I was able to be successful.

My intent is to put together a simple plan with all the information in a single place, so that anyone with the will to build one of these devices can. May God bless you as you move forward with your project.

Just what exactly is a QSC1850HD “Coil” device?

A QSC1850HD “Coil” device is an experimental machine that uses an amplifier and a capacitor bank in series to create an AC (alternating current) EM (electro-magnetic) field which can be tuned to a given frequency. 

Completed QSC1850HD “Coil” device in a cabinet.

Frequency Generator


QSC1850HD Amplifier

Capacitor Array Switches

If you are going to build a QSC1850HD coil device, the first thing you need to decide is how you want to house it. I decided to put mine in a cabinet. I chose this method because my wife and I don’t have a room we can dedicate to a large amount of wires, and equipment. I needed a way to store all of the equipment that would look good, even if the cabinet had to sit in our living room.

Using a cabinet is not the only way to house a coil device. But let me show you what I did. If you don’t have the tools to build the cabinet, but you do have a room to dedicate to your coil device, simply skip this section.

I started by purchasing a 4’ x 8’ piece of ¼ inch Luan plywood from a lumber company. I then used a table saw, (a simple skill saw would suffice) to cut it into the sizes I wanted. My cabinet is 16” deep, 24” wide, and 36” high. My cabinet does not have a back on it.

I made two pieces 16” wide by 36” long for each side, and one front panel 24” wide by 36” long. I used a 1” x 4” pine board to strengthen the cabinet. I also used a ¾” piece of plywood (particle board would work too) for the floor of the cabinet. The piece of plywood in the bottom is more for strengthening the cabinet in general. Nothing heavy actually rests on the lower part of the cabinet.

Picture of My Cabinet

16” x 36”

Side panel

24” x 36”

Front panel

I cut the plywood with 45 degree angles to make a flush corner. This is not necessary. Edges may be butted up together.

Bottom shelf of ¾” plywood or particle board.

These terminal boards will later be referred to as the “terminal wire.” The terminal wire is basically where all capacitors connect to a single wire that goes from there to the coil.

Casters to move cabinet easily.

Bracing on top of cabinet. I used liquid nails and finish nails through the ¼” Luan plywood. Screws would work as well and would be even stronger. To finish the cabinet, I will put a top on it made of another piece of ¼” plywood.
Where the pieces of plywood came together, I used small strips of ¾” x ¾” pine. I ripped these on a table saw from the 1” x 4”s. You would not need to rip down the pine. You could use the wood as a 1” x 4”. In fact that would make the cabinet even stronger.
After I nailed and glued the basic cabinet together, I turned it on its back and marked out where I needed to cut a hole for the QSC1850HD amplifier. You will notice in the next picture that the amp is spaced out away from the cabinet with two pieces of wood, one on each side.

I did this because the QSC1850HD amp is apparently made to be recessed into an audio cabinet of some kind. I didn’t want my amp sunken into my cabinet, so I purchased a small wooden decoupage plaque for 99 cents from a craft store and cut it in half. It was ¾” thick and brought the amp out just enough to make it fit well.

Measure how far the bottom of the hole in the front of the cabinet is from the floor of the cabinet and then nail or screw a 1” x 4” pine board across the back for the amp to rest on.

I screwed a small block of wood between the wall of the cabinet and the amp to keep it from moving as well.

The QSC 1850HD amplifier is a new generation amplifier with rugged design. The founder of our QSC 1850HD Yahoo group visited the QSC factory and talked to the man who designed this amp. In parallel mode, this amp works great. I purchased mine on eBay. They are also available new with factory warranties from several on-line electronics companies for around $500.00.
The next thing I did was to cut out for my multi-meter. I chose to purchase a bench model Fluke 8012A. I did so because it was a true RMS multi-meter and it was cheap on eBay. I understand that true RMS is not all that important, but it is better to have it than not to have it in my opinion.

Another option for a multi-meter is to purchase a hand held model. The one I would have purchased had I not found my Fluke 8012A was the Wavetek Meterman 37XR. I was told by a Fluke representative that Meterman test equipment is owned by Fluke and is their “lower end” testing equipment.

I like this meter because it is true RMS and can measure inductance. Later on when you build your coil, you will need to measure its inductance. I purchased an LC meter which measures inductance and capacitance for around $42.00 from a company on line. The bottom line is purchase what best suites your needs. With a meter that measures inductance all you will need to do is touch each end of the coil lead with your meter’s leads and you will know your coil’s inductance. It’s VERY simple to use.

If you don’t want to purchase an inductance meter, you can determine your coil’s inductance by using your capacitors when your device is finished. The next few pages will tell you how to do that.

This picture shows how to measure a coil’s inductance in Millihenries (mH) with an L/C meter. An L/C meter is a meter that measures inductance where L stands for inductance measured in millihenries (mH), and C stands for capacitance measured in microfarads (uf). If you purchase the Wavetek Meterman Test Tool 37XR, it will measure inductance like what is shown here by simply putting the dial on mH and connecting the two leads. To get a more accurate measurement, you can follow the steps listed on the next slide.

7.84 mH coil

LC Meter

Set to 20 mH range.

Meter connected to other lead of coil.

Meter connected to one lead of coil.

12 gauge speaker wire.

To find your coil’s inductance in mH (millihenries) using your capacitor array, begin by flipping on your 16uf capacitor switch. Now set your frequency generator so it puts out a 435Hz signal. This frequency should be close to a resonance frequency for a coil between 7 and 8.5 mH with a capacitance (uf) of 16uf.

The next step is to turn up the amplitude (volume) control so the amplifier’s yellow lights come on. Your gain knobs should already be turned all the way to maximum when you do this. The yellow lights tell you that you are now pushing an audio signal through your coil. Turn the amplitude (volume) up until you get a reading on your multi-meter (assuming it is already connected across one set of resistors as show in the next slide) that is around 0.30.

An exact reading of 0.30 is not important. You just need to get the power up a little so you can get a more accurate reading with the next step. It could be 0.26, or 0.35. Just get it up in that range.

Once you have a reading on your multi-meter begin changing the frequency. Start by increasing the signal to around 440hz. Check to see if your multi-meter reading went up from 0.30 to let’s say 0.32. If it does go up, then you need to continue increasing the frequency until you get the highest reading you can. If the multi-meter reading goes down, then decrease your signal to about 425Hz. Basically what you want to do is find out what frequency in Hertz will give you the greatest value reading on your multi-meter. That reading is then referred to as your peak value.

This diagram shows where you will connect your voltage meter to read the current.

Voltage Meter


1 ohm 25w

1 ohm 25w


Channel 1 of amp

1 ohm 25w

To Capacitor array.

1 ohm 25w

1 ohm 25w

1 ohm 25w


Channel 2 of amp

1 ohm 25w

1 ohm 25w

1 ohm 25w

1 ohm 25w

Keep playing with the frequency until you obtain the peak value on your multi-meter. The peak value is where the reading on your multi-meter is the biggest number. When it peaks, you know you have reached the optimum frequency for a 16uf capacitor. The goal here is to tune your frequency by increasing or decreasing from your starting point of 435Hz until you get the biggest number on your multi-meter.

Now what you need to do is take the frequency your signal generator was putting out when you got your peak value reading and enter that value into the calculator program found on this CD under dougproju.exe.

With any two of the three values, you can find the third value. With Hz and uf you can find mH. With mH and Hz, you can find uf. And with mH and uf you can find Hz.

Enter 16.000 in the capacitance box in the calculator section, followed by entering the frequency you were sending out when you got your greatest value on the multi-meter in the frequency box. After entering those two values, click on the inductance button and a value in mH will appear in the third box.

This value is your “real world” inductance of your coil.

Below is how the calculator in the dougproju.exe file will look if you happened to reach a peak when your frequency was at 443Hz.

Should this be the case, you would have entered 443 in the frequency box, followed by 16.000 in the capacitance box. Then when you clicked on the millihenries box, the calculator will have automatically calculated your coil’s inductance as 8.067015 as shown below.

In this scenario, the capacitance is a constant amount fixed at 16uf. As you played around with the frequency beginning at 435Hz, you found the frequency that created a peak on your multi-meter and entered that value in the frequency box. In the end, these two values calculated your coil’s inductance value in millihenries in the inductance box as shown here. Record your coil’s inductance for later use. From now on, you will enter your inductance in millihenries, then you will enter the frequency you want to run in the frequency box, and click on the capacitance box to see what capacitors to turn on to run that frequency.







There is an on line frequency/inductance/capacitance calculator you can use at the following web site:

The only difference is that you will need to enter inductance in henries. You will need to convert your millihenries calculation to henries. It is very simple to do. Simply move the decimal three places to the left. An example would be, 7.79 mH is the same as 0.00779 henries.

It takes 1000 millihenries to make up one henry.

The calculator that is referred to here can be found in the files section of the Yahoo group listed below, or if you are viewing this PowerPoint presentation on CD all you need to do is minimize or close this presentation and open the dougproju.exe file also on this CD.

From the web, go to dougproju.CAB and download this file to your desktop. Then un-zip it and save it on your hard drive. Use this icon to open the program.

All the other files support this one. When you click on calculator you will get three white boxes at the top of the page.

Enter coil inductance as millihenries (mH)
  • Enter capacitance as microfarads (uf)
  • Enter frequency as hertz (Hz)

Try this example to get the hang of using the calculator program. Enter 7.79 mH in the first box.

Enter 484 Hz in the third box.

Now click on “capacitance” under the second white box.

You should get a reading of,13.8807226903737

Your final result should look like this:







You will only need to use the capacitance value to two or three place values. (13.880)

Wavetek Meterman Test Tools 37XR 
  • Features:
    • Inductance to 40 H, frequency to 40 MHz, capacitance to 400 µF, logic to 20 MHz
    • Input warning tone when test leads are in wrong jack
    • 10,000 count, 0.1 % accuracy
    • 1000 V/750 V dc/ac True RMS
    • 10 Amps ac/dc, fully safety fused
    • Resistance to 40 MΩ
    • Continuity beeper
    • Min/Max, Average, Relative, Peak, and Data Hold
    • Auto power off to save battery life
    • Separate door for easy battery and fuse access
    • Magne-Grip™ Holster with magnetic hanging strap
    • CAT III 600 V, CAT II 1000 rated
    • UL (CULUS) listed
    • Three-year warranty
Technical SpecificationsL/C Ranges:2nF, 20nF, 200nF, 2µF, 20µF, 200µF, 2mH, 20mH, 200mH, 2HBasic Accuracy:L: ±1.5% (<0.5µF)±2.0% (>0.5µF)C: ±2.0% (<0.5µH)±5.0% (>0.5µH)Dimensions: 86mm x 180mm x 38mmBattery: Standard 9V

CSI6243 Digital Capacitance and Inductance Tester

  • The CSI6243 Digital Capacitance and Inductance Tester features a large 3.5 digit LCD display and 10 total ranges (6 ranges for capacitors and 4 ranges for inductors). Also supplied with OSHA yellow rubber holster and safety design test leads. Highly accurate with Auto-Zero adjust and overload indication. A very handy piece of test equipment for general trouble shooting and component testing. Features
    • 3-1/2 digit, 21mm LCD with a max reading of 1999
    • 6 capacitor ranges/up to 200µF
    • 4 inductive ranges/up to 2H
    • Auto zero-adjustment, high accuracy
    • Overload indication feature
The next hole I cut was for my frequency generator. You have two choices here. You can either purchase a bench model frequency/signal generator or use a free computer program.

If you want to use your PC, there are several programs available on the Internet. One good frequency generator program is called the fg_lite. You can download it free from the following site, or simply minimize this presentation and open the fg_lite.exe file found on this CD:

I chose to purchase a bench model signal generator so I could have my entire device in one place, and so I wouldn’t have to use it near my desk top computer which is in another bedroom. I do not have a laptop. I ended up purchasing a cheap off brand frequency generator on eBay.

If you want a bench model frequency generator and cost is not an issue, the Ramsey SG 550 is said to be pretty good. It is more expensive than using your PC, but it is one of the cheapest bench models I have found. You can purchase a Ramsey SG550 from the following web-site.

This unit can be purchased pre-assembled or as a do-it-yourself kit.

Ramsey SG 550Frequency Generator

Once you have decided on what type of equipment to purchase, you will need to purchase your capacitors. For capacitors, I used Allied Electronics. Their web site is:

The following page has the list of capacitors and their corresponding part numbers should you decide to purchase them from Allied Electronics.

Capacitor array inside my cabinet. Notice the shelf where the top level of capacitors rest. This keeps them from touching each other.

You are going to have about 16 switches when you are done. As you saw my machine has 20. That’s so I can add more later if I need to. But you only need 16 to start with.

I chose to write the exact capacitance above my switches. You can designate your switches with letters like, A, B, C, etc. if you wish. You just need some way to designate which switches you need to flip for each frequency you use.

For this illustration, I will use A, B, C, etc. Then I will give you the exact capacitance value each switch will have. The information in the parenthesis is what it takes to make the exact capacitance shown after each example.

The reason for this is that you cannot purchase some capacitors in the range you need, so, you have to build them yourself. This is done by connecting two or more capacitors together in either series or parallel, and sometimes both ways to get the exact capacitance value you want.

More on capacitors in series and parallel later. The (uf) after the number stands for microfarads. A microfarad is the unit measurement or value of a capacitor.

A – No capacitor used on switch one.

B – 30uf (1 30uf part #225-5010)

C –16uf* (2-8uf in parallel #591-7045)

D – 8uf* (1-8uf part #591-7045)

E – 4uf* (1-4uf part #591-7025)

F – 2uf (2-4uf in series part #591-4205)

G – 1uf (3-3uf in series part #591-4200)

H – 0.5uf (2-1uf in series part #591-6085)

I – 0.25uf (2-0.47uf in series part #591-6075 with 1-0.015uf in parallel part #591-6150)

Capacitor values with an * next to them are a newer design than what is illustrated on the dougproju.exe file. The pictures in the dougproju file will not match the capacitors listed here. These new ones are a can design with clips on top to connect to.

J – 0.122uf (1-0.1uf in parallel part # 591-6175 with 1-0.022uf part #591-6155)

K – 0.062uf (1-0.047uf in parallel part #591-6165 with 1-0.015uf part #591-6150)

L – 0.033uf (1-0.033uf part #591-6160)

M – 0.015uf (1-0.015uf part #591-6150)

N – 0.01uf (1-0.01uf part #591-6145)

O – 0.0075uf (2-0.015uf in series part #591-6150)

P – 0.005uf (2-0.01uf in series part


Total Allied Electronics Parts List

1 - #225-5010

3 - #591-7045

1 - #591-7025

2 – #591-4205

3 - #591-4200

2 - #591-6085

2 - #591-6075

1 - #591-6175

1 - #591-6165

1 - #591-6160

1 - #591-6155

5 - #591-6150

3 - #591-6145

26 Total capacitors needed to make your capacitor array.

Below is a diagram for the new 16uf capacitor configuration. For the 8uf and 4uf capacitors simply connect one terminal to the switch and the other terminal to the terminal wire leading to the coil.

AC can capacitors wired in parallel below. AC capacitors are non-polarized and don't have + and - markings.

+ and – terminals shown for illustration purposes only.

16uf Capacitor Configuration

From switch

Negative terminals

To terminal wire and on to coil.



Positive terminals

Top of cans

To Coil

From switch

How to hook up the

4uf, 8uf, & 30uf can capacitors.

4uf, 8uf, & 30uf can capacitors

From switch

To terminal wire and on to coil.

AC capacitors are non-polarized and don't have + and - markings.

+ and – terminals shown for illustration purposes only.

Top of can

Soldering Tips

Soldering is not difficult to learn. Keep these points in mindDirty corroded leads and terminals won’t allow the solder to flow and stick. Since you are ordering new parts, this should not be a problem, but if any leads, terminals or wires look tarnished, rub them with a little steel wool or fine sandpaper etc. until clean.Make good physical connections before soldering. Simply laying one wire against another and soldering them is inadequate. Wrap wires and squeeze tight with pliers for heavier ones.The soldering iron must be hot enough to heat the joint you are working on- preferably pretty rapidly. A small “pencil” iron may not be hot enough for heavy wire or thick joints. A soldering “station” or “gun” type of iron should be plenty adequate. Soldering "gun" type irons are relatively cheap and handy for the homeowner/hobbyist.On a new iron, melt a little solder onto the hot new tip and wipe with a wet piece of sponge until it appears covered in solder and shiny. Use this sponge to wipe the tip clean frequently during soldering, preferably between soldering each joint.

Heat the joint and melt the solder into the hot joint with the iron still in place. Don’t melt the solder onto the iron. Melt it onto the joint.Don’t move the joint as it is solidifying. As soon as it’s solid, you can wiggle test it. With good modern rosin core solder, it should cool to be shiny looking. If it is dull gray or grainy looking, it probably was moved while cooling. Just re-melt it and cool without moving.Use 60/40 Rosin Core solder. Fine gauge solder is easier to use than thick solder, but either is ok. Rosin Core solder is non corrosive and the rosin serves as a flux so no other flux is needed.Don’t over heat the components that you are soldering. Heat the joint just long enough to melt the solder easily, completely, and rapidly- then get out. A sensible precaution is to clip an alligator clip or other heat sink to the lead of the component to draw the heat away, but this is not necessary on the capacitor array if only the necessary heat and time are used and no more. Extra caution should be used when the capacitor leads are very short, as when soldering two capacitors together in series.
Learn to see when the solder is flowed well. When the joint is hot enough, the solder will spread rapidly and flatten out. As soon as this happens and there is enough solder in the joint, pull out and let it cool for 5 seconds or so. Use just enough solder to cover the area and fill the gaps in slightly. Any more will just ball up and, if enough is added, drop off.Solder in a well ventilated area, preferably with a fan, and wash your hands when done since the solder contains lead. Gently wiggle check your joint when done. If the joint moves or is dull appearing, simply re-solder.

You will not need to solder all of your capacitors since several of them are can capacitors. For the can capacitors however, you will need slip on clips to connect to the capacitor leads. You can purchase crimp on clips. This is what I purchased, but I also soldered the connections for extra safety. I did not want any leads coming off from the capacitors.

The next slide will show how to solder one of the special capacitors where you first solder two capacitors in series and then in parallel with another capacitor.

The 0.25uf capacitor is a little tricky because you first have to solder two 0.47uf capacitors in series or end to end and then connect another 0.015uf in parallel or side by side with the one you just soldered. Because of the short leads coming out of the capacitors, it will end up looking like a triangle.




This will give you a capacitor with a capacitance value of 0.25uf.


When it comes to the switches needed to turn on or off your different capacitors, you will need to decide what you want to do. You basically have two choices. Household switches like you have in your home or toggle switches like I used on my device.

I went with the toggle switches mostly because I wanted a clean looking device. The household switches which are one third to one fourth the price of a toggle switch simply need 12 gauge solid wire pushed into their holes to wire them up.

The next three slides show pictures of capacitor arrays built in boxes. The first box shows toggle switches. The two following that use household switches. Notice how the black wires jump from switch to switch.

Here is a front view of the capacitor toggle switches. The last two on the bottom right are for future capacitors should the need arise. Each switch is marked with its capacitance value such as 0.122uf.
Capacitor array using household switches, back view.

Hot wire from amp must connect to one side of every switch. (1)

30uf Can capacitor

After connecting hot wire from amp to one lead of each switch, See (1) Connect capacitors to the other lead of each switch.

Terminal wire which goes to coil.

You need one switch with no capacitor.

Empty switches for future capacitors.

Capacitors complete the circuit sending the current on to the coil.

Back side of a capacitor array with the new updated can type capacitors.

The 30uf capacitor is the same as the old design.

The new can type capacitors

These 4uf, 8uf, and 16uf can type capacitors took the place of the other polypropylene GE capacitors seen in the previous picture.

Each capacitor switch is, in effect, allowing you to engage each different capacitor to get the desired capacitance value required for the frequency you want to run.

For instance, if you want to run the frequency 612 Hz, you will need a total capacitance of 8.68uf for a coil with an inductance of 7.79 mH. One of my coils measures 7.79 mH which is why I use it as an example.

When you put two capacitors side by side which is known as parallel, you simply add up each capacitor’s value and the total is what the amp sees. To get the 8.68uf capacitance you simply flip on the following switches: 8uf; 0.5uf; 0.122uf; and 0.062uf. The sum of all these capacitor values is 8.684uf.

To see exactly how to solder all of these capacitors together, the best resource is the dougproju.exe file on this CD or on the web in the files section at:

Go to the files section and click on dougproju.CAB

This file is huge, 3510 KB. It will take quite a while to download. I recommend you save it to your desktop, then un-zip it and save it on your hard drive. When you try to open it, click on the file that looks like this.

The rest of the files in the dougproju.CAB file are all attachments that support the dougproju.exe file. When you pull it up, click on the capacitor box. You will get a set of capacitor values. Click on each value such as .25uf, and a picture will open up along with a detailed description of how to solder those specific capacitors to get the capacitance value you want.

After you finish that capacitor, simply click again on the open picture and it will close. There is a verbal description along with a picture so you can see how the engineer soldered the capacitors. It’s an excellent tool.

The next thing you will need to solder are your resistors. For this you will need ten 1 ohm 25 watt wirewound resistors. You can purchase these from Source Research Inc. at:

Order part #25W1D0

You will solder five resistors in parallel or side by side for each channel of your amp.

Here is how I soldered my resistors. As you can see, I have two sets of five resistors soldered in parallel. Each set of five resistors has a value of 0.2 ohms.

You will connect one set to channel 1 and the other set to channel 2. They will then come together before going on to the capacitors.

Connection point of both sets of resistors.

The resistors shown here are soldered side by side. This is correct; however, it is better to have some air space between each resistor which I do not have. They are air cooled and when soldered so close together, they can get hot.

Ideally, there should be air space between each resistor.

Detailed list of how to solder resistors.


Air space between resistors to keep them cool.

1 ohm 25w

1 ohm 25w


Channel 1 of amp

1 ohm 25w

To Capacitor array.

1 ohm 25w

1 ohm 25w

1 ohm 25w


Channel 2 of amp

1 ohm 25w

1 ohm 25w

Order 10 resistors,

Part #25W1DO from:

1 ohm 25w

1 ohm 25w

This diagram shows where you will connect your voltage meter to read the current.

Voltage Meter


1 ohm 25w

1 ohm 25w


Channel 1 of amp

1 ohm 25w

To Capacitor array.

1 ohm 25w

1 ohm 25w

1 ohm 25w

1 ohm 25w


Channel 2 of amp

1 ohm 25w

1 ohm 25w

Order 10 resistors,

Part #25W1DO from:

1 ohm 25w

From Resistors

The hot wire from the resistors must go to every switch. The circuit will be completed when a switch is turned on and current flows through that capacitor and on to the coil via the terminal wire.




4 uf etc.

Terminal wire

To Coil

Making a coil

When you make your coil, you will need a 500 foot spool of 12 gauge solid copper wire. You may want to make several coils eventually, but you should start with one in the 7 to 8.5 mH range.

Once you know what your coil’s inductance is (value in millihenries abbreviated as mH) you can use the calculator mentioned earlier to find out what capacitance you will need to run a specific frequency.

To make one of my coils (which is a 7.79 mH coil) I purchased a large can of coffee. I chose this because it measured exactly 6” in diameter. After ten years of experimentation by the designer of the coil device, it was determined that a six inch diameter coil simply worked the best.

The dimensions given to me to make my coil were to wrap the wire around a 6 inch object, 2½ inches wide, and 1½ inches thick. In doing this I got a coil that measured 7.79 mH.

The inductance of your coil will be a combination of length of wire you use, how tight you wind it, the diameter of the object you wind it around, and how thick you wind it.

Six inch inside diameter coil.


Once the coil is made, you will need to attach a 15 foot 12 gauge speaker wire lead that will connect one end of the coil to the output of the capacitor array, and the other end to one of the negative sides of the amp’s output terminal. This coil does not have a 15 foot lead connected yet.

The two coils in the lower right corner have mH values of 5.82 and 11.2 mH.

Wire nuts connecting speaker wire to coil.

12 gauge speaker wire.

5.82 mH

11.2 mH

Another option to making a coil is to use a flower pot to wrap your wire on. Others have used this method and say it’s easier to get the coil off after making it. They also wax the flower pot before starting to make the coil.

You will want to use some electrical tape or plastic wire ties to keep the wire together. The tighter you can wind the wire, the more inductance you will get out of a smaller amount of wire.

If you are interested, here is the contraption I used to make my 6 inch coil.

I used two by fours to make a simple box that I mounted my coffee can between. I used 3 inch screws so I could assemble it and disassemble it easily.

Plastic 5 gallon paint can lids used to keep wire in the 2 ½ inch boundary.

Coffee can

¼ inch x 20 threaded rod purchased from automotive store.

Cardboard wrapped on can to make it easier to take wire off can after winding.

To keep the coil from coming apart when I disassembled it, I hot glued the wire every time I put a new layer of wire across the coil. After removing the coil from the coffee can, I put tape and wire ties on it.

6 inch ¼ x 20 carriage bolts used to hold the paint can lids in place.

Winding the coil

To hold the wire as I wound it on the coffee can, I used a piece of ¼ inch plywood and two pieces of two by four and a ¼ x 20 threaded rod. I bent one end over and put a nut with washer on the other end to hold it together.

Before putting the can into the two by four box, I attached a metal paint can lid from a one gallon paint can to make the plastic lid have more rigidity.

Connectors – Banana jacks make the safest and easiest connectors.

Banana Jacks from Radio Shack

7.79 mH Brooks coil

15 foot long 12 gauge speaker wire.

When you get ready to run the machine, the first thing you will need to do is pick a frequency. Frequencies can be obtained from the Lyme-and-rife or QSC1850HD Yahoo groups. You can also use the CAFL list.

You will find the CAFL list on this site:

Once you have decided on the frequency you want to run, go to the calculator section of the dougproju.CAB file mentioned earlier and calculate the required capacitance value in microfarads (uf) for that frequency.

Now flip the capacitor switches that will give you the closest value as calculated. Make sure your amplitude (volume) is turned all the way down. You do not want to flip switches with the voltage at a high level.

Turn both channel 1 and channel 2 gain knobs to maximum. Amber light should come on. If red light comes on, something is wrong.

With the frequency generator putting out a signal, begin to turn up the amplitude (volume) until you read 1.5 volts on your multimeter. 1.5 volts actually means you are putting out 15 amps. Leave this on for the desired time and then turn down the amplitude as far as you can to start a new frequency.

Schematic of a QSC 1850HD




Signal Generator

CH 1

Cooling fan Back of amp


CH 2

1 clip limiter OFF 2 30 Hz filter OFF 3 filter OFF 4 parallel input ON 5 parallel input ON 6 bridge mono OFF 7 bridge mono OFF 8 filter OFF 9 30Hz filter OFF 10 clip limiter OFF

Mode Switches

Voltage Meter

Five 1 ohm 25watt wirewound resistors in parallel

Five 1 ohm 25watt wirewound resistors in parallel

Capacitor Array in Box


For details on how to make the capacitor array, go to dougproju.CAB file in the file section of the Yahoo group:

This brings us to the end of this presentation. It is my hope that you will now be able to proceed with the building of your own QSC1850HD coil device.

If you have any additional questions while building a device of your own, please feel free to post your questions on the following web-site.

It is the goal of this group to help as many people as possible with the construction of their own QSC1850HD coil devices.

To obtain additional CD’s of this PowerPoint presentation, send your request to [email protected]

May God Bless