MOPA Amplifier Historical Tube Powered 1930’s Style Plasma Tube Power Amplifier Now Boosted to 162 Watts!

Now boosted to 118 Watts of RF Output! Here’s a video showing how I use the MOPA Oscillator/Amplifier along with the GB4000 Frequency Generator. I also explain why I feel strongly that this is the most important device out there. Let me know if this opens up any new questions for you.

thanks for watching!

MOPA 1930’s Replica Vacuum Tube Driven Oscillator Amplifier

Download MOPA Amplifier Oscillator GB4000 Brochure PDF

The M.O.P.A. Amplifier (Master Oscillator Power Amplifier) provides a variable 2.2 MHz to 3.8 MHz frequency oscillation with low frequency pulsation from the GB4000 function generator. Is is a 1930-1950 M.O.P.A. replica. When connected to the GB4000 it is capable of outputting 8 frequencies simultaneously.


MOPA 1930’s Replica Vintage Vacuum Tube Oscillator / Amplifier tech specs:

  • Built by hand in the USA with each unit individually tested for quality assurance with 1 year warranty.
  • Proven Design: Vacuum Tube technology used for over 80 years combined with solid state technology for reliability while retaining the output style delivered only by vacuum tube oscillators.
  • Amplification Method: Original Vintage Vacuum Tube Amplification
  • Amplification Voltage: High Voltage. Unique vintage design uses a high 1400 volts to drive the vacuum tube oscillator retaining the authentic 1930’s type of output.
  • Amplification Current: Low Current. This design takes advantage of the high voltage amplification and uses only 30 to 180 milliamps of current.

Modern systems lack the vacuum tube oscillator (which is at the heart of the MOPA Oscillator). The big difference that you should understand is that these modern designs use high current and low voltage. The Vintage MOPA Oscillator design instead uses the 1930’s technology to achieve a better output with high voltage and low current! This is primary difference between the vintage vacuum tube technology and the more modern solid state amplification method.

Here’s a few more specs on our new 1930’s replica MOPA Oscillator / Amplifier:

  • It’s got a built in Milli-amp power meter so you know what power output you are running.
  • The waveform is sine wave just like the 1930’s vintage oscillators.
  • The sine wave is an analog wave due to the vacuum tube oscillator so it doesn’t need a Digital to Analog converter like all the solid state designs require to simulate an analog waveform.
  • The carrier frequency is variable and adjustable using the knob on the front of the unit. Because of the 1930’s vintage replica design this knob actually controls a variable capacitor which is controlling the frequency of the carrier wave.
  • Carrier frequency range is approximately from 2.2 MHz to 3.8 MHz (2,200,000 cycles per second to 3,800,000 cycles per second).
  • Power output is variable with an average power output of 115 watts (at 140 milli-amps showing on the meter).
  • Peak power output is much higher when gated/modulated with the output from the GB4000 function generator. The peak output power is 162 watts with a sharp leading edge of the 1400 Volt spiked waveform generated from this type of output.

Remember that modern solid state equipment uses lower voltage and high current output, but the M.O.P.A. is a high voltage low current output. This is the same method used in the 1930-1950 equipment.

The M.O.P.A. Amplifier/Oscillator is capable of the following:

  • Can output frequencies through a metal or plasma tube antenna (not sold by us but we know some good suppliers).
  • The maximum frequency output available with capability to run 8 frequencies at the same time with the GB4000.
  • Amplifier output is analog using the original vacuum tube amplification.
  • Allows input of GB4000 audio frequencies up to 40,000 hertz with 100% AM modulation just like the 1930’s vintage oscillators
  • Gating or pulsing of frequencies from 1 Hz to 40,000 Hz is possible with the GB4000 connected.
  • Allows any frequency from 2.2 MHz to 3.8 MHz to be used as a stand alone frequency or as a carrier wave for square wave audio frequencies input from the GB-4000.
  • Any frequency from 2.2 MHz to 3.8 MHz can be gated or pulsed using the GB-4000.
  • Connects to the GB-4000 through regular banana jacks or a BNC connection.

Here’s a few advantages of this 1930’s Vintage MOPA Design over the modern simulations:

  • Quick and easy, instant ignition of a plasma tube (not sold by us). No SWR meter needed. If you don’t know what one is trust me you don’t want to! And with our MOPA design you won’t need to.
  • The broadcast range is up to 1700 feet with a useful range of about 30 feet when using a plasma tube. I personally use it in a range of 1 to 5 feet and find this to be best with a plasma tube.
  • Compact design with a small footprint of only 10.5″ wide x 17″ long and 10″ high.
  • The power usage is only 150 watts.
  • Only weighs 19 pounds!

Note: This unit runs on 110-120 Volts but if you have 220-240 volt power we can build one for you for that power – it just takes a few extra days.

Why should you purchase the GB-4000 and M.O.P.A?When the GB-4000 is combined with the M.O.P.A. the ability to run from one to eight frequencies up to 40,000 hertz through a gas tube is possible. No other instrument has this capability.

The M.O.P.A. is the only gas tube instrument with the ability to use a variable RF frequency from about 2.2 to 3.8 MHz as a carrier frequency or as a stand-alone frequency.

We use the superior high voltage low current design over the low voltage high current design.

We can usually ship within 24 to 48 hours after receiving your purchase agreement.

Both the GB-4000 and M.O.P.A. come with a one year parts and labor warranty.

We not only give superior support but give technical support by phone for as long as you own your instrument.

GB4000 with MOPA Amplifier / Oscillator


*Any plasma tube instruments that are EM (electro-magnetic) do not use RF (radio frequency) frequencies or an RF carrier frequency. They use coils to produce a high electromagnetic field to carry the frequencies to the target. They are limited to about 10,000 hertz but a few go to 30,000 hertz. Due to the fact that many manufacturers use similar designs and use an EM field to deliver the frequencies, we have included them in the chart as “EM devices with Plasma tubes.” Since they do not use an RF carrier frequency it is
almost impossible to determine their power output. Almost none of these maufacturers list the power output of their equipment. For this reason we list in the “Power level” field No RF so that the reader knows that they do not us an RF carrier frequency or output any RF frequencies. They will have names such as Light Wave Blaster, EMEM, Beam Ray, Plasma Plus II, F-117, EMEM2, EMEM3D, EMEM3DV, EMEM5’s EM7V and System 8CE EM+. They generally are very good instruments and work well. The only limits, except for the EMX, are the frequency range. They only output low audio frequencies. The EMX goes up to 20 million hertz but only has the power output of one tenth of one watt. All the original 1920s through the 1950s instruments used RF and had an average power output from 25 to about 50 watts.

Connecting the MOPA Vacuum Tube Amplifier / Oscillator to a plasma tube antenna:

There are many options for plasma tubes and we’ve even arranged one that has a very reasonable price for a basic tube that is optimized for the power output from the MOPA. We’ll provide their contact information prior to shipping your MOPA.

Shown below is the MOPA connected to a plasma tube. This type of tube, which has no internal electrodes that cause early burnout, is the best to use for reliability and affordability:


And here it is with the tube glowing while the GB4000 is running frequencies into the MOPA:

The way to connect the GB4000 to the MOPA Vacuum Tube Oscillator / Amplifier is with a BNC connection (GB4000 will need to be sent to the factory for modification if yours doesn’t have one – If you’ve had your GB40oo for more than a year it will likely need to be sent in to be modified) as shown below:


Now the MOPA comes with a built in Frequency Counter to make it really easy to properly read the frequency output of the MOPA Frequency Amplifier.

Since the M.O.P.A. Oscillator/Amplifier uses an old style variable capacitor it is necessary to have a frequency counter so you can set the instrument to what ever frequency you wish to use from 2.2 MHz to 3.8 MHz.

M.O.P.A. Vacuum Tube Amplifier / Vacuum Tube Oscillator with 162 watts Peak RF Output


Update: Now we are shipping the MOPA units much quicker so there’s no need to break up the order into two payments. There is still a purchase agreement which must be signed which is very simple and acknowledges that we are not responsible for any interference that may be a result of using the MOPA.

If you have questions about the replica M.O.P.A. Vacuum Tube Amplifier / Oscillator

Important Note: All units are built to order and you must sign an agreement which waives our liability for any potential FCC or AM radio interference issues. Once you receive your unit you’ll have 30 days decide if it’s right for you. You may return it for refund during this period and IF (and only if) you keep it in perfect, new condition without any scratches or other damage we’ll waive the standard $300 restocking fee, but you must return it to us at Future Tech Today Inc. You will have to cover the shipping that we paid and your return shipping, but that is only fair.

All Units will include the following:

  • DVD setup video
  • 1 year parts and labor limited warranty
  • Information on a good source for a tube as well as a secondary source
  • Built in Frequency Counter

Tube not included.

Note about plasma tubes: I’ve coordinated with a supplier of a nice, simple helium/argon filled tube which is optimized for the power output of this vintage MOPA design and they charge $335 plus shipping for it. It’s a 2″ diameter, 14″ long tube made of pyrex glass with no internal electrodes because these have impurities in the metal which causes the tubes to burn out faster (especially with the high peak power output of the MOPA design!). I’ll provide you with the contact information at least a week before your unit is ready to ship so you can get one on order if you choose. There are plenty of suppliers of plasma tubes although they typically cost much more than this and most of them will burn out with the power delivered by the vintage MOPA design. With this $335 tube I can guarantee it will handle the power output of the MOPA.

Start your order online here:

  • Choose whether you are ordering “MOPA Oscillator/Amplifier Only” (if you already have a GB4000) or the “MOPA Oscillator & GB4000 Generator Combo”
  • Investment for MOPA Oscillator is a total of (no tube included): $2,495
  • In 1 to 3 days your unit will be completed and ready to ship. Shipping is included for US orders only.

MOPA Oscillator & GB4000 Generator Combo:

  • If you don’t already have a GB4000 you’ll want one so your total will be $4,220 (tube not included). If you are in the US you can use this button which adds the GB4000 Generator ($1,725) to the MOPA Amplifier/Oscillator ($2,495) – the MOPA now has a frequency counter built in so the Elenco Frequency Counter is no longer needed.

  • In 1 to 3 days your unit will be completed and we will ship your unit. We cover the shipping in the US. If you are outside the US we will contact you after you place your order to discuss shipping options.

Add to Cart

MOPA Oscillator/Amplifier Only:

  • If you already have a GB4000 this button is the one to use to order your MOPA: $2,495 including US shipping. If you’ve had your GB4000 for over a year you’ll need to send it in for a modification but if you’ve purchased it more recently you’ll be good to go. We will contact you with information on where to send your GB4000 for the factory authorized modification if your GB4000 doesn’t have a BNC jack on the back (recent ones do). There is no cost for this modification aside from shipping.
  • In 1 to 3 days your unit will be completed and once your final payment has been received we will ship your unit. We cover the shipping in the US and if you are in Canada or Overseas we’ll get you a quote for shipping.

    Add to Cart


Will we be shipping your MOPA Vacuum Tube Amplfier & GB4000 Combo to a US Address?


*Yes for US Address
*No for International Address

Will we be shipping your MOPA Oscillator/Amplifier Only to a US Address?


*Yes for US Address
*No for International Address