Hybrid tube preamplifier 

The main concept of the hybrid microphone preamp was a combination of two circuit topologies – tube and transistor. The hybrid solution solved a number of technical problems, simplifying circuitry, bypassing the heap of passive elements in the sound path, which are inherent in tube equipment.

The hybrid solution made it possible to create a device with a high bandwidth => 100kHz, signal gain levels of 60 dB, and record low distortion of 0.00095% THD! The electro-vacuum tube is the core of sound amplification, with high parameters, thanks to our know-how in circuitry.
In fact, we get a device that surpasses the popular transistor preamps in terms of noise and signal distortion, but is a 100% tube device!


The goal of creating a preamp with the widest possible throughput and a large gain and without distortion was due to the Vacuum preamp being able to enable sound engineers to get the tone of the instrument and its character, which can be called MixReady. Since our device does not cut the spectrum of the signal, and we have a large bandwidth across the entire spectrum from 10 to => 100 kHz, leaving the accuracy of the sound source displayed in front of the microphone, and the amplification is able to catch the smallest details of the room reverb, and those spectral components below -60dB without intermodulation distortion, thereby we get better detail with minimal distortion.

Another factor that distinguishes our device from others is the use of electricity sources to supply phantom power, without using a resistive circuit, which usually tends to damp the signal between a hot and a cold signal. In our case, we have a complete separation of “hot” and “cold signals” without interacting with each other.
In our power supply implementation, the preamp has two stabilizations – in the main power supply unit and on the amplification boards. This may seem complicated, but the thoughtfulness of this detail made it possible to have a completely distributed and independent from each other system of “current circulation” and the absence of the influence of channels on each other.


Since the analysis of our personal experience is an integral part of the instrument creation process, we are free to implement certain aspects as we would like to see it in any other device. So, for example, the output attenuation knob has a discrete potentiometer, which makes it possible to precisely align this parameter without an error in the balanced output signal, thereby receiving even smaller distortions. Since simple potentiometers have an error of up to 20% of a given value, our choice was in favor of discrete potentiometers.

We can set the lamp current and the middle point of the output voltage precisely. This makes the device compatible with any 12ax7, 12at7 lamps and the only difference that will be noticeable is the gain coefficient, since each type of lamp has its own. All this leads to a minimalistic solution, without piling up all kinds of adjustable settings.

The two main controls are Gain, Volume, phase inversion, and phantom power.

SW Vacuum 160mv gain 65dB

Mentioning universality, it is worth answering a couple of simple questions.

  • Is this preamp designed to work with other “Simpleway” devices?

Yes! This device unleashes the full potential of your sound and takes it to a whole new level, in conjunction with our diboxes and microphones. It is worthwhile to understand that it was them we primarily used to debug the Vacuum preamp. And it complements our duet with a third warrior on the side of a clean and dynamic sound.

  • Can this device be used with devices from other manufacturers?

Yes, if you want to hear how they can sound, then our preamp will help them open up.

The patent-pending preamp circuitry makes it extremely stable with the power sources it is connected to, as well as tube for replacement choice, thereby making the device usage simple and less problematic. There is no need to search and select correctly matched tubes of certain manufacturers. Preamp effectively transforms the magic of tubes, no matter what they are.

Since the tubes use high voltage, we DO NOT recommend trying to replace anything yourselves, as it can not only harm the device, but also is life-threatening. In such cases, you always can contact our team, which is ready to help, suggest and support in matters of any complexity.

New Gear Day!
Straight from the box the unit impresses with its smart looks and solid construction. Everyone who heard this excellent Simple Way product was impressed with it. It does exactly what you want a mic-pre to do. Vacuum is one of a small number of pre amps that has been designed from the ground up, making no claims to emulate equipment from the past. The quality of sound is excellent. Highly recommended!
Peter Glushkov, I owe you big time!


  • Input Tubes: 12AX7 dual triodes, low noise and stable bias
  • Output type: Transistor
  • I/O: Through Balanced Scheme
  • Microphone preamplifier: Selectable 48V phantom power (current source and phase reverse)
  • Gain: 60dB max Microphone preamplifier.
  • Input Impedance: 200 kOhms
  • Frequency Response: 20Hz to 120KHz @ 50dB(gain)
  • Maximum Output: +35 dBu (into 1Kohm load)
  • THD: <.0008% @ 1KHz
  • Dynamic Range: 120dB typical
  • Output Impedance: =>30 ohms
  • Power Consumption: 0.240 Amps (240 milliamps = 240mA) @ 240V = 57.6 Watts
  • Mains Voltage Frequency: 220volt/50hz