Simplex Mic Pre


The Simplex is a high quality tube microphone and instrument preamp with pure and transparent dual gain stage class A subminiature Micro Tube design
featuring Input and Output transformers handwound by Jensen.

Providing a natural sound experience with a spacious, warm, sweet and detailed sound stage
delivered by the lively responsive and wide frequency range of the Micro Tubes.

A microphone preamp is arguably the most important sound generating device in any recording setup.
It comes right after the weak signal from a microphone or instrument pickup and boosts it to recording line level.
Without a fine quality preamp, music and sound quality is lost right in the beginning of a recording signal chain
and even excellent effects and mixing consoles can't recover and infuse the sound with it's original pure quality.
The Micro Tubes in the Simplex enhance that quality with their unique, lively and musical character.

Micro Tubes (subminiature) - Small size, but sizable warmth, presence, power and transparency.
These special purpose tubes were developed by the military to operate smoothly under extreme conditions with maximum life span.

Dual gain stage class A subminiature NOS tubes

Custom Mercury Magnetics humbucking power transformer

Super-quiet power and dc-filament supply

Jensen nickel-core transformer

Variable microphone input impedance

XLR gold pin connectors

Metal film precision resistors

Hermetically sealed mil-spec paper/oil caps
Precision gain potentiometer

Carling heavy-duty switches

Fast and no-loss lighted VU meter

Read the Simplex Manual



Rear Connectors:

Rear Control:

Front Connector:

Front Controls:

Voltage Gain (continuous):

Input Impedance:

Output Impedance:

Maximum Output Level:

Frequency Response:

VU Meter calibration:


Dual gain stage class A subminiature tube Pentode and Cascode

Microphone Input XLR Transformer Balanced
Output XLR and TRS Transformer Balanced (TS Unbalanced)

Ground Lift switch for Pin 1

Instrument Input 1/4" Unbalanced

Power On/Off
48V Phantom Power On/Off switch with LED
-20dB/0dB Pad switch
+/- Polarity switch

Input Control for Impedance and Sensitivity
Gain Level Control
Output Control for Headroom

Microphone 70 dB
Instrument 50 dB

Microphone: Variable sweep 0 to 10K Ω
Ribbon Mic: Variable sweep 10K to 30K Ω
Instrument: 500K Ω

600 Ω

+18 dBu

20 Hz to 20 kHz

+4 dBu/1.228 Vac at 0 dB/100%

Handmade in USA

100/120/220/240VAC (50/60Hz)

Level and Phase Reference

Input transformer data

Output transformer data

There are several sound clips across the Amplifier and Tone Tubby pages made with the Simplex.

Studio tracks sound samples coming soon ...