The MP566 is a dual-triode vacuum tube circuit preamplifier based on a design that has been used in several famous devices from the 50's, which has been adapted to the '500' format of API*.

With its fully powered triodes and its two transformers, the MP566 brings the most fulfilling warmth and color to your Lunchbox.

Highlights

• Dual triode design,
• Input and output transformers,
• High 68dB gain will please the most demanding ribbon mics,
• Variable input and output levels for total control over tube saturation,
• 2 different negative feedback levels (Mid/High Gain) for sweet or more aggressive sound,
• Input pad (Low Gain) for hot mics or line levels,
• Full 225 Volts tube supply and full 150mA tube heater,
• 1/4" DI jack, high impedance input for instruments,
• Sequenced power-up to limit the total inrush current,
• Total current draw less than 160 mA,
• Available assembled or as a full kit (everything included).

Controls

1: IN This potentiometer sets the microphone drive level before the tube stage,

2: Clip LED Green when a signal is present, turns red when getting close to saturation,

3: OUT This potentiometer sets the output signal level. In combination with the IN knob, it allows you to control the amount of tube saturation you want,

4: GAIN 3 position switch

• LOW : Inserts a -20dB pad before the input transformer. Allows you to manage loud microphone signals or line level signals,
• MID : Sets 27dB of negative feedback around the tube stage producing a clean and sweet tone,
• HIGH : Reduces the negative feedback to only 7dB which increases the gain by 20dB and produces a faster, more aggressive tone,

5: POL Reverses the polarity (phase) of the output signal when on REV. In the center position it is a Mute

6: 48V Activate the phantom power for static microphones,

7: DI High impedance direct instrument input, connected to the first triode grid.

What's in the kit?

Absolutely everything!

• Passive components (resistors, capacitors, inductors),
• 2 transformers
• Active components (tube, diodes, transistors, LED's, IC's),
• Front panel elements (switches, potentiometers, knobs),
• Connectors, relay,
• PCB's,
• Front panel and side panel,
• All hardware

You bring the solder (use good quality solder, 1mm diameter max) and the Lunchbox.

Difficulty level

The kit difficulty level is average. Nothing difficult but because of the high voltage needed by the tube, it is not recommended to beginners. Good soldering practice is required.

There is no setup. A digital multimeter is needed to test the various voltages.