MP-AB528 Microphone preamplifier

The AB528 is a transformers coupled, class A mic preamp. The design, from the late 60's, is inspired by a legendary console, that was used at the most famous London studio by the greatest artists, such as the Beatles or Pink Floyd.

The AB528 is a pre with character, vintage sounding, warm and silky, with a lot of attitude when driven hard.

Highlights
Transformers on input and output,
0 to 60 dB of gain, 66dB on 300 Ohms
Switchable between 300 Ohms, 1200 Ohms and line input impedance,
DI input, relay switched, the signal passes through both transformers,
Signal/Clip LED,
All low level signals switched by relays,
High grade components throughout,
High grade double sided PCB with plated holes,
Easy build,
Available assembled or as a full kit (everything included).

Controls
1 Output level: Potentiometer that sets the signal level to the output stage. Works like a console fader and allows driving the preamp hard.

2 Signal/Clip LED: Flashes green when a signal is present and turns red 3 dB before clipping

3 Gain switch: Sets the gain between +10 and +60dB.

4 Input impedance: Center is the standard 1200 Ohms input impedance. Left sets a 300 Ohms low impedance and adds 6 dB of gain, useful for ribbon mics. Right sets a 6 kOhm impedance input pad for line levels.

5 Polarity; Sets the polarity (phase) of the output signal

6 Sends phantom power to the microphone

7 High impedance input (1.5 megohm) for instruments. The instrument signal goes through both transformers.

What's in the kit?
Absolutely everything!

Passive components (resistors, capacitors),
2 transformers
Active components (diodes, transistors, LED, ...),
Front panel elements (switches, potentiometers, knobs),
Connectors, relays,
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 AB528 kit is an easy build.
There is no setup needed.

Product Options
XT500 Extender: The XT500 option is a cable extension that allows you to test and setup the module outside the lunchbox while connected.

501 Case: The 501 case option is a standalone, single slot lunchbox with PSU.
The XT500 Extender is not needed with the 501.

Assembled Product: If you prefer not to DIY, choose an Assembled product. It comes fully assembled, ready to use.

https://www.soundskulptor.com/en/proddetail.php?prod=MP-AB528