The MP573 is a two stages, single ended class A preamp, based on the design that was originally used in the Neve 1290/1073 modules, that has been adapted to the '500' format of API.
Just install it in your API* compatible LunchboxTM rack and start recording.
The sound of the MP573, like its model is full, silky, detailed and musical, slightly larger than life, very complimentary to a digital recording environment.
The MP573 is great on vocals, acoustic instruments and generally all close miked sources that need to be pushed forward in the mix.
- Single ended class A design
- Carnhill/St. Ives transformers on input and output
- 0 to 70 dB of gain
- Switchable 300 & 1200 Ohms and line level input impedance
- Switchable first stage
- The output stage is biased in a rich Class A with 70mA of iddle current
- Fet DI input, relay switched, the signal passes through the input transformer
- Signal/Clip LED monitors clipping in both stages
- 24V supply built from the +/-16V with a linear regulator
- Controlled inrush current for lunchboxes with sensitive power supply
- Golden contacts on relays and switches
- High quality Grayhill gain switch
- High precision aluminium knobs
- Tantalum capacitors in the audio path (as in original)
- High grade 105°C low ESR electrolytic capacitors
- WIMA film capacitors
- High grade double sided PCB with plated holes
- Easy build, dense but straightforward
- Available assembled or as a full kit (everything included)
1 Output level: Potentiometer that sets the signal level to the output stage
2 Signal/Clip LED: Flashes green when a signal is present and turns red 3 dB before clipping
3 Gain switch: In combination with the level potentiometer the overall gain can be set between 0 and +70dB. The 10 and 20 positions entirely bypass the input stage.
4 Input impedance: Center is the standard 1200 Ohms input impedance. Left sets a 300 Ohms low impedance, useful for ribbon mics that also adds 6 dB of gain. Right sets a 10 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 megohm) for instruments. The instrument signal goes through both transformers.
What's in the kit?
- Passive components (resistors, capacitors),
- 2 Carnhill transformers
- Active components (diodes, transistors, LED, ...),
- Front panel elements (switches, potentiometers, knobs),
- Connectors, relay,
- Front panel and side panel,
- All hardware
You bring the solder (use good quality solder, 1mm diameter max) and the Lunchbox.
The MP573 kit is an easy build in spite of a rather large number of components.
The only setup is adjusting the bias current in the output stage. It requires a standard DC voltmeter.
|Iddle supply current
||No input signal
V+ : +92mA
V- : -92mA
||300Ω, 1200Ω and 10kΩ
|Maximum input level
|Maximum output level before clip
||+70dB (+76dB in 300 Ohms)
Deviation < 1dB
|DI input impedance
|DI gain range
||-22dB to +48dB
|DI max input level